Flexor tenosynovitis in the hand caused by Mycobacterium terrae

The authors describe an uncommon case of flexor tenosynovitis caused by Mycobacterium terrae, an atypical mycobacterium generally considered nonpathogenic in humans. A prolonged delay in diagnosis and various ineffective therapies led to synovial biopsy and culture. After confirming the diagnosis of M. terrae, appropriate antimycobacterial chemotherapy resolved the synovitis. For chronic tenosynovitis without a clear etiology, limited synovectomy and culture are essential in establishing a diagnosis and in initiating treatment for this atypical mycobacterial infection.