A 47-year-old right-handed housewife noted a soft swelling on the volar aspect of her left distal forearm 3 years ago. She was diagnosed with a ganglion, and local resection surgery was performed twice at another hospital. Similar methods were used to perform both operations, which involved intralesional resections of the cyst with 1-cm skin incisions of the volar aspect of the forearm without following the stalk of the cyst. However, 1 year after the last surgery, the swelling reappeared and was associated with numbness and pain in the radial volar aspect of the hand, thumb, index finger, and middle finger. She came to our hospital and a physical examination revealed decreased sensitivity of the left median nerve area associated with a positive Tinel's sign on the volar aspect of the distal forearm. The patient had no evidence of polyneuropathy, vasculitis, tuberculosis, hypertrophic tenosynovitis, sarcoidosis, gout, or other systemic disorders. She did not give history of previous trauma except for the surgeries at the other hospital, and her wrist joint showed no signs of carpometacarpal arthrosis or instability. The nerve conduction velocity (44.2 m/s) and terminal latency (5.94 ms) of the left median nerve were prolonged and delayed respectively, compared with those of the contralateral nerve (58.0 m/s, 4.12 ms). A radiograph of her left forearm showed no space-occupying lesions around the median nerve and carpal tunnel, and significant osteoarthritic changes of the carpal bones were not observed. Magnetic resonance imaging revealed that the multi-cystic lesion originated from the Scaphotrapezial joint and had expanded beyond the wrist (Figure 1).
We decided to perform surgery. Exploration of the left median nerve showed that it was compressed by a large ovoid cystic lesion at the distal forearm near the proximal end of the carpal tunnel (Figure 2). We resected the cystic lesion, following the stalk of the cyst to the Scaphotrapezial joint with elongation of the incision, and released the carpal tunnel simultaneously. Nerve compression was observed only around the cyst in the distal forearm and not in the carpal tunnel. Her symptoms had disappeared 1 week after surgery, and pathological examination of the resected cystic lesion showed an appearance consistent with a ganglion. On the basis of these findings, we diagnosed median nerve neuropathy in the forearm due to recurrence of anterior wrist ganglion originated from the Scaphotrapezial joint. Complications or recurrent symptoms were absent 13 months after surgery.