Mycobacterium abscessus Hand Infection Mimicking Dactylitis Due to Spondyloarthritis: A Case Report.

Mycobacterium abscessus is an environmental, rapid-growing non-tuberculosis Mycobacterium commonly found in soil and water. While typically causing pulmonary infections, it can present with musculoskeletal manifestations that mimic inflammatory arthritis. We present a case of a 73-year-old woman who developed progressive hand tenosynovitis following a gardening injury. The clinical presentation initially suggested seronegative spondyloarthritis, particularly due to the presence of dactylitis. However, synovial biopsy and culture ultimately revealed M. abscessus subsp. abscessus infection. This case highlights the importance of considering atypical infections in the differential diagnosis of apparent inflammatory arthritis, especially with unilateral involvement and inadequate response to conventional therapy.