Tenosynovitis caused by Mycobacterium kansasii associated with a dog bite

A 68-year-old man with adult-onset diabetes mellitus suffered an accidental puncture wound to the palm of his hand while playing with his pet dog. He received cephalosporin prophylaxis for 1 week. No inflammation occurred. Six months later, a mass developed near his elbow. It was removed. Histopathology revealed granulomas containing acid-fast bacilli (AFB). No culture was done. Swelling and decreased motion of the wrist and fingers developed. Magnetic resonance imaging revealed inflammation of the flexor compartment of the hand, wrist, and forearm. Surgical incision and drainage yielded purulent material, granulomatous inflammation, with AFB. Cultures yielded Mycobacterium kansasii. Several surgical procedures were required; M kansasii was recovered. He received isoniazid and rifampin for 1 year and prolonged rehabilitation. After 4 years, he was relatively asymptomatic, with good function of wrist and fingers. We believe this to be the first report of tenosynovitis caused by M kansasii in association with a dog bite.