Mycobacterium fortuitum granulomatous synovitis caused by a dog bite

Mycobacterium fortuitum was isolated from the synovial tissues of the dorsum of the hand after a dog bite. Caseating granulomas with Langhans' type giant cells were demonstrated microscopically. Healing followed prolonged treatment with antituberculosis drugs. It is suggested that the organism was forced into the patient's tissues by the dog's bite.