Juvenile ossifying fibroma. An analysis of eight cases and a comparison with other fibro-osseous lesions

Juvenile ossifying fibroma (JOF) is a well-defined clinical and histologica l entity that has recently been separated from other fibro-osseous lesions, including cemento-ossifying fibromas. Its biological behaviour is well def ined, but unexplained. Its behaviour, clinical and histological appearance, however, bears resemblance to osteofibrous dysplasia of long bones, a lesi on that in some cases has been reported to be part of a spectrum of disease s associated with adamantinoma, thus accounting for its variable biological behaviour. Eight cases of JOF were examined for islands of epithelium or s ingle epithelial cells using immunocytochemistry. While these cases of JOF could clearly be separated from other fibro-osseous lesions, and were histo logically similar to osteofibrous dysplasia, the absence of cytokeratin-pos itive cells in all cases suggests that another reason for its biological be haviour has still to be found.