Benign fibro-osseous lesions of the craniofacial complex. A review

Abstract

Benign fibro-osseous lesions of the craniofacial complex are represented by a variety of disease processes that are characterized by pathologic ossifications and calcifications in association with a hypercellular fibroblastic marrow element. The current classification includes neoplasms, developmental dysplastic lesions and inflammatory/reactive processes. The definitive diagnosis can rarely be rendered on the basis of histopathologic features alone; rather, procurement of a final diagnosis is usually dependent upon assessment of microscopic, clinical and imaging features together. Fibrous dysplasia and osteitis deformans constitute two dysplastic lesions in which mutations have been uncovered. Other dysplastic bone diseases of the craniofacial complex include florid osseous dysplasia, focal cemento-osseous dysplasia and periapical cemental dysplasia, all showing a predilection for African descent individuals; although no specific genetic alterations in DNA coding have yet to be uncovered and most studies have been derived from predominant high African descent populations. Ossifying fibromas are neoplastic lesions with four subtypes varying with regard to behavior and propensity for recurrence after surgical excision. The clinicopathologic and molecular features of this unique yet heterogeneous group of diseases are reviewed.

Keywords: Benign fibroosseous lesions; Cementoma; Cementoosseous dysplasia; Fibrous dysplasia; Ossifying fibroma; Osteitis deformans.

Fig. 1

Collagen fiber patterns in normal bone and cementum. (a) Macrolamellar fiber pattern in bone, microlamellar pattern in cementum. (b) Lamellar and woven patterns in osseous trabeculae. (Crossed polars)

Fig. 2

Fibrous Dysplasia. (a) Expansile nonmarginated ground glass opacification in the mandible, (b). Ground glass pattern in the maxilla, (c). Clinical photograph demonstrating cortical expansion, (d). Diffuse unilateral opacification of the maxillary sinus

Fig. 3

Fibrous Dysplasia. Microscopic patterns. (a) Irregular trabeculae with a fibrous element, (b) Polarization microscopy corresponding to figure A shows mature lamellar fiber orientation. (c) Similar fibro-osseous pattern. (d) Polarization microscopy corresponding to figure C depicts a less mature woven fiber pattern

Fig. 4

Osteitis deformans. (a) Osteitis circumscripta of the calvarium, (b). Cotton wool opacification in the maxilla, (c). Mosaic pattern of resting and reversal lines in sclerotic bone regions

Fig. 5

Segmental Odontomaxillary Dysplasia. (a) Replacement of trabeculae by a “sleet storm” configuration and underupted teeth. (b) Fibroosseous microscoscopic pattern with low cellularity, prominent osteocyte hypercellularity and mosaic bone

Fig. 6

Nonexpansile cemento-osseous dysplasias. (a) Periapical Cemental Dysplasia (PACD), a subtype of focal cemento-osseous dysplasia of the anterior mandible begins as a periapical radiolucency. (b) PACD opacifies forming a radiographic “target lesion” in later stages of the disease. (c, d and e). Target lesions in focal cemento-osseous dysplasia affecting the posterior teeth. (c) A traumatic bone cyst is seen at teeth 19 and 20

Fig. 7

Florid Cemento-osseous Dysplasia. (a) Multiple confluent opacities in all four jaw quadrants, (b). Bilateral radiolucent and mixed lucent/opaque lesions, (c). radiolucent regions are empty bone cavities similar to traumatic bone cyst of the jaws

Fig. 8

The Cemento-osseous Dysplasias. (a) Early stage lesion with hemorrhagic foci, (b). Early region with fibro-osseous pattern, (c). Mid stage lesion with progressively more trabeculae, (d). Late stage lesion with sclerotic bone. (e) Late stage lesion with “ginger root” curvilinear confluent trabeculae

Fig. 9

Chronic Sclerosing Osteomyelitis. (a) Diffuse form showing right mandibular opacification, (b). Focal Condensing osteitis with focal opacification at the root apex, (c). Proliferative periostitis showing carious associated tooth and cortical “onion skinning”

Fig. 10

Chronic Sclerosing Osteomyelitis. (a) Fibro-osseous pattern in early stages and around the periphery of solidly opaque regions, (b). Paralleling of trabeculae in proliferative periostitis. (c) Late stage dense osteosclerosis in diffuse sclerosing osteomyelitis

Fig. 11

Hyperparathyroidism. (a) Ground glass diffuse opacification in renal osteodystrophy. (b) Histology is fibro-osseous

Fig. 12

Ossifying fibroma NOS. Radiographically, the lesions are expansile and radiolucent with internal floccular to dense opacities

Fig. 13

Ossifying Fibroma NOS. Microscopic variations. (a) irregular trabeculae with osteoblastic rimming, (b). corresponding to figure A, both lamellar and woven patterns are present, crossed polars, (c). mosaic bone without osteoblastic rimming, (d). corresponding to figure C, predominantly woven bone, crossed polars

Fig. 14

Ossifying Fibroma NOS with trabecular and stromal variations. (a). dystrophic appearing calcifications in a storiform fibrous element, (b). Cementicle calcifications in a patternless stroma, (c). Cemento-ossifying pattern, (d). Whispy calcifications

Fig. 15

Aggressive Juvenile Ossifying Fibroma, Trabecular Type. (a) Expansile maxillary mass, (b). Trabecular bone and hypercellular stroma, (c). ossification poor, hypercellular fibroblastic zones, (d). Focal collections of multinucleated giant cells

Fig. 16

Aggressive Ossifying Fibroma, Psammomatoid Type. (a) Paraorbital well demarcated expansile radioopacity. (b) Psammomatoid calcifications resembling cementicles with a hypercellular stromal element

Fig. 17

Gigantiform Cementoma. (a) Massive mixed radiolucent/radioopaque expansile lesions in both jaws. (b) Fibro-osseous pattern with cementicles and boney trabecuae, the former oftern appearing much larger that those seen in cemento-ossifying fibroma