Mycobacterium malmoense infection. An unusual cause of wrist swelling.

We report a case of non-tuberculous tenosynovitis of the wrist caused by Mycobacterium malmoense. The patient presented with a ganglion-like swelling on the flexor aspect of the wrist. The diagnosis was confirmed by fine needle aspiration biopsy. A satisfactory resolution was obtained by antibiotic therapy alone, indicating that radical synovectomy may not be necessary in all cases of M. malmoense infection.