Periosteal osteoblastoma of the pelvis: a rare case.

Among the rare bone tumors, the osteoblastoma is a fascinating tumor. The rarity, the predisposition to occur in any bone and the diagnostic dilemma makes this infrequent tumor interesting. It is sporadically reported in the literature and what is rarer is its occurrence in the pelvis. The unusual location and inconclusive radiographic findings with diffused diagnostic evidences delays the management of benign osteoblastoma. We encountered a patient with benign osteoblastoma of the pubic ramus of right side. An excisional biopsy was performed. Peroperatively, the tumor appeared as oval, reddish brown, bony hard mass lying just over the cortex of the right pubic ramus and not breaching the cortex. Histopathological study revealed an osteoid rich lesion. Its presence in pubis must not be ignored and periosteal osteoblastoma should be considered as a differential diagnosis.