Ameloblastoma, osteooklastoma, osteoma, osteodysplaziya, fibrous osteodysplaziya, eozynofilnaya granuloma, hemangioma, fibroma, chondroma. X-ray diagnosis, differential diagnosis and treatment. Bone grafts in bone tumors.
Benign Nonodontogenic Lesions of the Jaws
Benign nonodontogenic lesions of the jaws represent a mixed group of tumors, which in many cases are difficult to classify. Additionally, there are some lesions within this group that actually only seem to occur in the jaws, and, therefore, although they do not contain any histologic or immunohistochemical evidence of odontogenic structures, the mere fact that they only occur in the jaws may mean that they are in fact odontogenic. The subjects discussed in this chapter are fibro-osseous disease, osteoblastoma and osteoid osteoma, aggressive mesenchymal tumors of childhood, benign tumors of bone-forming cells, synovial chondromatosis and osteochondroma, lesions containing giant cells, vascular malformations, Langerhans cell histiocytosis, nonodontogenic cysts of the jaws, neurogenic tumors, Paget’s disease, massive osteolysis (Gorham’s disease), and tori.
Benign Fibro-osseous Disease Differences remain in the classification and diagnosis of fibro-osseous disease.1 There is a general consensus that the common entity for all of the lesions is the replacement of normal bone with a tissue composed of collagen fibers and fibroblasts that contain varying amounts of mineralized substance, which can be either bone or cementum-like material. It is difficult to differentiate conclusively between bone and cementum with light microsurgery. For the purposes of this chapter, the term fibro-osseous disease is taken to include the following groups of lesions: fibrous dysplasia, cemento-osseous dysplasia, and fibro-osseous neoplasms.
Fibrous Dysplasia
Fibrous dysplasia is considered to be a developmental hamartomatous fibroosseous disease of unknown etiology. It may represent developmental arrest in a benign fibro-osseous proliferation that lacks the ability to fully differentiate.2 Somatic mutations in the GS α-gene have been proposed to cause monostotic and polyostotic conditions and Albright’s syndrome.3,4 Fibrous dysplasia is normally subdivided into four different forms: 1. Monostotic fibrous dysplasia affecting only one bone 2. Polyostotic fibrous dysplasia affecting multiple bones 3. Albright’s syndrome in which multiple lesions are associated with hyperpigmentation and endocrine disturbances, predominantly precocious puberty and/or hyperthyroidism5 4. Craniofacial fibrous dysplasia confined to bones of the craniofacial complex The jaws are commonly associated with all forms of fibrous dysplasia. In the jaws the onset is usually during the first and second decades, and it produces painless swelling of the involved bones (Figure 31-1). Classically, the radiographic appearance shows a ground-glass opacity without clearly defined borders (Figure 31-2). In its craniofacial form the maxilla, zygoma, sphenoid, frontal bones, nasal bones, and base of the skull can be involved. Expansion can cause compression of nerves and blood vessels.
The optic canal can be narrowed by fibrous dysplasia, although it seems unlikely that
any associated vision loss can be relieved by orbital decompression.6 The maxilla appears to be affected more often than the mandible, and females are affected more commonly than males. Typically lesions undergo periods of activity and periods of quiescence. When they are active, they are often symptomatic in that the patient may perceive a throbbing or discomfort, the swelling increases, and the lesions appear hot on a bone scan (Figure 31-3) and can, in fact, mimic osteomyelitis.7–11 In a quiescent phase they may be totally asymptomatic. Teeth can be displaced by the lesion (Figure 31-4). Familial cases of fibrous dysplasia have been noted.12 The lesions of fibrous dysplasia may be under hormonal control, particularly in Albright’s syndrome, and cases of increased activity and reactivation during pregnancy have beeoted.13,14 Although not normally recognized as a premalignant lesion, sarcomatous change has beeoted in fibrous dysplasia.15,16 Early cases appear to have been associated with the use of radiation therapy for treatment,17,18 but cases of spontaneous sarcomatous degeneration have beeoted.19 Additionally, some cases have been difficult to diagnose and may have represented a low-grade osteosarcoma from the outset.20 Classically, fibrous dysplasia appears to be a lesion that “burns itself out” when the patient is in the late teens or early twenties, although cases of active fibrous dysplasia have beeoted much later than this. Treatment is generally symptomatic; if the lesions are asymptomatic, a biopsy diagnosis alone may be adequate without carrying out any definitive treatment. Surgical treatment should be limited during an active phase because the lesions are vascular and can bleed quite profusely. Treatment is best reserved for quiescent periods, at which time cosmetic recontouring is the normal treatment of choice. Regrowth, however, can be expected following this treatment in 25 to 50% of cases, particularly if undertaken at a young age. Some investigators have suggested more aggressive surgical procedures including mandibular and maxillary resections.21
Cemento-osseous Dysplasia
The cemento-osseous dysplasias represent a pathologic process of the tooth-bearing areas and probably represent the commonest manifestation of fibro-osseous disease; however, since they are frequently asymptomatic and require no treatment, they are less of a diagnostic and clinical dilemma than are the other forms of fibro-osseous disease. In this condition there is a disordered production of bone and cementumlike tissue in the jaws. The three forms include periapical, focal, florid osseous dysplasias, and familial gigantiform cementoma, which are probably variants of the same pathologic process but which can be differentiated by clinical and radiographic features. The etiology of these lesions remains in doubt, but local trauma may play some part, even such benign trauma as abnormal occlusal forces. There is a predominance of cases occurring in females and also in African Americans.22 It is suspected that the periodontal ligament may be the origin of the fibrous tissue found in the cemento-osseous dysplasias. Histologically the three types of cemento-osseous dysplasia are indistinguishable, showing new woven bone trabeculae and/or spherules of cementum-like material, which often blend into the cortical bone. A fibrous tissue stroma is present. There is very little inflammatory component. Traumatic bone cysts have been reported in conjunction with this lesion.23
Periapical Cemento-osseous Dysplasia
Periapical cemento-osseous dysplasia presents as circumscribed lesions in periapical areas associated with vital teeth, with the anterior mandible being most usually
involved. African American females are predominantly affected. Radiographically the lesions can be radiolucent, of mixed density, or radiopaque, depending on their stage of development (Figure 31-5). Studies indicate that they may occur in around 6% of African American females.24
Focal Cemento-osseous Dysplasia
Lesions of focal cemento-osseous dysplasia have a predilection for middle-aged African American females and present as nonexpansile radiolucencies with associated opacities, often in edentulous areas of the mandible. They frequently occur in sites of previous dental extractions and may represent some type of abnormal healing following dental extraction. Since they are usually asymptomatic, cases are ofteoted on routine panoramic radiographs. They are normally well circumscribed and rarely exceed 2 cm. Differentiation from ossifying fibroma may be difficult.25
Florid Cemento-osseous Dysplasia
Florid cemento-osseous dysplasia has a predilection for middle-aged African American females and presents as a painless nonexpansile lesion often involving two or more jaw quadrants. Radiographically it appears as multiple confluent lobular radiopaque masses in tooth-bearing areas (Figure 31-6). Lesions may be associated with superimposed infection and osteomyelitis, and have also been associated with idiopathic bone cysts.26 Histologically they have an unencapsulated proliferation of cellular fibrous tissue with trabeculae or woven bone and calcification.More mature lesions may become acellular and avascular with coalescent sclerotic bone masses. Although common in African Americans, florid cemento-osseous dysplasia has beeoted in all racial groups. Many patients are partially or totally edentulous when the condition is first discovered. Cortical expansion is usually absent or of limited degree. It has been suggested that chronic diffuse sclerosing osteomyelitis may represent a variant of this condition, but it probably represents a different condition, inflammatory iature. The differences between the two conditions have beeoted and described.8,27,28 However, the role of bacteria in chronic diffuse sclerosing osteomyelitis has proven elusive, and, in general, even authorities who strongly support an infectious origin have had difficulty isolating organisms.29,30
Familial Gigantiform Cementoma
Familial gigantiform cementoma represents an autosomal dominant variant of osseous dysplasia usually involving multiple quadrants with variably expansile lesions, often in the anterior mandible.31 This particular form of osseous dysplasia has no racial predilection. The lesions often evolve during childhood and can grow rapidly. Treatment is usually surgical and symptomatic and is limited to cosmetic recontouring.
Fibro-osseous Neoplasms Ossifying Fibroma
Ossifying fibroma (cemento-ossifying fibroma) usually presents as a well-demarcated mixed radiolucency/ radiopacity with smooth and often sclerotic borders (Figure 31-7). The lesions are usually solitary and most commonly occur in the mandible. Histologically they contain a relatively avascular cellular fibrous stroma with reticular bone trabeculae and cementum-like spherules. Most authorities now feel comfortable clearly differentiating this lesion from fibrous dysplasia. Chromosomal abnormalities have been identified in an ossifying fibroma and a cementifying fibroma.32,33 The ossifying fibroma is felt to be a true neoplasm and occurs at a later age than does fibrous dysplasia, being most common later in the third and early in the fourth decades. Ossifying fibroma appears to be confined to the jaws and craniofacial complex, although similar lesions have been reported in the long bones.34–36 There is, again, a female predominance but no racial predominance, and growth rates are variable. Since it is felt to be a neoplasm, the treatment is surgical; in fact, the lesions often shell out easily at surgery, although there is recurrence, the rate of which has variously been reported from 1 to 63%.37–39 For these reasons, some authorities recommend aggressive treatment for more aggressive lesions, including aggressive curettage, localized surgical resection, and segmental mandibular resection.40,41 When present in the craniofacial complex, treatment may have to be more aggressive to protect the vital structures.42
Juvenile Aggressive Ossifying Fibroma
Juvenile aggressive ossifying fibroma was first described in 1952 as a variant of ossifying fibroma.43 The lesions classically occur in younger children and adolescents and present with an aggressive behavior, but they have beeoted in older patients and are not always particularly aggressive. The World Health Organization defines juvenile aggressive ossifying fibroma as “an actively growing lesion mainly affecting individuals below the age of 15 years, which is composed of a cell-rich fibrous tissue containing bands of cellular osteoid without osteoblastic rimming together with trabeculae of more typical woven bone. Small foci of giant cells may be present, and in some parts there may be abundant osteoclasts related to the woven bone. Usually no fibrous capsule can be demonstrated, but the lesion is well demarcated from the surrounding bone.”44 Two variants have been described: trabecular and psammomatous. The trabecular variant usually occurs in childhood, with a slight maxillary predominance, and may contain clustered multinuclear giant cells. The psammomatous variant can occur in adults as well as adolescents and often affects the orbit and paranasal tissues; frequently it contains a whorled pattern of closely packed spheric ossicles and a myxoid component with aneurysmal bone cyst–like areas. Although felt to be more aggressive than the commoner ossifying fibroma that is found at a later age, this condition is not considered to necessitate truly aggressive surgery; conservative excision is still the recommended treatment, although lesions involving the craniofacial structures may require more extensive surgery. Recurrence rates of between 20 and 50% have been reported, and recurrences may be commoner in younger patients.1
Osteoblastoma and Osteoid Osteoma
Osteoblastoma and osteoid osteoma are generally felt to be variants of the same lesion and are related to fibro-osseous disease. Cementoblastoma and gigantiform cementoma are the equivalent cemental lesions and are associated with teeth. The alternative name for the osteoblastoma is giant osteoid osteoma, and it is generally felt to represent a larger version of the osteoid osteoma. Both are benign processes and are felt to represent true neoplasms. The osteoblastoma occurs primarily in the vertebrae and long bones, but it has been described in the jaws.45–47 Clinically it often grows rapidly and the predominant clinical feature is pain, which is generally localized to the lesion itself. Although felt to be a true neoplasm, there have been reports of regression after biopsy or incomplete removal, which could point to it being a reactive process of some kind.48 Most cases of osteoblastoma occur in the second decade of life; they rarely occur after age 30 years. Males appear to be affected more commonly than females. In the head and neck, the mandible is the most common site. Radiographic features are variable, usually consisting of a combination of radiolucency and radiopacity (Figure 31-8). The designation osteoblastoma is normally reserved for lesions > 2 cm in diameter. They are well circumscribed radiographically with a thin radiolucency surrounding the variably calcified contents. A sunray pattern of new bone formation similar to that described in malignant bone tumors may be evident. The histologic appearance shows irregular trabeculae of osteoid and immature bone within a predominantly vascular stromal network. There are various degrees of calcification present. Stromal cells are generally small and slender. Differentiation must be made from the ossifying fibroma, fibrous dysplasia, and osteosarcoma. Treatment of the osteoblastoma is generally confined to conservative surgical excision either with curettage or local excision. Recurrences are rare but have been reported and may necessitate more aggressive treatment such as en bloc resection.49 Rare examples of malignant transformation have been reported,50,51 but some of these may be related to an incorrect initial diagnosis.45 The osteoid osteoma represents a smaller version of the osteoblastoma and is felt to be a true neoplasm. It is normally < 2 cm in diameter clinically and radiographically. It again occurs in the second and third decades of life with a male predominance. Pain is again the major clinical feature. Classically, the pain is worse at night and is relieved by acetylsalicylic acid. If the lesion is located near the cortex, it may produce a localized tender swelling. Radiographically the lesion again shows a welldefined mixed radiolucency/radiopacity with a small radiolucent rim around the lesion, which is walled by sclerotic bone. Histologically it resembles the osteoblastoma with a rich vascular stroma with trabeculae of osteoid and immature bone. The bone is rimmed by layers of active osteoblasts.Histologically it is impossible to differentiate it from the osteoblastoma. Treatment is again conservative surgical excision. Spontaneous regression has also been reported clinically.
Chondroma A chondroma is a benign tumor of mature cartilage. The occurrence of these lesions in the jaws is extremely rare52; in fact, whether they ever occur in the jaws or whether they are usually described as chondromyxomas or chondromyxoid fibromas has been questioned. 53–57 In many cases the true diagnosis in those reported cases is actually low-grade chondrosarcoma.58 Most reports concern the mandibular condyle, suggesting that these lesions may arise from cartilaginous remnants.59,60 The chondroma presents as a painless slowly progressive swelling, which may result in mucosal ulceration. The gender distribution is equal, and most tumors occur under the age of 50 years. Radiographically they present as irregular radiolucent lesions, although foci of calcification may occasionally be present. Resorption of tooth roots has been reported. Histologically the lesions contain welldefined lobules of mature hyaline cartilage. Treatment is localized, and conservative surgical excision is normally recommended. Because of the doubtful nature of these lesions and the always-present possibility of a lesion representing a low-grade chondrosarcoma, some authorities have suggested wide excision for all of these lesions as a kind of insurance policy.58 Osteoma Osteomas are benign tumors consisting of mature compact or cancellous bone. They may arise on the surface of bone (periosteal osteomas) or centrally within the bone (endosteal osteomas).61 They are often discovered as asymptomatic radiopacities. Osteomas are most commonly discovered during the second and fifth decades of life, although they have beeoted in all age groups.Males appear to be affected more frequently than females. Gardner’s syndrome is an autosomal dominant condition in which patients have intestinal polyposis, multiple osteomas (usually endosteal) of the jaws, fibromas of the skin, epidermal cysts, impacted teeth, and odontomas.62–65 The specific gene associated with the condition has now been identified on the long arm of chromosome 5.66–68 Many cases of incomplete manifestation of the syndrome have been reported. The clinical significance of this syndrome is that the intestinal polyps, which frequently occur in the colon and rectum, are premalignant and have a very high rate of malignant transformation. The associated osteomas are often found in the jaws, particularly in the angle region of the mandible, as well as the facial bones and long bones. It has been suggested that any patient with multiple mandibular osteomas should be investigated for the possibility of
Synovial Chondromatosis and Osteochondroma
Both synovial chondromatosis and osteochondroma are conditions that occur in the temporomandibular joints and may be considered variants of the chondroma and osteoma. In synovial chondromatosis there is a proliferation of small particulate, generally unattached chondromas within the confines of the joint capsule. Although most frequently found in the knee, they have been reported in most joints. Wellrecognized cases have occurred in the temporomandibular joints with symptoms normally consisting of pain and swelling but most often with deviation of the mandible toward the unaffected side (Figure 31-11).69,70 The etiology is unknown, but trauma has been suggested.71 When these lesions become symptomatic, they should be removed via a standard preauricular approach. Since it is felt that they arise from metaplasia within the synovial lining cells of the joint, it is often advocated that the lining be removed at the same time.72 Cases have been reported in which up to 200 of these bodies were present within the temporomandibular joint (Figure 31-12).
Following removal, recurrence has not been reported. The osteochondroma is felt to be a benign lesion that arises predominantly in long bones from a herniation of cartilage through the epiphyseal plate. It tends to present with a predominantly osseous core with a cartilaginous cap. The lesion becomes symptomatic when function is affected, for example, a malocclusion or mandibular asymmetry develops (Figure 31-13).
Cases have been reported in the mandibular condyle.73 Cases in the temporomandibular joints appear identical in all respects to lesions in other bones of the body.However, the association with the epiphyseal plate that occurs in the long bones is not present in the temporomandibular joint. On magnetic resonance imaging it appears as an extraneous appendage to the temporomandibular joint and is usually more radiopaque than the surrounding mandible (Figure 31-14).
Treatment is symptomatic; when symptoms occur, localized excision is recommended via the normal temporomandibular approach. Recurrence has been reported but is unusual.74–77
Aggressive Mesenchymal Tumors of Childhood
It is recognized that children and young adults can develop an aggressive and rapidly growing tumor of bone, which, although often having a benign mesenchymal appearance, nevertheless behaves very aggressively. The exact nature of these lesions remains unknown, but many have been classified as desmoplastic fibromas, which is the hard tissue equivalent of fibromatosis in the soft tissues. Any bone can be affected including the jaws. The etiology and pathogenesis are in doubt since their aggressive behavior suggests a neoplastic process, but genetic, endocrine, and traumatic factors have also been suggested. Most occur in persons under the age of 20 years, and there is no gender predilection. The mandible is affected more frequently than the maxilla.78 Radiographically a unilocular or multilocular radiolucency is noted with poorly defined margins, cortical perforation, and root resorption often being present (Figures 31- 15 and 31-16).
Histologically the lesion consists of interlacing bundles in a whirled aggregate of collagenous tissue with elongated and spindle fibroblasts. Hypocellularity is often present. However, atypia and mitotic features are not found. Osteoid material is not produced by this lesion. In treating this lesion, the adage “treat the biology, not the histology” is of paramount importance. Although the lesion looks benign histologically, it often behaves aggressively,79 and the appropriate treatment is aggressive surgery, which often involves mandibular or maxillary resection (Figure 31-17).
This is psychologically difficult for the surgeon to perform in a young child without a histologic diagnosis of malignancy, but the recurrence rate is very high following more conservative procedures. For lesions in inaccessible areas such as the base of the skull, radiation therapy and/or chemotherapy has been attempted with variable degrees of success.
Lesions Containing Giant Cells
There are a number of lesions that occur in the jaws that contain giant cells within them. Their relationship to each other, however, is ill defined. Histologically all of the giant cell lesions appear similar, if not identical, and they usually cannot be distinguished on light microscopy alone. The clinical history, immunohistochemistry, or genetic markers have to be used to differentiate the lesions.
Central Giant Cell Granuloma
Central giant cell granuloma is a lesion occurring almost exclusively in the jaws. (A similar lesion has been described in the small bones of the fingers and toes, but its relationship to the central giant cell granuloma is unknown.82) Although not normally considered an odontogenic lesion, the fact that it only occurs in the jawbones probably indicates some relationship to the teeth or tooth-bearing structures. It occurs primarily in the anterior parts of the jaws in people in the second and third decades of life, but it has been recorded in all sites at all ages. Its histogenesis remains speculative. When first described it was called a reparative giant cell granuloma, 83–85 and it was considered a reparative lesion that was essentially self-healing. There was little evidence of this, however, and only oblique references to its selfhealing properties can be found. Worth showed in a study of a number of nontreated lesions that resolution often did occur as seen radiographically; even when the lesions did not resolve completely radiographically, only a fibrous scar was noted on surgical exploration.86 The current consensus, however, is that these are not reparative lesions and that if they are not treated, they are progressive. Most appear to follow a fairly benign course, but more aggressive lesions have beeoted.87–89 The true nature of the central giant cell granuloma remains speculative. It has been suggested that it may be an inflammatory lesion, a reactive lesion, a true tumor, or an endocrine lesion. It may behave most like a reactive lesion. Older theories about the origin of these lesions suggested that they may be derived from the odontoclasts that were responsible for resorption of the deciduous teeth; this was said to explain why they are normally found in areas where deciduous teeth were present and are found after the deciduous teeth have resorbed. Radiographically the central giant cell granuloma can take a number of forms from a well-defined radiolucency, a more ill-defined radiolucency or a multilocular radiolucency. Teeth can be displaced by the lesion, although resorption of teeth is uncommon (Figures 31-18 and 31-19).
Histologically these granulomas contain focal arrangements of giant cells within a vascular stroma with thin-walled capillaries adjacent to the giant cells. There is a spindle cell stroma. Immunohistochemistry has shown that the giant cells are in fact osteoclasts,90 and the spindle cells are probably the cells of origin of this lesion.91 Treatment is usually surgical and consists of local curettage, which is usually curative.92 However, there is a 15 to 20% recurrence rate, and if the lesions are large, even conservative curettage may involve the loss of many teeth and possibly the inferior alveolar nerve in the mandible, and it may have sinus and nasal implications in the maxilla. With the aggressive variants, more aggressive surgery has been suggested including mandibular resection and appropriate reconstruction.93 Since the central giant cell granuloma and the brown tumor of hyperparathyroidism cannot be separated histologically, it is advocated that hyperparathyroidism be excluded from the diagnosis by serum calcium, phosphate, and parathormone and parathormone-related protein assays in all but the single small and more benign lesions.94 A number of nonsurgical treatments have been suggested, all of which have their advocates. Intralesional steroids (usually triamcinolone injected into the lesion once per week for 6 wk) have been advocated and have shown some success.95–98 Their mode of action is unknown, but they may work by suppressing the inflammatory component of the lesion. They are probably best reserved for smaller lesions that can be more easily treated by intralesional injections (Figure 31-20).
Calcitonin given by subcutaneous injection has also been advocated and has met with some success (Figure 31-21)
.
The theory behind this treatment is that the lesion may be caused by an as-yet undiscovered parathormone-like hormone, and that the use of calcitonin antagonizes its action and allows the lesion to heal. Since some of the giant cells have been shown to have calcitonin receptors on them, this may explain calcitonin’s effectiveness.94 α-Interferon given by subcutaneous injection has also been advocated in the treatment of the central giant cell granuloma and has again met with some success. 106,107 The rationale for this therapy is that the antiangiogenic action of the α-interferon suppresses the angiogenic component of this lesion, causing healing to occur. In most cases surgery is still required after the α-interferon treatment, but it may be less radical surgery and there may be a smaller chance of recurrence. It has again been suggested that the central giant cell granuloma may, in fact, be a self healing lesion, with the natural healing process stimulated by the nonsurgical therapy employed.105
Giant Cell Tumor
The giant cell tumor is normally found in the long bones and its presence in the jaws is not universally accepted; if it does occur, it is extremely rare. This lesion is an aggressive one and is felt by some to be a variant of a low-grade osteosarcoma. The recurrence rate after local curettage is high, and the appropriate treatment is in doubt. Some authorities advocate local curettage, whereas some have advocated resection. Histologically it is very similar to the central giant cell granuloma, except that the giant cells are larger with more nuclei, and they are more evenly spread throughout the lesion and not as focally placed as in the central giant cell granuloma. However, in any particular case it may be extremely difficult to make this distinction.45
Hyperparathyroidism
In hyperparathyroidism (primary, secondary, or tertiary), calcium is mobilized from the bones into the blood stream to maintain homeostasis in the face of increased renal excretion. Mobilization from bone takes place focally and produces lesions in the bones (including the jaws) that are known as brown tumors because of their fairly distinctive coloration on surgical exploration.108 Clinically and histologically they are identical to the central giant cell granuloma and cannot be distinguished on either clinical or histologic grounds (Figure 31-22).
Therefore, whenever a lesion such as this is recurrent, aggressive, or multiple, hyperparathyroidism must be excluded by means of serum calcium, phosphate, and parathormone and parathormone-related protein assays. If these confirm a diagnosis of hyperparathyroidism, it should be treated appropriately. The lesions normally resolve without any further treatment being required.
Cherubism Cherubism is a familial genetically dominant condition first described by Jones in a family in 1933.109 Affected family members have multiple lesions mainly affecting the facial bones. Because of the involvement of the maxilla and orbital floor, the face has a rounded appearance and the eyes tend to look upward, giving the patient a cherubic appearance (Figure 31-23).
The genetic defect in this condition has been identified on chromosome 4p16.3.110,111 Expression is variable, with some patients having subclinical lesions discovered only on radiographs and some having extensive and clinically obvious lesions. Spontaneous mutations also occur. Radiographically the lesions appear honeycombed and can be very extensive. Teeth are often displaced, and in active periods the lesions are extremely vascular (Figures 31-24 and 31-25).
Histologically the lesions are very similar to central giant cell granuloma, with focal accumulations of giant cells in a spindle cell matrix. Perivascular cuffing is often present, and in some cases can be used to differentiate the two lesions. Because of its histologic similarity to central giant cell granuloma, calcitonin has been used in an attempt to cause resolution, but it has not met with success, suggesting that they are, in fact, different lesions.112 Treatment of cherubism is usually conservative and expectant and into the teenage years is devoted to trying to aid eruption of the teeth, which is often abnormal. Later it is directed toward cosmetic recontouring of the affected bones. The lesions normally become less active and less vascular toward the end of the second decade and into the third decade, and it is at this time that most cosmetic remodeling is carried out.
Aneurysmal Bone Cyst
Aneurysmal bone cyst is most commonly found in the jawbones and appears to be a combination of a sinusoidal vascular lesion with a giant cell component. Radiographically the lesion appears as a wellcircumscribed soap bubble–type lesion (Figure 31-26).
Histologically the giant cell component resembles the central giant cell granuloma, whereas the vascular component is thin-walled sinusoids. Some authorities consider this to be a vascular variant of a central giant cell granuloma; others consider it a separate lesion. It responds well to moderately aggressive curettage, although hemorrhage can be a problem. Recurrences are rare. Vascular Malformations Vascular malformations can occur anywhere in the body and are felt to be developmental lesions, which can occur in soft tissue or bone. Central vascular malformations of the jaws are a rare but welldocumented entity. They are in contrast to the true hemangioma, which is a neoplasm of vascular endothelium and is normally present at birth, often enlarges, and then frequently involutes.113 The vascular malformation generally is not present at birth, appears later, and does not involute. Vascular malformations can take a number of forms. The most practical classification is to divide them into high-flow and low-flow vascular malformations. The high-flow vascular malformations are either arterial lesions or arteriovenous fistulas. The low-flow malformations are mainly venous iature. The clinical significance of a vascular malformation is that a central high-flow vascular malformation can cause torrential hemorrhage when surgical intervention ensues. This has been fatal on occasion.114 Many of these lesions are asymptomatic and may even be difficult to detect preoperatively on radiographs. If there is a clinical presentation, it is often a slow-growing asymmetric expansile lesion of the jaw, and if it is high flow, it may be associated with a bruit. Radiographically a high-flow malformation may appear as an irregular poorly defined soap bubble–type lesion, which may cause resorption of the roots of teeth and does not normally cause nerve involvement (Figure 31-27).
Lowflow malformations are similar but are often somewhat better defined and may contain calcifications or phleboliths within them. The presence of phleboliths is diagnostic of a low-flow malformation. Diagnosis is usually confirmed by computed tomography. To avoid the possibility of inadvertently carrying out a tooth removal or a biopsy in the presence of a high-flow malformation, a diagnostic needle aspiration should be carried out preoperatively. If bright red blood under pressure is encountered, surgery should be abandoned. Since the radiographic and clinical appearances of a vascular malformation are not diagnostic, the differential diagnosis normally includes a number of odontogenic and nonodontogenic lesions, including the central giant cell granuloma, the aneurysmal bone cyst, ameloblastoma, odontogenic keratocyst, and odontogenic myxoma. All of these lesions should undergo needle aspiration prior to biopsy or surgical treatment to rule out a highflow vascular malformation. When a vascular malformation is suspected or diagnosed, selective angiography is normally performed via a femoral approach (Figure 31-28).
If a high-flow vascular malformation is diagnosed, treatment is normally preoperative embolization followed by wide resective surgery. The embolization can involve a number of materials, including muscle, polyvinyl, pellets, and platinum coils, which are inserted via the angiography catheter or on direct puncture. On entering the lesion they unwind and expand (Figure 31-29).
Postembolization angiography carried out immediately after the embolization normally shows a diminution in blood flow to the lesion. However, because of the powerful angiogenic effect of these lesions (probably by production of angiogenesis growth factor), reestablishment of smaller collateral vessels usually occurs within a few days, and it is often impossible to reembolize these smaller collateral vessels. Therefore, definitive surgery should be carried out within a small number of days of embolization. Definitive surgery normally takes the form of resection under hypotensive anesthesia with adequate resuscitative measures available.117–119 Following resection appropriate reconstruction can be performed. This can include the re-insertion of the resected portion of bone after curettage, thinning, perforation, and simultaneous bone grafting (Figure 31-30).
Other approaches such as injection of a variety of substances into the lesion including glue, fibrin gel, and platinum coils,115 for example, have been attempted; also, case reports exist of lesions being treated by means of local curettage following embolization, but this is not normally recommended. Low-flow or venous malformations are not as life-threatening and are normally treated with direct puncture and an attempt to thrombose the lesion by intralesional injection of a variety of agents, including sclerosing agents, an absorbable gelatin sponge, and platinum coils. This may bring about thrombosis, allowing the necessary dental or surgical treatment to be carried out. Often mandibular resection is not necessary but, rather, a local surgical procedure.
Langerhans Cell Histiocytosis
Langerhans cell histiocytosis is the term currently employed for what was previously known as histiocytosis X, and before that the three separate conditions Letterer-Siwe disease, Hand-Schuller-Christian disease, and eosinophilic granuloma. Lichtenstein first suggested that the three diseases were related and that the common factor was the presence of histiocytes.120 The cells of origin of this disease have now been identified as the Langerhans cells, which are dendritic cells in the skin and mucosa that have a macrophage-like function. At the present time what causes these cells to proliferate in a clonal fashion with phenotypic evidence of activation and give rise to Langerhans cell disease is unknown.121 The nature of this disease also eludes us. Some recent studies have suggested that it may have some of the properties of a tumor or have a viral etiology. 122,123 Other studies propose that it may be a response to an overwhelming allergenic challenge, and they report cases of eosinophilic granuloma that have resolved spontaneously, further adding to the puzzle. 121,124 The Histiocyte Society has attempted to define all of the histiocytic diseases in a logical manner,125 and Letterer-Siwe disease is now felt to represent the acute disseminated form of Langerhans cell histiocytosis, whereas Hand-Schuller-Christian disease represents the chronic disseminated form, and eosinophilic granuloma represents the chronic localized form. The acute disseminated form usually affects young children. It is multisystem iature, affecting the skin, bones, and internal organs (especially lungs and liver), and is frequently fatal. Treatment is chemotherapy. The chronic disseminated form of the disease is classically associated with a triad of punched-out bone lesions (often affecting the skull and jaws), diabetes insipidus (owing to posterior pituitary involvement), and exophthalmos (owing to deposits in the posterior orbit). This normally affects an older age group, often in the second and third decades but sometimes much older. The bone lesions often affect the jaws. Although they usually appear as fairly well-defined punched-out radiolucencies (Figure 31-31),
they can also be less well defined and can affect the apices of the teeth only and lead to a possible differential diagnosis of periapical infection. A frequent aspect of presentation is loose teeth; radiographically they often appear as “floating teeth” (Figure 31-32).
The treatment of the chronic disseminated form of the disease is variable, and for well-circumscribed lesions can consist of local curettage. However, for more aggressive forms, chemotherapy is frequently employed as well. Low-dose radiation therapy has also been used on isolated lesions, and it does remain one of the very few indications for low-dose radiation therapy, often in the region of a few hundred centigray. The chronic localized form of the disease is commonly found in the jaws and usually shows as a well-defined radiolucency, often in the bicuspid region and more frequently in the mandible. Differential diagnosis in this case includes any fairly well-defined radiolucency. Treatment usually consists of aggressive local curettage, and the recurrence rate is low. Teeth are sacrificed as necessary. Intralesional steroids have also been employed with some success, and cases of spontaneous regression have been reported.124,126 It is generally felt that the occurrence of Langerhans cell histiocytosis is sporadic, but clusters have beeoted and there are a number of reports of a familial incidence. 121 I have seen the disease in a father and son. The father was diagnosed with the chronic disseminated form of the disease at age 53 years (see Figure 31-31), whereas his son died from the acute disseminated form of the disease at age 11 years.
Nonodontogenic Cysts of the Jaws
In this section the following are discussed: globulomaxillary lesion, nasolabial lesion, median mandibular cyst, nasopalatine duct cyst, all of which are also know as fissural cysts, traumatic bone cyst, and Stafne’s bone cyst. Aneurysmal bone cyst has been discussed under “Lesions Containing Giant Cells,” above. Globulomaxillary Lesion Globulomaxillary lesion was initially defined as a globulomaxillary cyst and was felt to be a fissural cyst caused by retained epithelial remnants at the fusion of the maxillary process with the globular process. It is normally found in the second or third decade. In the classic description, the lesion presents as a pear-shaped well-defined radiolucency in the maxilla between the lateral incisor and canine. Associated teeth are classically vital, and the lesion is lined by cystic epithelium with occasional globular or ciliated epithelia. Current thinking is that although this lesion does exist as a radiographic and clinical entity (Figure 31-33),
it is not, in fact, a fissural cyst since the proposed embryonic derivation is now known to be flawed and the supposed fusion line does not exist. It is felt that most lesions previously diagnosed as globulomaxillary cysts caow be reclassified as odontogenic keratocysts, radicular cysts, periapical granulomas, lateral periodontal cysts, central giant cell granulomas, calcifying odontogenic cysts, and odontogenic myxomas.45 Tooth roots may be diverged by the lesion, and biopsy is usually necessary to confirm the diagnosis and enable appropriate surgical treatment to be carried out. Treatment normally consists of enucleation and curettage.
Nasolabial Cysts
The nasolabial cyst was felt to be the soft tissue counterpart of the globulomaxillary cyst. Again, it was felt to be formed at the lines of fusion of the globulomaxillary processes. Similarly, this lesion does exist, but its true origin remains in doubt. It could be derived from remnants that form the nasolacrimal duct. This cyst manifests itself as a soft tissue swelling in the lateral aspect of the upper lip, fairly high in the sulcus (Figure 31-34).
The cyst lining is typically a pseudostratified columnar type with numerous goblet cells. Treatment is local excision.
Median Mandibular Cyst
Median mandibular cyst is a rare cyst found in the midline of the mandible. It was originally felt to form at the line of fusion of each half of the mandibular arch. Again, the embryologic theory behind this lesion is no longer felt to be applicable, and it is believed that those lesions found in the anterior mandible represent some other type of odontogenic cyst or tumor.
Nasopalatine Duct Cyst
Nasopalatine duct cyst is also known as incisive canal cyst and is generally located on the palatal end of the nasopalatine duct. It frequently presents as a soft swelling behind the upper anterior teeth. It is felt to be derived from the epithelial remnants of the paired embryonic nasopalatine ducts within the incisive canal, and that either infection or trauma may be the stimulus for the cells to proliferate and form a cyst. These cysts appear to occur more frequently in males than in females and are commonest in the fourth to sixth decades of life.Most cases are asymptomatic and are either found by chance on radiograph or present as a soft tissue swelling in the palate. Radiographically this cyst appears as a well-defined radiolucency found in the midline of the anterior palate (Figure 31-35).
In many patients the nasopalatine duct can be identified on an occlusal radiograph; the question then arises as to when the diagnosis of nasopalatine duct cyst should be entertained. A fairly arbitrary cutoff point of 7 mm has been suggested— if the nasopalatine duct appears to be > 7 mm in diameter, the presence of a cyst should be suspectedDiagnosis is by biopsy, which normally shows a pseudostratified columnar epithelium lining. Treatment, if required, is surgical and consists of local curettage. This almost inevitably requires the sacrifice of the nasopalatine vessels and nerves, which results in a small area of anesthesia over the anterior palate behind the upper incisor teeth. Some patients (particularly more elderly patients) find this particularly troublesome in the articulation of some words. Recurrence rate is very low following treatment.
Bilozetskyi Ivan
