Synovial Hemangioma of the Wrist With Cystic Invasion of Trapezoid and Capitate Bones.

Synovial hemangiomas (SHs) are rare lesions of the joints or tendon sheaths that are difficult to diagnose. We present the case of an 18-year-old man with an SH in the wrist joint. Physical examination revealed a slightly tender, ill-defined, nonpulsatile soft mass, 3 cm × 3 cm in size on the dorsal aspect of the left wrist. Computed tomography showed an irregular, ill-defined, soft tissue mass in the expanded joint space, which was formed by the scaphoid, trapezoid, and capitate bones. Magnetic resonance imaging showed the typical features of SH and also revealed cavitary erosion of the scaphoid, trapezoid, and capitate bones. An open arthrotomy was performed via a dorsal approach, and the mass was excised. The histological examination findings were consistent with the diagnosis of SH.