We report the case of an 80-year-old woman who presented with an asymptomatic slowly growing mass in the dorsal aspect of her right wrist. Radiographs revealed a snail-shaped radiopaque structure. Surgical exploration and excision revealed a calcified lesion over the extensor digitorum communis. Histopathological analysis confirmed the diagnosis of tenosynovial chondromatosis. At the last follow-up, four years after surgery, the patient was asymptomatic and free of recurrence. Practitioners and hand surgeons should be aware of the dorsal involvement and evocative radiological calcifications of tenosynovial chondromatosis, which is a rare benign soft tissue neoplasm that affects all tendon sheaths of the hand.