A clinicopathological and immunohistochemical study of osteofibrous dysplasia, differentiated adamantinoma, and adamantinoma of long bones.

A clinicopathological and immunohistochemical study of 12 cases of osteofibrous dysplasia (OFD), two cases of differentiated adamantinoma, and five cases of adamantinoma of long bones is presented. Although OFD and differentiated adamantinoma showed similar radiologic findings, differentiated adamantinoma was more likely to be a recurrent lesion than osteofibrous dysplasia and seemed to require a more extensive surgical procedure. Immunohistochemically, cytokeratin- and vimentin-positive cells were seen in both OFD and differentiated adamantinoma. The positive cells were scattered in the former, and were both scattered and nest-like in the latter. Both these lesions, however, were negative for epithelial membrane antigen. Excluding two cases of Ewing-like adamantinoma, the other three cases of adamantinoma were also positive for cytokeratin and vimentin. These results suggest that these three lesions share the same histogenetic origin. The two cases of Ewing-like adamantinoma differ from tibial adamantinoma in their radiological, histological and immunohistochemical aspects, and seem to constitute a distinct variant of adamantinoma with a different histogenesis.