[Osteoid osteoma: about a case].

Osteoid osteoma is a benign primary bone tumor. This tumor is relatively frequent, accounting for 12% of all benign bone tumors and about 2-3% of all bone tumors. We report a new case of osteoid osteoma confirmed histologically. A 30-year old patient was referred for evaluation of chronic ankle pain. Front and lateral radiographs of the ankle showed a heterogeneous lesion located in the neck of the talus without soft tissue abnormalities. The CT scan of the ankle showed a nodular, hypodense lesion located in the neck of the talus with a limited osteosclerotic reaction.