Unusual causes of carpal tunnel syndrome: space occupying lesions.

Space occupying lesions found at surgery caused or contributed to carpal tunnel syndrome in 23 of 779 patients operated for carpal tunnel syndrome from January 1999 to December 2008. The mean age of these 23 patients was 52.9 years, and in patients who had a local swelling or palpable mass, ultrasonography or magnetic resonance imaging (MRI) was done. All had open release of the transverse carpal ligament and lesions were removed. Histopathology showed tophaceous gout in 10 men, tenosynovitis in seven patients and tumors in eight. The tumors included ganglion cysts in two, lipoma in three and fibroma of the tendon sheath in one. The neurological symptoms subsided after surgery in all. In patients with gout, one had an infected wound and another had recurrence of symptoms 1 year after later. Carpal tunnel syndrome caused by a space occupying lesion is rare and more complicated than idiopathic carpal tunnel syndrome.