Subungual glomus tumor diagnosis based on imaging.

A 50-year-old woman had had tenderness of the nail bed of the right thumb for more than 20 years. For the previous 5 or 6 years, she had also had attacks of pain with exposure to cold, and deformity of the right thumb nail plate began to appear. There was red discoloration on the proximal aspect of the nail bed, and a longitudinal fissure on the distal aspect of the nail plate. Ultrasonography showed a well-circumscribed hypoechoic area under the proximal aspect of the nail plate and the nail matrix. Color Doppler ultrasonography showed subtle flow signals within the hypoechoic area. Magnetic resonance imaging showed a well-circumscribed mass in the same place that the ultrasonography indicated. It was isointense to the dermis of the nail bed on the T1-weighted image and hyperintense on the T2-weighted image. Radiography showed subtle dorsal bone erosion in the distal phalanx. Surgery was performed. Histologically, the diagnosis of a subungual glomus tumor was made. We diagnosed the exact location and size of the subungual glomus tumor by preoperative imaging and completely removed it easily and safely. Imaging is very useful for diagnosing tumors of the nail unit.