ATYPICAL FIBROOSSEOUS LESIONS - DIAGNOSTIC CHALLENGES AND TREATMENT CONCEPTS

The term fibro-osseous lesion is a generic designation of a group of j aw disorders (ranging from inflammatory to neoplastic) that microscopi cally exhibit, a connective-tissue matrix and islands/trabeculae of bo ne. Although the histologic appearance, and frequently the clinical an d radiographic features, may be similar for many of these lesions, the y demonstrate a wide range of biologic behavior. Treatment therefore i s varied, and there are few well-established guidelines to help the su rgeon. Five fibro-osseous lesions with atypical features are presented to demonstrate the diagnostic difficulties associated with these lesi ons and to show the need for accurate classification in order to help direct treatment and predict outcome. Final diagnoses for ''atypical'' fibro-osseous lesions included: multiple ossifying fibromas, unclassi fiable fibro-osseous lesion, osteosarcoma with concomitant multiple os sifying fibromas, juvenile or psammomatoid ossifying fibroma, and cent ral low-grade osteosarcoma. ''Fibro-osseous lesion'' should be viewed as a working diagnosis, and a definitive diagnosis should be actively sought; the addition of ''atypical'' to this designation suggests the likelihood of an aggressive lesion. Treatment of lesions having atypic al and nonclassical microscopic features must be based on the biologic behavior of the tumor.