BENIGN TUMORS AND CYSTS OF THE SALIVARY GLANDS: CLASSIFICATION AND ORIGIN, HISTOLOGICAL STRUCTURE, CLINICAL FEATURES, DIFFERENTIAL DIAGNOSIS, PRINCIPLES AND METHODS OF  TREATMENT. TEST YOUR KNOWLEDGE OF  THE “BENIGN TUMORS OF  THE MFA SOFT TISSUES AND BONES.” PROTECTING OF MEDICAL HISTORY.

 

Salivary glands Normal Anatomy

General

========================================================================= Parotid gland

– Largest salivary gland (15-30g), 6 x 3 cm

– Has broad superficial lobe and smaller deeper lobe, with facial nerve usually between both lobes

– Difficult to surgically remove all parotid tissue

– Stensen’s duct (main duct) empties into oral cavity opposite crown of second maxillary molar

– 20% have accessory parotid gland and duct, usually overlying the masseter

– Parotid gland has own fascia (capsule), which is continuous with superficial layer of deep cervical fascia

– Contains 3-24 lymph nodes (not all with complete structural organization), usually lateral to facial nerve in superficial lobe

 

Submandibular gland

– Called submaxillary gland because British anatomists refer to mandible as “submaxilla”

 In submandibular triangle formed by anterior and posterior bellies of digastric muscle and inferior margin of mandible

 

– Weighs 50% of parotid gland (7-15g)

– Has own capsule, which is continuous with superficial layer of deep cervical fascia

– Wharton’s duct (submandibular duct) empties into floor of mouth on both sides of tongue frenulum at sublingual caruncula

– Lingual nerve wraps around Wharton’s duct, CN XII runs inferior and parallel to Wharton’s duct

– No lymph nodes within capsule, but 3-6 adjacent lymph nodes in submandibular triangle

 

Sublingual gland

– Smallest of major salivary glands (2-4g)

– Lies deep to floor of oral mucosa between mandible and genioglossus muscle

– Has no true fascial capsule

– Has no single dominant duct, but is drained by 10 small ducts (ducts of Rivinus)

– Occasionally, several of more anterior ducts may join to form a common duct (Bartholin’s duct), which typically empties into Wharton’s duct

– Bartholin’s duct unites with the submandibular duct just prior to its opening into the oral cavity at the sublingual caruncula on both sides of tongue frenulum

 

Minor salivary glands

– Except for the gingiva and anterior hard palate, minor salivary glands (500-1000, 1-5 mm each) are located throughout the submucosa of the oral cavity

– More numerous in posterior hard palate

– Each salivary unit has its own simple duct

– Most of these minor salivary glands are mucinous with the main exception of Ebner’s glands which are serous glands located in the circumvallate papillae of the tongue 

AFIP Figure 1-7: The right and left submandibular ducts (arrows) course anteriomedially in the floor of the mouth to openings at the lingual carunculae, which are only a few millimeters apart.

 

Salivary Gland Illness

The non-cancerous salivary gland diseases represent a disparate group of disorders affecting both the major and minor salivary glands. They range from inflammatory disorders of infectious or autoimmune etiology to obstructive and idiopathic disorders. The major salivary glands are most often involved, and many of these salivary gland problems are associated with the presence of other systemic diseases. A thorough history and physical examination is typically adequate to recognize and differentiate this group of conditions and can make elaborate diagnostic evaluations unnecessary.

Many of the granulomatous, autoimmune and idiopathic salivary problems have medical solution and will not be dealt with further here. We will instead make greater mention of those problems for which the special skills of the head and neck surgeon are more often sought.

Inflammatory Disorders

Acute inflammation of the salivary glands is called “acute sialadenitis,” and is usually of viral or bacterial origin. Of the viral types, mumps is the most common (caused by a virus of the paramyxovirus group), but salivary gland involvement may be seen in a wide range of other viral illnesses including those caused by cytomegalovirus, lymphocytic choriomeningitis virus, coxsackievirus A, echovirus, and parainfluenza virus type C. Treatment of these is symptomatic and non-surgical.

Bacterial infections commonly produce “suppurative” sialadenitis, and most often involve the parotid or, less often, the submandibular glands. The bacterium most frequently implicated is Staphylococcus aureus but Streptococcus pneumoniae, Hemophilus influenzae, and Escherichia coli are also seen.This entity often occurs in the elderly postoperative patient after cardiothoracic or gastrointestinal surgery.

Therapy is initially conservative employing hydration, sialogogues, heat, massage of the affected gland, and intravenous antibiotic. If improvement is not seen within the first 24 to 48 hours, operative intervention may be indicated.

Chronic sialadenitis

Decreased salivary flow with stasis is a key factor in chronic sialadenitis.The condition is more common in the parotid gland and it is often associated with a previous episode of acute suppurative inflammation. With chronic inflammation, alterations in salivary chemistry and enzyme and immunoglobulin content take place. Symptoms include recurrent mildly painful swelling of the parotid which often accompany eating and most patients experience permanent dry mouth (“xerostomia”).

Treatment is initially similar to that for acute sialadenitis and a thorough search is made for treatable predisposing factors such as stones. If conservative measures fail, ductal dilatation, ligation of the duct, irradiation or surgical removal of the gland may be performed.

Obstructive Disorders

Mucoceles and Mucous Retention Cysts

Mucoceles and mucous retention cysts usually involve the minor salivary glands of the lower lip, cheek lining or floor of the mouth. Mucoceles lack an epithelial lining and are therefore not true cysts. They likely result from ductal obstruction or trauma and accumulation of mucus in tissues.

Mucous retention cysts do have a true epithelial lining. The “ranula” ( “frog’s belly”) is a mucous retention cyst

of the sublingual salivary gland ducts that usually presents as a soft, fluid-filled mass in the floor of mouth. Treatment of these lesions involves either “marsupialization,” (creating an opening in the roof), or complete removal. The so-called “plunging ranula “ is a mucocele that has extended outside the floor of mouth into the area under the anterior jaw via a defect in the mylohyoid muscle. They require complete excision in continuity with their salivary gland of origin.

Salivary Stones (“Sialolithiasis”)

Most salivary gland stones (“calculi”) occurs in the submandibular gland (80 to 90%)with the parotid gland being home to the remaining 10 to 20%. Serum calcium and phosphorous levels have no known correlation with the stone formation. Calculi may be found within the ductal system or the salivary gland itself. In most cases a single calculus is involved. Stone formation occurs via the deposition of calcium phosphate and an organic matrix of carbohydrates and amino acids about a nidus of debris or other material. If the stone produces ductal obstruction ,blockage of saliva flow will occur with development of inflammation and possible ascending bacterial infection. Streptococcus viridans is a common offending bacterium.

Stone formation most often occurs in middle-aged males and can produce intermittent salivary gland swelling and discomfort, especially with eating. Calculi can lead to the development of chronic sialadenitis (as noted above) and may also lead to an episode of acute suppurative sialadenitis.

Diagnosis: When complicated by acute infection, mucopurulent material may be expressed from the duct with massage of the gland. X-rays (e.g. submentovertex or occlusal films) are sometimes useful in the diagnosis and location of calculi. 90% of submandibular calculi are “radiopaque” (show up on xray), but 90% of parotid calculi are “radiolucent” and don’t appear. Sialography is very accurate in the diagnosis of salivary stones. It involves the injection of dye into the salivary duct, followed by xray of the area.

Some smaller stones may pass spontaneously with appropriate conservative management including hydration, sialogogues, heat, massage, and appropriate antibiotics. Surgical stone removal may be performed through an incision in the oral cheek lining for calculi located found distally in the duct. However, calculi located near the hilum of the gland often require complete excision of the involved gland.

Benign Salivary Tumors

Tumors of the salivary glands are uncommon, representing just 2-4% of head and neck neoplasms.Tumors of the parotid gland are the most common and are 5 times more common than tumors of the minor salivary glands. The latter, though, are almost twice as common as tumors in the submandibular gland. The most common benign tumor is the benign mixed tumor, or “pleomorphic adenoma.”

Although etiology for these tumors is unknown, environmental and genetic factors have been suggested. Radiation exposure has been linked to the development of the benign Warthin tumor and to the malignant mucoepidermoid carcinoma, while Epstein-Barr virus may be a factor in the development of lymphoepithelial tumors.

The classic presentation of a benign salivary gland tumors is a painless, slow-growing mass on the face (parotid), angle of the jaw (parotid tail, submandibular), or neck (submandibular), or a swelling at the floor of the mouth (sublingual gland). Benign tumors are almost always mobile, and (for masses of the parotid gland),do not affect the function of the facial nerve.

Pleomorphic Adenoma (“benign mixed tumor”)

Pleomorphic adenomas are the most common tumors of the salivary glands and are most commonly found in the tail of the parotid gland. If found in the minor salivary glands, the hard palate is most frequently involved. These are called “pleomorphic” because they contain both epithelial and connective tissue components. Grossly they are round, smooth masses with thin, incomplete capsules. They grow slowly, but may become larger than other salivary tumors. Because the the thin capsule may have projections into the surrounding parotid tissue, it can be challenging to obtain the clean surgical margins that are needed to minimize recurrence.

Treatment of benign mixed tumors involves the complete surgical removal of the affected gland. If the parotid gland is involved, “superficial parotidectomy” with removal of the gland’s superficial lobe and facial nerve preservation is the procedure of choice.

Warthin Tumor (” papillary cystadenoma lymphomatosum”)

Described by Warthin in 1929, this tumor is a smooth, soft, parotid or submandibular mass. It is well encapsulated when located in the parotid gland and contains multiple cysts. Malignant change has not been observed. All patients with this tumor survive, and the recurrence rate is 5%. The Warthin tumor can be bilateral (10% of cases) and is generally found in the major glands.

Intraductal Papilloma

This is a small, tan, smooth lesion that is generally found in the submucosal layer. Microscopically, the tumor contains cystically dilated ducts partially lined with a cuboidal epithelium.

Oxyphil Adenoma (“oncocytoma”)

Oncocytomas of the salivary glands are very uncommon.They occur twice as often in women than in men, with patients being older than 50 years. The superficial lobe of the parotid gland is the most commonly reported location. Oncocytomas manifest as small (<5 cm in diameter), firm, slow-growing, spherical masses.

A variety of other tumors can occasionally be seen in the salivary glands. These include:

• Hemangioma

• Lymphangioma

• Lipoma

 

Testing

Some controversy exists regarding the routine use of imaging for small lesions of the superficial lobe of the parotid gland, however, CT or MRI can be useful for suspected tumors of the deep lobe of the parotid gland and of the submandibular, sublingual, and minor salivary glands. These studies are useful for evaluating the local and regional extension of such tumors.

The usefulness of Fine Needle Aspiration Biopsy is well established with many reporting accuracy rates of 74-90%. The procedure is generally safe, is simple to perform, and has low morbidity. Although some controversy exists about whether the procedure should be used for masses in the superficial lobe of the parotid, (since it may not change the management), results that are consistent with lymphoma or sialadenitis could make a large resection unnecessary and alleviate patient anxiety.

Treatment

Management of benign salivary tumors involves complete removal with an adequate margin of tissue to forestall recurrence. This usually requires the complete surgical removal of the gland containing the tumor.

Salivary Gland Tumours

The major salivary glands are the parotid glands, submandibular glands and sublingual glands. There are also a large number (600-1,000) of minor salivary glands widely distributed throughout the oral mucosa, palate, uvula, floor of the mouth, posterior tongue, retromolar and peritonsillar area, pharynx, larynx and paranasal sinuses. Tumours affecting salivary glands may be benign or malignant and are diverse in their pathology.

• 80% of salivary gland neoplasms arise in the parotid glands, 10-15% in the submandibular glands and the remainder in the sublingual and minor salivary glands.

• About 80% of parotid neoplasms are benign but the relative proportion of malignancy increases in smaller glands. About half of submandibular gland neoplasms and most sublingual and minor salivary gland tumours are malignant.

Classification

Malignant tumours

The malignant tumours most commonly affecting the major salivary glands are mucoepidermoid carcinoma, acinic cell carcinoma and adenoid cystic carcinomas. Among the minor salivary glands, adenoid cystic carcinoma is the most common. Malignant tumours are designated high-grade or low-grade dependent on their histology.

• High-grade:

• Mucoepidermoid carcinoma (grade III): mucoepidermoid carcinoma is the most common malignancy of the parotid gland and is the second most common of the submandibular gland (after adenoid cystic carcinoma). It represents about 8% of all parotid tumours.

• Adenocarcinoma – poorly differentiated carcinoma and anaplastic carcinoma; represents 2-3% of salivary tumours.

• Squamous cell carcinoma.

• Malignant mixed tumours.

• Adenoid cystic carcinoma.

• Low-grade:

• Acinic cell tumours: represent 1% of all salivary gland neoplasms. 95% arise in the parotid gland.

• Mucoepidermoid carcinoma (grades I or II).

Benign tumours

• Pleomorphic adenoma (most common): also called benign mixed tumour, is the most common tumour of the parotid gland and causes over a third of submandibular tumours. They are slow-growing and asymptomatic.

• Warthin’s tumour: second most common benign salivary gland neoplasm, representing about 6-10% of all parotid tumours. They rarely occur in other glands and 12% are bilateral. They present most often in the 6th decade in women and the 7th decade in men.^[2]

• Rarities including oncocytomas and monomorphic adenomas.

Regional metastases from skin or mucosal malignancies may present as salivary gland masses. 1-3% of patients with cutaneous squamous cell carcinoma of the head and neck experience metastatic spread to the parotid-area lymph nodes. Lymphomas may occasionally present in a salivary gland.^[3] In children, most parotid tumours are benign and are haemangiomas.^[4]

Epidemiology

• Neoplasms of salivary glands have an incidence of about 1 to 2 per 100,000 per annum in England and Wales, with about 470 new cases diagnosed every year.

• They are fewer than 1% of all cancers and 3-6% of all tumours of the head and neck.

• Tumours are most common in the 6th decade of life.

• Malignancy typically presents after age 60, whilst benign lesions usually occur after age 40.

• Benign tumours are more common in women, but malignant tumours have an equal sex distribution.

• Certain ethnic groups, eg Inuit populations, have a higher rate of salivary gland tumours which is maintained even after migration to a low incidence area. The responsible environmental or genetic factors are unknown.

Risk factors

• Radiation to the neck increases the risk of malignancy of salivary glands with a 15- to 20-year latency.

• Smoking is an important risk factor for the development of Warthin’s tumours but its relationship to malignant parotid tumours is less clear. Warthin’s tumours are eight times more common in smokers compared with non-smokers.

• Some studies have suggested an association between high use of mobile phones and an increased risk of benign and malignant parotid tumours, although others have found no evidence of such a relationship.

Presentation

In England and Wales, about 13% patients with salivary gland cancer present with early disease, 17% with locally advanced, 7% with lymph node involvement and 28% with metastatic disease (and unknown staging in 35%).

Symptoms

• Most salivary gland neoplasms are a slowly enlarging painless mass:

• Parotid neoplasms most commonly occur in the tail of the gland as a discrete mass in an otherwise normal gland.

• Submandibular neoplasms often appear with diffuse enlargement of the gland.

• Sublingual tumours produce a palpable fullness in the floor of the mouth.

• Minor salivary gland tumours vary according on the site of origin – painless masses on the palate or floor of the mouth are the most common form but laryngeal salivary gland tumours can produce airway obstruction, dysphagia, or hoarseness. In the nasal cavity or paranasal sinus they cause nasal obstruction or sinusitis.

• Facial palsy with a salivary gland mass indicates malignancy.

• Pain can occur with both benign and malignant tumours. Pain may arise from suppuration or haemorrhage into a mass or from infiltration of adjacent tissue.

Signs

Use bimanual palpation of the lateral pharyngeal wall for deep lobe parotid tumours and the extent of submandibular and sublingual masses.

• Clinical features of a salivary gland mass suggestive of malignancy are:

• Hardness.

• Fixation.

• Tenderness.

• Infiltration of surrounding structures, eg facial nerve, local lymph nodes.

• Overlying skin ulceration.

• Cranial nerve palsy.

Differential diagnosis

Referral

National Institute for Health and Clinical Excellence guidelines suggest urgent referral of patients with suspected head and neck cancer where:

• There is an unexplained lump in the neck, of recent onset, or a previously undiagnosed lump that has changed over a period of 3-6 weeks.

• There is an unexplained persistent swelling in the parotid or submandibular gland.

• The patient has an unexplained persistent sore or painful throat.

• There has been unilateral unexplained pain in the head and neck area for more than 4 weeks, associated with otalgia but a normal otoscopy.

• There has been unexplained ulceration of the oral mucosa or mass persisting for more than 3 weeks.

• There are unexplained red and white patches of the oral mucosa that are painful or swollen or bleeding.

• There have been persistent symptoms or signs related to the oral cavity (>6 weeks) and a definitive diagnosis of a benign lesion cannot be made.

Investigations

Imaging to define location, detect malignant features, assess local extension and invasion, and detect metastases and systemic involvement:

• Ultrasound is the usual initial means to assess superficial lesions. Ultrasound is more limited at visualising the deep lobe of the parotid and some minor salivary glands depending on location.

• Ultrasound-guided fine needle aspiration (FNA) cytology is used to obtain cytological confirmation. CT-guided biopsy can also be used.

• If deep tissue extension is suspected or malignancy confirmed on cytology, an MRI or CT scan is used to evaluate tumour bulk, local invasion and perineural spread.

• All tumours in the sublingual gland should be imaged with MRI as the risk of malignancy is high.

• For lesions of the deep lobe of parotid gland and the minor salivary glands, MRI and CT scanning are the imaging methods of choice.

• Sialography can be used to delineate the salivary ductal system and has a limited role in assessing tumour extent.

Staging

Staging is most commonly based on the tumour, node and metastasis (TNM) classification system – based on tumour size, spread to cervical lymph node and distant metastases. It correlates with survival and assists treatment decisions.

Management

NICE guidance urges specialisation at centres with sufficient expertise and volume of cases, as this improves care. At all stages, patients should have access to a multidisciplinary team with expertise in the treatment of head and neck tumours.

• Most current treatment depends on local ablation.

• Radiotherapy may be used following surgery, usually for higher-grade tumours, or alone for non-resectable tumours. Its use improves overall survival in high-grade, advanced parotid cancer as an adjunct to surgery.

• Response of malignant tumours to single-agent chemotherapy is generally poor and tends to be reserved for the palliative management of advanced disease that is not amenable to local therapies such as surgery and/or radiation.

• Polychemotherapy is likely to induce a higher response rate, but has not been shown to improve survival.

• Targeted molecular therapy is hoped to bring breakthroughs.

Surgical

• Superficial parotidectomy with careful dissection of the facial nerve is required for diagnosis and treatment of a parotid mass. Where malignant, a more radical procedure sacrificing the facial nerve may be undertaken, depending on the extent of infiltration. Complete excision of tumours in other salivary glands is required.

• Benigeoplasms of the submandibular gland require complete excision of the gland.

• Up to 60% of patients with malignant minor salivary gland tumours of the larynx will develop recurrent disease locally, regionally, or at distant sites. Because of the high risk of recurrence, total laryngectomy is usually recommended.

Complications

• Damage to the facial nerve may occur as a result of parotid tumour infiltration or surgery. Risk of damage is higher with repeat operations. Perioperative facial nerve monitoring may reduce this risk.

• Recurrence of benign or malignant tumours. Pleomorphic adenomas must be completely removed at primary surgery as recurrent tumours are often multifocal and can occur 10-15 years later with much reduced cure rates (<25%).

• Malignant change – pleomorphic adenomas can undergo malignant change and are called carcinoma ex-pleomorphic adenoma. They represent about 2-4% of salivary gland malignancies. Sudden rapid growth of a previously stable mass is typical. They are aggressive and have a poor prognosis.

• Frey’s syndrome (redness and sweating on the cheek, which can appear when eating, seeing or thinking about certain kinds of food which produce strong salivation) can occur after parotid surgery. The autonomic nerves reform inappropriately (parasympathetic impulses going to sympathetic nerves) so that a stimulus to salivation will make the face sweat.

• Xerostomia and oral mucositis may occur following radiotherapy.

Follow-up of patients who have had parotidectomy for benign or malignant disease shows remarkably little adverse effect on the quality of life.

Prognosis

Because salivary gland tumours are rare and so diverse, there is a shortage of good clinical trials. It is hoped that a better understanding of their molecular biology will lead to improved understanding of prognosis and better treatment.

• The mean 5-year survival for advanced high-grade parotid cancer is 35%. Where there is facial nerve involvement, this falls to 9%. Earlier-stage disease has a better prognosis – 10-year survival for stage 1 parotid tumours (tumour <2 cm with no local or metastatic spread) is 83%.

• Malignancies of the minor glands are rare but tend to have a better outcome.

• Tumours in children and adolescents are sometimes malignant but the prognosis tends to be good.

Salivary Gland Tumors, Major, Benign

Background

Tumors of the salivary glands are uncommon and represent 2-4% of head and neck neoplasms. They may be broadly categorized into benigeoplasms, tumorlike conditions, and malignant neoplasms. The glands are divided into major and minor salivary gland categories. The major salivary glands are the parotid, the submandibular, and the sublingual glands. The minor glands are dispersed throughout the upper aerodigestive submucosa (ie, palate, lip, pharynx, nasopharynx, larynx, parapharyngeal space).

Most (70%) salivary gland tumors (SGTs) originate in the parotid gland. The remaining tumors arise in the submandibular gland (8%) and minor salivary glands (22%). Although 75% of parotid gland tumors are benign, slightly more than 50% of tumors of the submandibular gland and 80% of minor SGTs are found to be malignant. Pleomorphic adenomas (benign mixed tumors) are the most common benign SGTs, comprising 85% of all salivary gland neoplasms.

Right submandibular benign salivary gland tumor in a 42-year-old woman.

Pictures before and after treatment for a benign mandibular gland tumor. Specimen picture of the gland.

The ubiquitous deposition of the minor salivary glands complicates the diagnosis and management of SGTs. The approach for a suspected tumor of the minor salivary glands begins with a thorough history and a physical examination. Radiographic imaging (CT with or without MRI) and a histopathologic diagnosis (obtained based on fine needle aspiration biopsy [FNAB]) often provide useful information prior to definitive surgical therapy.

History of the Procedure

The anatomy of the parotid gland and the role of the main ducts were described in the mid-17th century. The earliest references to “para-auricular swellings,” as the Greeks called them, described the findings associated with calculi and inflammation.

From 1650-1750, salivary gland surgery was limited to the treatment of ranulas and oral calculi. The concept of surgical excision of a parotid tumor has been attributed to Bertrandi in 1802. The initial applications of this surgery included an extensive approach, causing serious disfiguration and disability.

By approximately 1850, the focus shifted toward dissection and the intimate relationship between the facial nerve and the parotid gland. Attempts were made to perform the surgery with nerve preservation. John C. Warren, MD, was the first to use ether inhalation anesthesia during his resection of a parotid tumor in Boston in 1846. In 1892, Codreanu (a Romaniaative) performed the first total parotidectomy with facial nerve preservation. Grafting of the facial nerve after resection was attempted in the early 1950s.

Beahrs and Adson (1958) eloquently described the relevant anatomy and surgical technique of current parotid gland surgery. They stressed surgical landmarks for avoiding injury to the main trunk and branches of the facial nerve and advocated complete removal of the superficial portion of the parotid gland for noninvasive lesions confined to that portion of the gland.

Problem

SGTs usually manifest as an enlargement or growth of the major salivary glands. Depending on the location of the gland, they can be presented with nerve compression symptoms when presented later in the course with larger size tumors.

Investigate and exclude a history of weight loss, underlying infectious processes (eg, chest pain, cough, lymphadenopathy), and clinical indications of lymphoma-type B symptoms (eg, night sweats, fever).

Epidemiology

Frequency

SGTs represent 2-3% of head and neck neoplasms. Of the SGTs, 85% are pleomorphic adenomas. SGTs are more common in women than in men, with the peak incidence in the third and fourth decades of life. Pleomorphic adenomas make up 70% of parotid gland tumors and 50% of submandibular gland tumors.

Warthin tumors (adenolymphoma) account for 5-15% of SGTs. Warthin tumors are the second most commoeoplasm of the parotid gland. They are more common in men than in women, with peak incidence in the fifth and sixth decades of life.

Heterogeneous, predominantly low-density mass in the tail of the right parotid gland with minimal thin peripheral enhancement consistent with a Warthin tumor.

Of minor SGTs, 50% are malignant. Mucoepidermoid cancer is the most common parotid malignancy. Overall, adenoid cystic carcinoma is the most common malignant tumor of all minor salivary glands and, specifically, the submandibular gland.

Etiology

Although the etiology of SGTs is unknown, the involvement of environmental or genetic factors has been suggested. Radiation exposure has been linked to the development of the benign Warthin tumor and to the malignant mucoepidermoid carcinoma. Epstein-Barr virus may be a factor in the development of lymphoepithelial tumors of the salivary glands. Genetic alterations, such as allelic loss, monosomy and polysomy, and structural rearrangement, have all been studied as factors in the development of SGTs.

Pathophysiology

The histogenesis of SGTs is based on the salivary gland unit as seen in the image below.

Histology of the salivary gland unit.

According to the multicellular theory of SGTs, pleomorphic adenomas originate from the intercalated duct cells and myoepithelial cells; oncocytic tumors originate from the striated duct cells; acinic cell tumors originate from the acinar cells; and mucoepidermoid and squamous cell tumors originate from the excretory duct cells.

Presentation

The classic presentation of a benign SGT is a painless, slow-growing mass on the face (parotid), angle of the jaw (parotid tail, submandibular), or neck (submandibular) or a swelling at the floor of the mouth (sublingual). A sudden increase in size may be indicative of infection, cystic degeneration, hemorrhage inside the mass, or malignant degeneration. Benign SGTs are almost always freely mobile, and, for masses that arise in the parotid gland, facial nerve function is typically unaffected.

Because of the multiple and varied sites of minor salivary glands, the presentation of benign tumors in these sites may be less specific. For example, bleeding and airway compromise may be the first signs of minor SGTs of the nasal septum, whereas tumors of the base of tongue may present with dysphagia and a globus sensation. The authors have each observed one patient treated for a pleomorphic adenoma of the nasal septum and the base of the tongue. Benign tumors of the parapharyngeal space may present as trismus. Differentiating a benign, space-occupying lesion from one that is truly invading the masseter and pterygoid musculature is important.

Coronal MRI demonstrating benign tumor of the parapharyngeal space.

Rule out signs of a malignant lesion, such as new onset of pain, facial nerve weakness, rapid growth, paresthesias, hoarseness, skin involvement, a fixed lesion, and cervical lymphadenopathy.

Tumors of the salivary glands are classified based on their cytological, architectural, and biological characteristics. The World Health Organization classification of 1992 groups both benign and malignant tumors into epithelial and nonepithelial categories. Benign epithelial tumors include pleomorphic adenoma, Warthin tumor, monomorphic adenoma, intraductal papilloma (IDP), oncocytoma, and sebaceous neoplasms. Benigonepithelial tumors (mesenchymal origin) include hemangioma, angioma, lymphangioma (cystic hygroma), lipoma, and neural sheath tumors.

An additional category of tumor-like lesions includes necrotizing sialometaplasia, benign lymphoepithelial lesions, cystic lymphoid hyperplasia (in persons with AIDS), and salivary gland cysts.

Benign epithelial tumors

Pleomorphic adenoma

Pleomorphic adenomas (benign mixed tumors) are the most common tumors of the salivary gland and are most often located in the tail of the parotid gland. When found in the minor salivary glands, the hard palate is the site most frequently involved, followed by the upper lip.

Note the 12-mm right parotid, smoothly marginated, multilobulated, solid lesion, without focal calcification or necrosis. This was proven to be pleomorphic adenoma.

Note the 2 X 1.5-cm uniformly enhancing, smoothly marginated mass in the superficial right parotid gland without necrosis or calcification, which is consistent with an epithelial neoplasm such as pleomorphic adenoma.

These tumors were termed pleomorphic because of the epithelial and connective tissue components that compose them in varying degrees. Their gross appearance is a round, smooth mass with a thin, delicate, incomplete capsule. Of note, pleomorphic adenomas that arise in the minor salivary glands usually lack a capsule. These tumors grow slowly, although they may become larger than other SGTs. The thin, delicate capsule may have projections into the surrounding parotid tissue. This is of particular clinical significance because obtaining clean margins and avoiding spillage are mandatory to minimize recurrence.

Microscopically, benign mixed tumors are characterized by variable, diverse, structural histologic patterns. Frequently, they have growth patterns of sheets, strands, or islands of spindle and stellate cells, with a myxoid configuration occasionally predominating. Treatment of benign neoplasms involves the complete surgical excision of the affected gland. If the parotid gland is involved, superficial parotidectomy with standard facial nerve dissection and preservation is the procedure of choice. Enucleation is contraindicated because of the tendency towards tumor spillage that can lead to tumor recurrence.

Warthin tumor (ie, papillary cystadenoma lymphomatosum, cystic papillary adenoma, adenolymphoma)

Albrecht first recognized this tumor in 1910, and Warthin later described it in 1929. In gross appearance, it is a smooth, soft, parotid mass. It is well encapsulated when located in the parotid gland and contains multiple cysts. Histologically, the Warthin tumor has a heavy lymphoid stroma and aciniform epithelial cells that line the cystic areas with papillary projections. Malignant transformation has not been observed. All patients with this tumor survive, and the recurrence rate is 5%. The Warthin tumor tends to be bilateral (10% of cases) and is usually found in the major glands, as are most other types.

Intraductal papilloma

IDP is a small, tan, fairly smooth lesion that is usually found in the submucosal layer. Microscopically, IDP consists of a cystically dilated duct partially lined with a cuboidal epithelium with complex anastomosing papillary fronds of variable size filling the cystic area. IDP of the minor salivary gland is a rare lesion that has been described only in various case reports.

Histologically, the differential diagnosis of IDP includes papillary cystadenoma, which is commonly but erroneously diagnosed as IDP. In papillary cystadenoma, intraductal hyperplasia occurs and the dilated duct contains some papillary folds and projections. However, this occurs much less frequently than in IDP.

Oxyphil adenoma (oncocytoma)

Duplay first described the oncocytic tumor in 1875. Oncocytomas of the salivary glands are very uncommon. Such neoplasms occur more often in women than in men, with a female-to-male ratio of 2:1. Patients are older than 50 years, and the superficial lobe of the parotid gland is the most commonly reported location. Oncocytomas rarely, if ever, occur in the minor salivary glands. Oncocytomas manifest as small (< 5 cm in diameter), firm, slow-growing, spherical masses. Bilateral oncocytomas of the parotid glands have been described. Histologically, they are large and spherical and have a distinct capsule. Uniform cells are arranged in solid sheets. These tumors recur if excision is incomplete.

Benigonepithelial tumors

Hemangiomas

Hemangiomas are the most common SGTs in children and usually involve the parotid gland. Less often, they may involve the submandibular gland. These vascular tumors may be distinguished from vascular malformations by their presence early in life, rapid growth phase in children aged approximately 1-6 months, and gradual involution over 1-12 years. The typical presentation is an asymptomatic, unilateral, compressible mass. Gross examination reveals a dark red, lobulated, unencapsulated mass. Microscopically, hemangiomas are composed of solid masses of cells and multiple anastomosing capillaries that replace the acinar structure of the gland. Because they lack a capsule, they tend to infiltrate neighboring structures.

Treatment should initially consist of steroids administered 2-4 mg/kg/d. Although the response may be immediate, only 40-60% of hemangiomas exhibit a response to steroids. Despite the tendency toward spontaneous involution, specific conditions may warrant surgical excision.

Lymphangioma (cystic hygroma)

Lymphangiomas are most commonly located in the head and neck region of infants and children. They are believed to be due to lymphatic sequestration of primitive embryonic lymph ducts that undergo irregular growth and canalization. They are spongy, multiloculated masses with a yellowish or bluish surface and are formed by endothelial-lined spaces. More than 50% manifest at birth, and 80% manifest by age 2 years. Usually, they manifest as painless masses that may involve parotid glands, submandibular glands, or both. Diagnosis is made based on clinical findings. Surgical excision with preservation of the vital structures is the treatment of choice. Lymphangiomas rarely cause symptoms of airway obstruction, and excision is usually for cosmetic reasons.

Lipoma

Lipoma tumors are relatively uncommon in a major salivary gland. They derive from fat cells and appear grossly as smooth, well-demarcated, bright-yellow masses. Histologically, the tumor consists of mature adipose cells with uniform nuclei.

These tumors manifest as soft, mobile, painful masses and peak in the fifth and sixth decades of life, with a male-to-female ratio of 10:1. They are slow-growing tumors with an average diameter of 3 cm. Treatment is surgical excision.

Tumorlike lesions

Necrotizing sialometaplasia

Necrotizing sialometaplasia may easily be mistaken for a malignant tumor because it presents as a single, unilateral, painless or slightly painful lesion on the hard palate. However, it is a benign, self-healing lesion of the minor salivary glands that is seen in adults older than 40 years and is 2-3 times more common in men than in women. Although the etiology is unknown, it may represent a reparative process in response to ischemic necrosis of salivary tissue. A biopsy helps to rule out a malignant process; otherwise, no treatment is indicated.

Lymphoepithelial hyperplasia (Mikulicz disease, sicca complex, chronic punctate sialadenitis)

This disorder can manifest as a diffuse enlargement of all or part of the parotid gland, or it may manifest as a discrete mass.

Histologically, the lesion is composed of a diffused, well-organized lymphoid tissue and lymphocytic interstitial infiltrate with obliteration of the acinar pattern.

Lymphoepithelial hyperplasia is more frequent in females than in males, and its peak incidence is in the fourth and fifth decades of life. Occasionally, both parotid glands are involved. The growth of this tumor is slowly progressive, and it gives rise to pain around the ear or the retromandibular area.

Metastatic tumors

Metastatic disease of the parotid gland

Of these metastatic tumors, 46% are melanoma, 37% are squamous cell carcinoma, and 17% are various other tumors. This diagnosis carries a poor prognosis.

Indications

Indications include a mass of the face, neck, and floor of the mouth and the presence of clinical signs of malignancy. Such clinical signs of malignancy include a rapid growth on a slow growing tumor, bleeding, airway compromise due to larger size tumors, and nerve dysfunction (eg, paresthesia).

As a rule, excise all SGTs. Eneroth et al and others have advocated fine-needle aspiration (FNA) application and reported accuracy rates of 74-90%.^[9] FNA is mainly useful ionneoplastic masses, metastatic tumors to the parotid gland, and nonsurgical lymphomas.

Almost all neoplasms should be removed surgically because only positive diagnostic results from FNA are significant.

Relevant Anatomy

The parotid gland is situated in the musculoskeletal recess formed by portions of the temporal bone, atlas and mandible, and their related muscles. The gland has a superficial and deep lobe, between which runs the extratemporal portion of the facial nerve. The deep lobe is in contact with the parapharyngeal space. The deep cervical fascia surrounds the parotid gland. This fascia has an anteroinferior portion that becomes the stylomandibular ligament, separating the parotid gland from the submandibular gland.

The facial nerve exits the stylomastoid foramen just posterior to the base of the styloid, gives off small branches to the postauricular and posterior belly of the digastric muscles, and then turns anterolaterally. The main trunk then becomes embedded in parotid tissue and divides into temporofacial and cervicofacial branches just superficial to the retromandibular vein and external carotid artery. Beyond this point, the nerve anatomy varies some; however, 5 general peripheral nerve branches exist: frontal, zygomatic, buccal, marginal mandibular, and cervical. Surgical landmarks for the main trunk of the facial nerve include the tragal pointer and the tympanomastoid suture line.

Facial nerve branches.

Facial nerves. Note the 2 main trunks, frontozygomatic and cervical-marginal-mandibular.

The submandibular gland encompasses most of the submandibular or digastric triangle. Similar to the parotid gland, the submandibular gland can be divided into a superficial and deep lobe based on the relationship to the mylohyoid muscle. The marginal mandibular branch of the facial nerve courses between the deep surface of the platysma and the superficial aspect of the fascia that lies over the submandibular gland. The facial artery and vein are located just deep to this nerve, and ligation and superior traction of these vascular structures can prevent nerve injury. Along the posterior border of the mylohyoid are located the lingual nerve and submandibular duct (Wharton duct). The hypoglossal nerve courses deep to the tendon of the digastric and then lies medial to the deep cervical fascia.

The sublingual gland occupies the same anatomical space as the submandibular gland, located between the mylohyoid and hyoglossus muscles. The gland can often be palpated in the floor of mouth, as it is rather superficial, covered by only a thin layer of oral mucosa.

The minor salivary glands are widely dispersed throughout the upper respiratory tract, including the palate, lip, pharynx, nasopharynx, larynx, and parapharyngeal space. The greatest densities of glands are located in the hard (250 glands) and soft (150 glands) palates.

Contraindications

Experienced clinicians agree that surgical excision is indicated for all patients in whom a parotid or salivary gland enlargement develops, unless associated medical problems preclude general anesthesia.

Surgical excision aids in establishing the diagnosis and in determining the treatment plan.

Laboratory Studies

Perform a WBC count to investigate for any evidence of leukocytosis and shift that might indicate a possible infectious process or lymphoproliferative disease.

Imaging Studies

Imaging studies are most helpful in the diagnostic evaluation. MRI is the most sensitive test for establishing the borders of soft tissue tumor extension. CT scan and MRI findings, in most circumstances, cannot be used to differentiate benign from malignant disease reliably.

Dense, small, solid lesions in the parotid glands (more on the left side than on the right) in a patient with lymphoma. This is representative of lymphomatous involvement of the glands.

Ill-defined masses in the parotid glands bilaterally, proven to be large B-cell lymphoma in this patient with known Sjögren disease.

Large B-cell lymphoma in a patient with known Sjögren disease.

Large B-cell lymphoma in a patient with known Sjögren disease.

Bilateral, solid, inhomogeneous parotid gland masses that are larger on the left side than on the right, with minimal necrosis. These were caused by lymphoma.

Diagnostic Procedures

FNA may aid in the diagnosis of SGTs. The availability of an experienced cytologist is a prerequisite in this case. FNA can be helpful in identifying nonneoplastic masses that respond to medication and in identifying lymphomas and metastatic masses. FNA findings provide evidence for a preoperative diagnosis that is 70-80% accurate. The final pathologic diagnosis is always established based on findings from surgical excision.

Medical Therapy

Inflammatory infectious masses (eg, reactive, fungal) and lymphoma should be medically treated.

Salivary gland excision is also sometimes indicated when symptomatic, recurrent chronic gland infection (eg, parotitis) proves refractory to conservative treatments.

Surgical Therapy

Management of benign SGTs includes complete removal with an adequate margin of tissue to avoid recurrences. This usually involves a complete removal of the gland in which the tumor developed. Excision is performed under general anesthesia and without paralysis. The endotracheal tube is usually positioned in the corner of the mouth opposite to the surgical field.

Parotidectomy

The key to this procedure is to localize the facial nerve at the main trunk proximal to the gland safely. Include the possibility of total parotidectomy in the preoperative plan. Also discuss the potential need to sacrifice the facial nerve, with immediate grafting, cervical lymphadenectomy, and mandibulectomy.

Superficial parotidectomy remains the initial procedure of choice for benign parotid gland tumors. The incision usually starts just anterior to the ear helix, extends inferiorly below the ear lobe, and then moves anteriorly to parallel the angle of the jaw within a 2 cm distance. Dissection is usually performed sharply down to the superficial parotid fascia. Then, the skin flap is sutured and retracted from the surgical field. Dissection is continued to expose the remainder of the gland anteriorly and the anterior border of the sternocleidomastoid muscle. At this location, the greater auricular nerve is identified and preserved because it carries sensation to the ear lobule and provides the best option for nerve grafting, if needed. Note that, occasionally, deeper-lobe parotid tumors may displace the facial nerve to a more superficial location, where it can be easily injured.

In a parotid gland that is being operated on for the first time, a facial nerve stimulator is generally not necessary to identify the facial nerve. Rather, the surgeon should locate the main trunk of the facial nerve based upon recognized anatomical landmarks. At the end of the operation, the nerve stimulator may be valuable in confirming integrity of the individual nerve branches should a transient dysfunction become an issue in the postoperative period. Proper use of the stimulator involves testing it on an adjacent muscle, such as the sternocleidomastoid muscle, at a setting of 0.5 mA.

Submandibular gland surgery

Submandibular gland surgery is performed with the patient under general anesthesia with endotracheal intubation. Head rotation is to the opposite side of the tumor.

An incision is made at the mastoid process and curved along the inferior aspect of the mandible, approaching the midline. The length of the incision is approximately 4-6 cm. Take the incision down through the platysma muscle, leaving the muscle attached to the skin as a musculocutaneous flap. At this point, the marginal branch of the facial nerve is identified and preserved unless it is directly involved with the tumor. The nerve is located just below the muscle and superficial to the facial vessels. The safest technique is to divide the inferior aspect of the posterior facial vein and to raise the flap to the depth of the vessels and nerve.

Start the dissection of the gland at the level of the hyoid bone and the lower aspect of the gland. Identifying the digastric muscle is important because the hypoglossal nerve with the vessels runs in between the gland and the digastric muscle. Dissection continues on the posterior aspect of the gland, superiorly to where the facial artery is located. At this level, the blood supply to the gland is ligated. The lingual nerve is visualized by anterior retraction of the mylohyoid muscle, and the pedicle of the gland is then carefully ligated, with attention to the main trunk of the lingual nerve. Next, the Warthin duct is identified and ligated to conclude the resection.

To complete the procedure, ensure hemostasis, place a suction drain (with or without an outside pressure dressing), and perform a cosmetic layered closure.

Preoperative Details

A history of rapid growth and physical signs and symptoms (eg, facial nerve involvement) should be elicited, discussed with the patient, and documented in the preoperative evaluation chart for future reference.

Intraoperative Details

Intraoperatively, the involvement of the main trunk of the facial nerve or one or more of the main branches of the facial nerve may be encountered with the tumor. This finding may alter the plan, based on the pathology of the tumor. This is precisely the reason why it is imperative to preoperatively discuss with the patient the variable case presentations and to agree on the treatment plan. A clearly written consent, with clear preoperative documentation, is essential.

Postoperative Details

Evaluate postoperative facial, hypoglossal, and lingual nerve function. Occasionally, transient facial nerve paresis occurs; however, it usually resolves within 3-12 weeks after surgery.

Follow-up

Remove any nondissolvable sutures and drains. Detect recurrence, which could present years after surgery.

Complications

Recurrence is usually caused by inadequate excision (spillage) or inoculation. The recurrence rate, as reported after a mean follow-up period of 11.8 years, is as high as 25%.

Use proper hemostasis techniques with suction drains and compression dressing to minimize the risk of bleeding and seroma.

Iatrogenic injury is usually recognized during surgery, and, in this scenario, it should be immediately repaired.

If the facial nerve is sacrificed because of direct tumor involvement, immediate grafting (using the greater auricular nerve or sural nerve) is required.

Transient facial nerve paralysis (paresis) takes a few weeks to resolve spontaneously but can last as long as 6 months. Direct trauma to the nerve, devascularization, or postoperative nerve inflammation is believed to cause paresis.

Frey syndrome is a known complication after parotidectomy, and manifestations range from erythema related to eating to copious gustatory sweating. The cause is believed to be an aberrant connection of the parasympathetic fibers to the sweat gland of the overlying flap of skin. To minimize the chance of the patient developing postoperative Frey syndrome, raise a thick parotid flap just above the parotid fascia.

Salivary fistulae with wound healing are very uncommon.

When a submandibular gland is removed, follow surgical recommendations to avoid unintentional injury to the lingual, hypoglossal, or mandibular branch of the facial nerve.

Outcome and Prognosis

With the appropriate treatment of benign SGTs (ie, complete excision, superficial parotidectomy), the outcome is excellent and the recurrence rate is very low.

Mucocele (syn. mucous extravasation cyst; mucous retention cyst; ranula)

Introduction

A mucocele is a benign, mucous-containing cystic lesion of the minor salivary glands presenting as a distinct, fluctuant, painless swelling of the mucosa, especially the lower lip. This chapter is set out as follows:  Aetiology Clinical findings Images Management

Aetiology

• Mucoceles develop as a result of changes to the minor salivary glands, leading to mucous accumulation and local swelling

• There are two types of mucocele

• Extravasation mucocele – results from a broken salivary gland duct, with the subsequent spillage of mucous into the soft tissue around the gland

• Retention mucocele – results from the decrease or absence of glandular secretion produced by the blockage of salivary gland ducts, with a subsequent build up of mucous 

• Most mucoceles develop as a result of mechanical injury, mainly from the lower lip becoming caught between the maxillary anterior teeth and the mandibular anterior teeth during mastication or with the habit of biting one’s lip. They can also arise secondary to chronic inflammation, and occasionally are congenital

Clinical findings

• Distribution

• ​Although mucoceles can occur anywhere in the oral cavity where minor salivary glands are present, approximately 75-80% of cases occur on the lower lip, followed by the floor of the mouth (syn. ranula), ventral tongue, and buccal mucosa

• Morphology

• About 75% of lesions are smaller than 1 cm in diameter

• Superficial lesions take on a bluish to translucent hue, whereas deep lesions have normal mucosal coloration. Bleeding into the swelling may impart a bright red and vascular appearance

• Clinical features include a non-tender, mobile, dome-shaped enlargement with intact overlying epithelium

• Palpation reveals a fluctuant mass that does not blanch on compression

Images

Please click on images to enlarge, or choose to download. Images must only be used for teaching purposes and are not for commercial use. Notice and credit must be given to the PCDS and any other named contributor.

Figure: 1

Mucocele

Figure: 2

Mucocele

Figure: 3

Superficial mucocele on the hard palate

Figure: 4

Mucocele

Figure: 5

Mucocele on the floor of the mouth, also known as a ranula

Management

·         Step 1: conservative management

• In general, no treatment is needed

• Mucoceles may spontaneously resolve, especially in infants and young children. In a recent retrospective study, approximately 44% of mucoceles in children spontaneously resolved after an average of three months 

•  

·         Step 2: surgery

• For larger, more troublesome lesions, surgical excision of the mucocele along with the adjacent associated minor salivary glands is recommended

• The risk for recurrence is minimal when appropriate surgical excision has been performed

 

Salivary Gland Surgery

Parotidectomy

Parotidectomy is the removal of the parotid gland, the largest salivary gland. The paratoid is usually removed because of a tumor, a chronic infection, or a blocked saliva gland. Most parotid gland tumors are not cancerous.

The nerve that closes the eyes, wrinkles the nose, and moves the lips grows through the middle of the parotid gland. Small branches of the nerve might need to be trimmed if the gland is large and the surgeon cannot remove it. Decreased motion of facial muscles might occur while the nerve recovers from surgery. If facial movement does not completely return, rehabilitation can help restore facial movements.

 

Surgeons think of the gland as two separate lobes: a superficial lobe and a deep lobe.

The facial nerve separates the two lobes. The parotid gland can usually be removed without permanent damage to the facial nerve. A facial nerve monitoring machine (facial nerve stimulator) allows the surgeons to monitor the nerve during the operation.

 

Benign (non-cancerous) tumors usually need only the superficial lobe removed. But if a benign tumor is located deep in the gland, the deep lobe might need to be partially or completely removed.

 

In most cases, the entire gland is removed if the tumor is cancerous. If the tumor is small and low-grade (does not spread and does not grow quickly), the surgeon might be able to remove only the superficial lobe.

 

General anesthesia is required for a parotidectomy.

 

During the operation, the surgeon will determine the amount of tissue that should be removed. After the gland or section is taken, it is sent to a pathologist. The pathologist slices a thin section, freezes it, colors it with special dyes, and examines it under a microscope. This procedure is called a frozen section. The frozen section is used to determine if the tumor is cancerous or benign, and the specific type of tumor. The most common type of cancer tumor in the head and neck is called squamous cell carcinoma.

 

After surgery

After surgery you might feel:

• numbness of the earlobe and incision site from the scar

• weak face muscles

Nerves that link to the saliva producing areas in the parotid gland sometimes link with the nerves that control sweating in the skin. This might cause sweating of the skin at meal time (Frey’s syndrome).

 

A rare condition, called a salivary fistula or sialocele, can develop and cause saliva to leak through the skin.

Submandibular sialadenectomy (removal of the submandibular gland)

The submandibular gland is also called the submaxillary gland.

 

A submandibular sialadenectomy is used for chronic infections, stones, and tumors. Submandibular gland tumors are often malignant and the entire gland needs to be removed.

 

The mandibular branches of the facial nerve lies close the gland. The nerve is positioned away from the gland during surgery. A two inch incision is made below the lower jaw.

 

Many other glands in the mouth make saliva, so the mouth will still have enough saliva after the submandibular gland is removed.

 

Sublingual gland surgery

The incision for sublingual gland surgery is through the mouth. No incision is made in the face or neck.

Salivary Gland Tumor Removal

A parotidectomy is a surgery to remove a portion or entirety of the parotid gland. 

Hundreds of surgeries, called parotidectomies, are performed each year to remove benign (non-cancerous) or cancerous parotid tumors.  These tumors can develop in the various cells of the salivary glands when the body’s normal regulating mechanisms are not functioning correctly.

WHAT ARE SALIVARY GLANDS AND SALIVARY GLAND TUMORS?

The salivary glands secrete saliva into the mouth to assist in digesting foods.  Humans have 3 pairs of major salivary glands:  1) parotid glands, 2) submandibular glands, and 3) sublingual glands. The parotid glands are the largest salivary glands and are located in front of the ear in the cheek area and slightly over the jaw line. The smaller submandibular glands are located under the jaw and the sublingual glands, the smallest major salivary glands, are located under the tongue.  Hundreds of minor salivary glands, each about the size of a grain of sand, exist and line the mucous membranes inside the mouth.

Salivary gland tumors can be either benign (non-cancerous) or malignant (cancerous).  Most parotid tumors are benign but there is still a 20% chance that a parotid mass may be malignant.  The most common type of parotid tumor is a Pleomorphic Adenoma, also called a benign mixed tumor.

SYMPTOMS OF SALIVARY GLAND TUMORS

·         A “lump” in the cheek or neck

·         Benign masses are usually painless

·         Weakness of facial muscles on the side of tumor location may indicate a malignant process

TREATMENT FOR SALIVARY GLAND TUMORS

Surgical excision is the treatment of choice for nearly all salivary gland tumors – benign or malignant, unless the physical condition of the patient prohibits surgery. This may be the case in some situations involving benign (non-cancerous) tumors.  Without surgical removal, the tumors continue to grow and cause cosmetic and functional problems.  In certain cases, like the pleomorphic adenoma, there is a risk that the benign tumor will degenerate over time into a malignancy (cancer).  A parotidectomy involves removing salivary tissue containing the tumor from the surrounding tissue bed while sparing the facial nerve that controls facial movement.  This nerve passes through the parotid gland and makes this surgery more intricate and demanding.  Dr. Gunnlaugsson has extensive experience in performing parotidectomy surgery.  Dr. Gunnlaugsson is also certified by the American Board of Facial Plastic and Reconstructive Surgery and places an emphasis on cosmetic incision placement and appearance following the procedure.

Surgery for salivary gland cancer

Surgery is often the main form of treatment for salivary gland cancers. Your cancer will likely be treated with surgery if the doctor believes that he (or she) can remove it completely (the cancer is resectable). Whether or not a cancer is resectable depends largely on how far it has grown into nearby structures, but it also depends upon the skill and experience of the surgeon. Being treated by a surgeon who treats many patients with salivary gland cancer gives you the best chance of having your cancer completely removed with surgery. This, in turn, gives you the best chance of being cured.

In most cases, the cancer and some or all of the surrounding salivary gland will be removed. Nearby areas of soft tissue may be removed as well. If the cancer is high grade (more likely to grow and spread quickly) or if it has already spread to lymph nodes, the surgeon will usually remove lymph nodes from the same side of the neck in an operation called a neck dissection.

Before surgery, ask your surgeon exactly what will be done during the operation, whether there are other options, and what side effects you can expect.

The type of surgery will depend on which salivary gland is affected.

Parotid gland surgery

Most salivary gland tumors occur in the parotid gland. Most parotid gland tumors are benign. Surgery here is complicated by the fact that the facial nerve, which controls movement on the same side of the face, passes through the gland. For these operations, a cut (incision) is made in the skin in front of the ear and may extend down to the neck.

Most parotid gland cancers start in the outside part of the gland, called the superficial lobe. These can be treated by removing only this lobe, which is called a superficial parotidectomy. This usually spares (does not injure) the facial nerve and so does not interfere with facial movement.

If your cancer has spread into deeper tissues, the surgeon will remove the entire gland. This operation is called a total parotidectomy. If the cancer has grown into the facial nerve, it will have to be removed as well. If your surgeon has mentioned this surgery as a possibility, ask about operations to repair the nerve and ways to treat side effects caused by removing the nerve. If the cancer has grown into other tissues near your parotid gland, these tissues might also need to be removed.

Submandibular or sublingual gland surgery

If your cancer is in the submandibular or sublingual glands, the surgeon will remove the entire gland and perhaps some of the surrounding tissue or bone. Several important nerves pass through or near these glands. These nerves control movement of the tongue and the lower half of the face, as well as sensation and taste. Depending on the size and location of the cancer, the surgeon may need to remove some of these nerves.

Minor salivary gland surgery

Minor salivary gland cancers can occur in your lips, tongue, hard and soft palate (roof of the mouth), oral cavity, throat, voice box (larynx), nose, and sinuses. The surgeon usually removes some surrounding tissue along with the cancer. The exact details of surgery depend on the size and location of the cancer.

Possible risks and side effects of salivary gland surgery

With any salivary gland cancer surgery, the surgeon may need to cut through your skin or your mouth. You may have problems with anesthesia or with wound healing, infections, or excessive bleeding during or after surgery. Most people will have some pain for a time after the operation, although this can usually be controlled with medicines.

If your facial nerve is damaged during surgery, you may lose control of your facial muscles on the side where the surgery was done. That side of your face may droop. Damage to other nerves may cause problems with speech or swallowing. If the injury to the facial nerve is related to retraction (pulling) of the nerve during surgery and/or swelling from the operation, the weakness may just be temporary.

Sometimes, nerves cut during surgery grow back abnormally and become connected to the sweat glands of the face. This condition, called Frey syndrome or gustatory sweating, results in flushing or sweating over areas of your face when you chew. Frey syndrome can be treated with medicines or with additional surgery.

Depending on the extent of the operatioeeded, your appearance may be changed as a result of surgery. This can range from a simple scar on the side of the face or neck to more extensive changes if nerves, parts of bones, or other structures need to be removed. It’s important to talk with your doctor before the surgery about what these changes might be to help prepare you for them. He or she can also give you an idea about what options might be available afterward, such as reconstructive surgery.

Lymph node removal

Surgery to remove lymph nodes is called a lymph node dissection or lymphadenectomy. Salivary gland cancers sometimes spread to lymph nodes in the neck (cervical lymph nodes), and these may need to be removed as a part of treating the cancer. This is called a neck dissection. If lymph nodes in the neck are enlarged or if a PET scan suggests they may contain cancer, then a neck dissection may be done to be sure all of the cancer is removed. The lymph nodes that are removed are looked at under the microscope to see if they really contain cancer cells. This information is important for staging and deciding on the need for further treatment. A lymph node dissection may also be done if the cancer is high grade (looks very abnormal under the microscope) and has a high risk of spread.

There are many types of neck dissections, but their major purpose is to remove lymph nodes that might contain cancer. In doing this, the surgeon may need to remove connective, muscle, and nerve tissues, and blood vessels from one side of your neck.

Possible side effects

The general risks with a neck dissection are similar to those with any other type of surgery, including problems with anesthesia, bleeding, infections, and poor wound healing. Because this surgery can affect nerves that run through the neck, it can sometimes lead to ear numbness, weakness in raising your arm above your head, and weakness of the lower lip. These may get better with time. You can be helped by physical therapists who can teach you exercises to improve your neck and shoulder movement.