An Unusual Case of Tuberculosis Infection of the Hand with Peritonitis.

Tuberculosis (TB), primarily a pulmonary disease, manifests extrapulmonary involvement in 20% of cases, though concurrent infections in distant sites like the hand and abdomen are exceedingly rare. This report presents an exceptionally rare case of concurrent tuberculosis osteomyelitis of the hand and peritoneal tuberculosis in a 19-year-old male-an unusual dual presentation not commonly documented in the literature. The patient had an 8-month history of progressive right little finger swelling, initially misdiagnosed as an enchondroma, and subsequently developed acute abdominal pain and ascites, with computed tomography (CT) revealing diffuse peritoneal thickening and peritonitis. Ascitic analysis showed exudative fluid with elevated CA-125, and an interferon-gamma release assay (IGRA) was positive, prompting TB suspicion. Histopathology of debrided hand tissue revealed granulomatous inflammation with necrosis, and Mycobacterium tuberculosis was confirmed by acid-fast staining and fluorescence in situ hybridization (FISH). Treatment combined surgical debridement, bone grafting, and vacuum-assisted drainage for the hand lesion with a 12-month HRZE regimen. Abdominal TB resolved with medical therapy alone. The patient achieved complete recovery with restored finger function and no recurrence over 2 years. This case underscores TB's protean manifestations, emphasizing diagnostic challenges in paucibacillary disease and the utility of IGRA and molecular confirmation (FISH). Clinicians should maintain high suspicion for TB in atypical osteolytic lesions or idiopathic serositis, particularly in endemic regions, to ensure timely multidisciplinary management.