Osteomyelitis and septic arthritis due to Mycobacterium marinum

65-year-old woman with history of puncture wound of distal phalanx from contact with fish spines who presented with swelling and pain at site of minor injury. Mycobacterium marinum was recovered from synovial biopsy. Frontal radiograph of digit shows soft-tissue swelling (arrowheads), marginal osseous erosion at corner of distal interphalangeal joint (curved arrow), and remarkable joint-space narrowing (straight arrows), consistent with septic arthritis and osteomyelitis.