Flexor carpi radialis tendon tear due to scaphoid osteoid osteoma: A case report.

Osteoid osteoma is a benign osteoblastic tumor with a low incidence. Due to its uncommon and often confusing clinical presentation, accurate diagnosis is frequently significantly delayed. We report a case of a 56-year old right-handed woman with a history of increasing pain in her right scaphotrapeziotrapezoidal (STT) joint and distal flexor carpi radialis (FCR). Due to its confusing clinical presentation, the diagnosis of a parosteal osteoid osteoma in the scaphoid and a rupture of the FCR, presenting as a Mannerfelt like lesion, was delayed for 1 year. The patient was treated with surgical exploration and excision. At follow-up, the patient recovered with complete resolution of pain and resumed daily life activities after 2 weeks. A high index of suspicion remains the key point in the diagnosis of osteoid osteoma, certainly in cases of unusual clinical presentation and anatomic localization as presented in this case.