Hepatobiliary Nontuberculous Mycobacterial Infection Mimicking Malignancy in a Patient with Anti-Interferon-γ Autoantibodies.

Obstructive jaundice is a common digestive disorder with multiple etiologies. Non-tuberculous mycobacterial (NTM) infection is an opportunistic disease that may present with localized pulmonary involvement or disseminated multi-organ manifestations. However, biliary involvement in disseminated NTM infection is rare, and its characteristics and progression remain poorly understood. We report a patient with progressive jaundice who was eventually considered to have probable biliary NTM infection after comprehensive evaluation, exclusion of alternative etiologies, and a favorable therapeutic response despite negative microbiological testing. Endoscopic retrograde cholangiopancreatography (ERCP) was performed to relieve biliary obstruction, but the patient developed recurrent and refractory ampullary bleeding requiring repeated endoscopic interventions. Clinical improvement was achieved following combined antimycobacterial therapy and immunomodulatory treatment. Biliary NTM infection is a rare cause of obstructive jaundice, and ERCP remains necessary for biliary decompression, while post-ERCP bleeding risk should be carefully monitored.