A case report of synchronous osteoblastoma and fibromatosis.

Osteoblastoma is a rare bone tumour that accounts for 1% of all primary bone tumours and 3% of all benign bone tumours. Osteoblastoma occurring in long bones has a predilection for the meta-diaphysis. It bears a close histological resemblance to osteoid osteoma, but it is not growth limited - usually 2 cm or greater at diagnosis. The term "fibromatosis" covers a broad spectrum of benign fibrous tissue proliferations. It is characterized by infiltrative growth and a tendency for recurrence; however, unlike sarcoma, it never metastasizes. To our knowledge, this is the first case report in the English literature of a patient with synchronous presentation of an osteoblastoma and fibromatosis.