16 Nonodontogenic Intraosseous Lesions
Tori and Exostoses
• Tori: 2% to 10% of adults; exophytic, hard, uninodular or multinodular bony masses covered by mucosa that may be ulcerated from trauma; torus palatinus and torus mandibularis on the midline of palate and lingual mandible (usually bilateral and symmetric), respectively (Fig. 16-1, A and B); often site of bisphosphonate-associated osteonecrosis
• Exostoses: 27% of adults; male predilection (5 : 1); outgrowths of bone, nodular or sessile frequently on buccal aspects of mandible and maxilla or ascending arch of the palate and more than 90% having concurrent tori (see Fig. 16-1, C and D); exostoses possibly show rapid growth in some patients
FIGURE 16-1 A, Torus mandibularis: bilaterally symmetric sessile bony masses on the lingual aspect of the mandible. B, Torus palatinus: multinodular bony masses on the midline of the palate. C, Palatal exostosis: bony mass on the ascending arch of palate. D, Buccal exostosis: unilateral sessile bony mass on the buccal aspect of the maxilla.
• Dense bone island, bone scar, or idiopathic osteosclerosis is not exophytic and is an asymptomatic intraosseous radiopacity not related to teeth that is discovered on routine radiography (Fig. 16-4, A); biopsy is not necessary unless the lesion is radiographically progressive; histopathology is similar and bone is often sclerotic.
• Condensing osteitis is similar to idiopathic osteosclerosis but is found at or very close to the apices of teeth and is likely reactive to chronic occlusal trauma or low-grade inflammation or odontogenic infection; biopsy is not necessary (see Fig. 16-4, B).
• True osteomas are associated with Gardner syndrome (autosomal dominant condition associated with mutation in the APC gene and development of colonic polyps and carcinoma, desmoid tumors, supernumerary teeth, and skin cysts).
FIGURE 16-4 A, Idiopathic osteosclerosis: radiopacities in the left mandible not related to apices of teeth. B, Condensing osteitis: poorly demarcated uniform radiopacity around the roots of endodontically treated left mandibular first molar.
(A, Courtesy of Dr. Thomas Mone, private practice, Braintree, Mass.)
Fibro-osseous lesions are a heterogeneous group of lesions composed of osseous dysplasias, inflammatory conditions, and neoplasms, characterized by a proliferation of fibroblast-like cells and deposition of osseous or cementum-like material. Their histologic features overlap, depending on the stage in which the biopsies are obtained, and an accurate diagnosis can be rendered only after correlation of clinical and radiographic data. Differentiation between lesions is essential so that appropriate therapy can be instituted. The lesions considered here are fibrous dysplasia, cemento-osseous dysplasia, cemento-ossifying fibroma, aggressive ossifying fibroma, and familial gigantiform cementoma. Nomenclature for these lesions continues to evolve.
FIGURE 16-5 Fibrous dysplasia. A, Periapical films showing ground-glass appearance of the right maxilla (top panel) and normal trabeculation on the left (bottom panel). B, Ground-glass appearance of mandibular bone.
(A, Courtesy of Dr. Bernard Friedland, Harvard School of Dental Medicine, Boston, Mass; B, Courtesy of Dr. Stanley Hirsch, Case Western Reserve University, Cleveland, Ohio.)
FIGURE 16-6 Focal cemento-osseous dysplasia. A, Variant: periapical cemento-osseous dysplasia. Radiolucency at the apices of vital mandibular anterior teeth with faint opacities. B, Circumscribed radiolucency with sclerotic rim and central calcification around the distal root of the right mandibular first molar.
(Courtesy of Dr. Rafik Abdelsayed, Medical College of Georgia, School of Dentistry, Augusta, Ga.)
(Courtesy of Dr. Bonnie Padwa, Harvard School of Dental Medicine, Boston, Mass.)
(From Abdelsayed RA, Eversole LR, Singh BS, Scarbrough FE. Gigantiform cementoma: clinicopathologic presentation of 3 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001;91:438-444.)
Fibrous dysplasia is associated with a mutation in the GNAS gene that results in alterations in proliferation and differentiation of preosteoblasts; there are monostotic (85% to 90% of cases) and polyostotic types; the latter is seen in McCune-Albright syndrome and is often associated with endocrinopathies and skin pigmentation. The other conditions have not been shown to be consistently associated with gene mutations, although familial gigantiform cementoma is an inherited disorder.
• Fibrous dysplasia consists of a proliferation of benign fibrous tissue and either small, delicate, or curvilinear trabeculae of woven bone in early lesions, or thicker and denser trabeculae of woven or lamellar bone in mature lesions; osteoblastic rimming and occasional osteoclasts may be seen focally, especially in early and inflamed lesions; there is variable vascularity (Figs. 16-11 and 16-12); aneurysmal bone cyst–like areas may be seen.
• Cemento-osseous dysplasia consists of a cellular proliferation of spindled benign fibroblast-like cells and deposition of osteoid, woven bone, cementum droplets, or a mixture thereof; mature lesions consist of a mass of cementum that has a rounded, globular appearance with few cementocytes (sclerotic cemental mass) (Figs. 16-13 to 16-15); cells that rim bone and cementum are often osteoblast-like.
• Cemento-ossifying fibroma consists of cellular proliferation of spindled fibroblast-like cells that deposit osteoid, trabeculae of woven bone, and cementum droplets in varying proportions; osteoblastic rimming is common (Fig. 16-16).
• Aggressive ossifying fibroma (desmo-osteoblastoma) consists of a cellular proliferation of plump and stellate fibroblast-like cells with large, slightly atypical nuclei, clusters of multinucleated giant cells, and fresh hemorrhage; trabecular variant has abundant woven bone surrounding large osteocytes with many osteoblasts (Figs. 16-17 and 16-18); psammommatoid variant has many basophilic cementum droplets or psammomatoid bodies, most of which are of uniform size (Fig. 16-19); this subtype appears similar to familial gigantiform cementoma.
FIGURE 16-11 Fibrous dysplasia. A, Delicate trabeculae of bone in fibrous stroma, abutting the mucosa with no intervening cortical lamellar bone. B, Delicate interlacing trabeculae of woven bone in fibrous stroma. C, Woven bone with plump osteocytes, focal osteoblastic rimming, and mild chronic inflammation (inset).
FIGURE 16-12 Fibrous dysplasia in 50-year-old patient. A, Thicker trabeculae of bone with more densely fibrous tissue. B, Focal osteoblastic rimming and osteoclastic activity. C, Polarized light reveals parallel delicate lamellae.
FIGURE 16-13 Focal cemento-osseous dysplasia. A, Nonencapsulated lesion abutting normal lamellar bone (top). B, Proliferation of spindle cells with cementum droplets and woven bone. C, Plump spindle cells with acellular cementum droplets and woven bone. D, Polarized light reveals short collagen bundles.
FIGURE 16-14 Focal cemento-osseous dysplasia. A, Mature lesion with large sclerotic cemental mass adjacent to cellular zone and lamellar cortical bone. B, Focal area of cellular spindle cell proliferation adjacent to dense, hypocellular osteocementum. C, Spindle cells and globular cementum with eosinophilic border of osteoid-like material.
FIGURE 16-15 Focal cemento-osseous dysplasia. A, Mature lesion composed of masses of globular hypocellular cementum with many resting and reversal lines (sclerotic cemental mass). B, Acellular globular cementum (sclerotic cemental mass).
FIGURE 16-16 Central cemento-ossifying fibroma. A, Proliferation of spindle cells with deposition of osteoid, woven bone, and cementum with focal capsule (left, against rim of cortical bone). B, Trabeculae of woven bone with plump osteocytes and acellular cementum droplets and woven bone. C, Cementum droplet with surrounding benign fibroblasts.
FIGURE 16-17 Aggressive ossifying fibroma, trabecular type. A, Cellular proliferation of spindle cells with osteoid and woven bone formation. B, Osteoid, woven bone, spindle cells, and giant cells. C, Osteoid and woven bone containing plump osteocytes and osteoblasts surrounded by spindle cells. D, Plump osteocytes, osteoblasts, and cellular stroma with spindled and stellate cells. E, Early aneurysmal bone cystlike areas.
FIGURE 16-18 Aggressive ossifying fibroma, trabecular type. A, Cellular proliferation of spindle cells with osteoid and woven bone formation. B, Osteoid formation and reactive or residual bone at left; areas of loose myxoid stroma within cellular areas. C, Osteoid and woven bone with plump osteocytes and osteoblasts; stellate and spindle cells within stroma. D, Clusters of multinucleated giant cells within myxoid stroma.
FIGURE 16-19 Aggressive ossifying fibroma, psammomatoid type. A, Spindle cell proliferation packed with globular cementum droplets and round or ovoid fragments of woven bone. B, Benign spindle cells with cementum droplets and some woven bone. C, Both psammomatoid cementum droplets and small trabecular fragments of bone.
• Osteoblastoma shows a proliferation of osteoblasts composed of large cells with eccentric nuclei, often multilayered against the bone, osteoclasts on the same trabeculae, and prominent ectatic vessels (Fig. 16-20); bone is basoophilic, sometimes with many resting and reversal lines.
• Cemento-osseous dysplasia: no treatment necessary; however, sclerotic masses of cementum are hypovascular and extractions may lead to osteomyelitis; simple bone cysts are associated with long-standing lesions (Fig. 16-21).
El-Mofty S. Psammomatoid and trabecular juvenile ossifying fibroma of the craniofacial skeleton: two distinct clinicopathologic entities. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002;93:296-304.
Rossbach HC, Letson D, Lacson A, et al. Familial gigantiform cementoma with brittle bone disease, pathologic fractures, and osteosarcoma: a possible explanation of an ancient mystery. Pediatr Blood Cancer. 2005;44:390-396.
Su L, Weathers DR, Waldron CA. Distinguishing features of focal cemento-osseous dysplasias and cemento-ossifying fibromas. I. A pathologic spectrum of 316 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1997;84:301-309.
Su L, Weathers DR, Waldron CA. Distinguishing features of focal cemento-osseous dysplasia and cemento-ossifying fibromas. II. A clinical and radiologic spectrum of 316 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1997;84:540-549.
Paget Disease of Bone (Osteitis Deformans)
• Affects 1% to 2% of the white population (usually men) older than age 55, with highest frequency in the United Kingdom and lowest frequency in Asia; familial history in 15% to 40% of cases; first sign may be bone pain and headaches; deposition of bone around skull foramina may lead to neurologic symptoms, such as hearing or visual loss; poor fit of dentures or hats and spacing between teeth may occur from expansion of skull and jaw bones.
• Radiographs in early stages show osteoporotic changes; in the mixed stage, there is thickening of bones with mixed radiolucency and radiopacity (“cotton wool appearance”) with bone sclerosis being more marked as disease progresses (Fig. 16-22).
FIGURE 16-22 Paget disease of bone (osteitis deformans). A, Sagittal CT shows thickened cranial bones, maxilla and mandible, and an increase in bone density. B, Occlusal radiograph shows mottled radiolucency/opacity of the mandible.
(From White SC, Pharoah MJ: Oral Radiology: Principles and Interpretation. 6th ed. St. Louis, Mosby, 2009.)
Both genetic and environmental influences have been identified. Some cases are inherited in an autosomal dominant fashion; sequestosome, a gene that encodes p62 (a protein involved in NFκB signaling) is present in 20% to 50% of inherited and 5% to 20% of sporadic cases; increased number and activity of osteoclasts leads to initial resorption of bone and osteoporotic appearance (osteoclastic stage), followed by compensatory but overproduction of lamellar bone in a haphazard fashion with prominent vascularity (mixed osteoclastic-osteoblastic stage), and finally, “burnt out” stage with fibrosis of connective tissue; the role of paramyxovirus and other viruses (such as measles and distemper virus) as a trigger is controversial.
• The haphazard deposition of bone results in a mosaic pattern and many resting and reversal lines; numerous giant, irregular-shaped, hypernucleated osteoclasts are present; many osteoblasts are noted on surface of bone trabeculae, and there is marked hypervascularity in the mixed stage (Fig. 16-23).
FIGURE 16-23 Paget disease of bone (osteitis deformans). A, Anastomosing trabeculae of woven bone with many osteoclasts and prominent dilated vessels. B, Giant hypernucleated osteoclasts, dilated vessels, and bony trabeculae with resting and reversal lines. C, Many osteoblasts are present laying down osteoid.
(A, Courtesy of Dr. Charles E. Tomich, Indiana University of School of Dentistry, Indianapolis, Ind.)
Central Giant Cell Granuloma (Aggressive and Nonaggressive Giant Cell Lesion, Central Giant Cell Lesion, Central Giant Cell Reparative Granuloma)
Data suggest that the nonaggressive and aggressive giant cell granulomas and lesions of the maxillofacial complex have similar clinical presentations and treatment outcomes when compared, respectively, with the nonaggressive and aggressive axial-appendicular giant cell lesions; therefore, they may represent the same disease process.
• Aggressive type is less than 5 cm, recurs (primary criteria) or shows at least three of the following secondary criteria: rapid growth, root resorption, tooth displacement and thinning, or perforation of the cortical plate (see Fig. 16-24, B).
FIGURE 16-24 A, Nonaggressive central giant cell granuloma. Panoramic radiograph shows radiolucency at the apex of right mandibular second molar. B, Aggressive central giant cell granuloma. Recurrent tumor of right maxilla involving maxillary and ethmoid sinuses and nasal cavity.
(A, Courtesy of Dr. Leonard B. Kaban and W. C. Guralnick, Harvard School of Dental Medicine and Massachusetts General Hospital, Boston, Mass; B, Courtesy of Dr. Leonard B. Kaban and Dr. Maria Troulis, Harvard School of Dental Medicine and Massachusetts General Hospital, Boston, Mass.)
Cells are derived from mesenchymal stromal cells that differentiate along the monocyte-macrophage-osteoclast lineage. No consistent genetic abnormalities have been noted, although frequent telomeric associations have been reported in giant cell tumor of bone.
• Proliferation of mononuclear cells and clusters of multinucleated osteoclast-like giant cells with abundant fresh hemorrhage, siderophages, and reactive osteoid and woven bone formation; giant cells have 20 to 30 nuclei; mononuclear cells often show mitotic activity (Figs. 16-25 and 16-26).
• Most giant cells and approximately 10% of mononuclear cells stain for tartrate-resistant acid phosphatase, CD68, cathepsin, and MMP-9; in situ hybridization studies show mRNA for osteoprotegrin within giant cells and RANK and RANKL within stromal cells; both show variable staining for glucocorticoid and calcitonin receptors.
FIGURE 16-25 Central giant cell granuloma. A, Nodules of giant cells, fibrosis, and hemosiderin deposits. B, Nodular aggregates of giant cells and spindled mononuclear cells with fibrosis and hemosiderin deposits. C, Mononuclear cells with benign nuclei and osteoclast-like giant cells with hemorrhage.
• Giant cell tumors of bone tend to have sheets rather than clusters of giant cells, which contain more nuclei, although distinction may be difficult; differences in histopathology may predict more aggressive behavior.
• Curettage, excision, resection, intralesional steroid injections, calcitonin nasal spray; enucleation and/or tumor debulking with adjuvant interferon-α therapy have been successful in resolving lesions completely (Fig. 16-27).
FIGURE 16-27 Aggressive central giant cell granuloma (same patient as in Figure16-24, B): coronal CT exhibits resolution of right maxillary lesion 3 years after enucleation and 2 years after completion of treatment with systemic interferon therapy.
(Courtesy of Dr. Leonard B. Kaban and Dr. Maria Troulis, Harvard School of Dental Medicine and Massachusetts General Hospital, Boston, Mass.)
Gebre-Medhin S, Broberg K, Jonson T, et al. Telomeric associations correlate with telomere length reduction and clonal chromosome aberrations in giant cell tumor of bone. Cytogenet Genome Res. 2009;124:121-127.
Resnick CM, Margolis J, Susarla SM, et al. Maxillofacial and axial/appendicular giant cell lesions: unique tumors or variants of the same disease? A comparison of phenotypic, clinical, and radiographic characteristics. J Oral Maxillofac Surg. 2010;68:130-137.
Vered M, Buchner A, Dayan D. Immunohistochemical expression of glucocorticoid and calcitonin receptors as a tool for selecting therapeutic approach in central giant cell granuloma of the jawbones. Int J Oral Maxillofac Surg. 2006;35:756-760.
• Condition occurs most frequently in first decade; bilateral multiloculated radiolucencies of the posterior mandible and ascending ramus often result in tooth displacement, delayed tooth eruption, and loosening of teeth (Fig. 16-28); involvement of the maxilla causes eyes to turn upward, resembling a cherub; a unilateral lesion may be the first presentation.