Differential diagnosis of fibro-osseous jaw lesions. A histological investigation on 30 cases.

A series of 30 fibro-osseous jaw lesions was evaluated for histological parameters that enable appropriate diagnostic classification. Special emphasis was laid upon the histomorphology of the lesion-jawbone interface, blending of lesional bone with adjacent jawbone being employed as the decisive factor in distinguishing between fibrous dysplasia and other fibro-osseous jaw lesions. Using this feature as a discriminative tool, other histological aspects that were useful in differential diagnosis could be identified. Fibrous dysplasia (n = 11) shows a rather uniform appearance with a constant ratio bone: fibrous tissue throughout the entire lesion; acellular mineralized particles are virtually absent. Juvenile ossifying fibroma (n = 3) is characterized by a highly cellular fibroblastic stroma and garland-like strands of cellular osteoid. Ossifying fibroma (n = 12) shows a high variability in stromal cellularity and types of mineralized material. Localized periapical fibro-osseous cemental lesions (n = 4) are histologically almost similar to ossifying fibroma although more heavily mineralized. It is concluded that there is full agreement between histology and radiology in indicating whether a fibro-osseous jaw lesion is demarcated or blends into its surroundings. Moreover, an appropriate diagnosis can be reliably made on histological grounds.