Adamantinoma is known as a low-grade malignant biphasic
tumor. Classic
adamantinoma is in general characterized by admixture of both epithelial and osteofibrous components that are associated with various proportions and differentiation patterns.
Osteofibrous dysplasia (OFD) is a self-limited benign fibro-osseous lesion of bone during infancy and childhood. OFD-like
adamantinoma is characterized by predominance of osteofibrous tissues, in which small groups of epithelial cells are only detected by careful search or immunohistochemistry. There have been controversies as to the potential correlation among OFD, OFD-like
adamantinoma and classic
adamantinoma. We report an unusual case of
adamantinoma arising in the tibia, with an extensive review of the literature. The present findings suggest a direct correlation between OFD-like
adamantinoma and classic
adamantinoma. At the age of 12 years, the tibial biopsy lesion was diagnosed as OFD. At the age of 23, the lesion became larger and more destructive on
x-ray films. The biopsy lesion was diagnosed as classic
adamantinoma. Wide excision was performed. The primary lesion was retrospectively diagnosed as OFD-like
adamantinoma because of presence of
keratin-positive epithelial cells within the stroma. At five years after surgery, the patient was free from recurrence or
metastasis. The retrospective histological findings of OFD-like
adamantinoma in the original biopsy and of a classic
adamantinoma in all sections of the later resection specimen raised the possibility of an unusual progression of OFD-like
adamantinoma to a classic
adamantinoma. The present case and the literature review suggest that an OFD-like
adamantinoma may be a precursor lesion of classic
adamantinoma. Therefore, the possibility of progression of OFD-like
adamantinoma to a classic
adamantinoma should be kept in mind, particularly when the destructive changes are seen radiologically.