Unusual cause of the thumb basal joint pain: osteoid osteoma of the trapezium.

The trapezium is rare site of osteoid osteoma development. The diagnostic challenge lies in its rare occurrence, and requires differentiation from various disease entities causing thumb basal joint pain. We report the case of a 29-year-old male who presented with severe thumb basal joint pain. He was initially treated for calcific periarthritis because of concomitant calcifications around the thumb basal joint, but had undiscovered osteoid osteoma. A high index of suspicion to a patient with wrist pain unresponsive to prior treatment is necessary for diagnosis of osteoid osteoma.