Anti‐synthetase syndrome complicated by multifocal tuberculosis: A thought‐provoking differential diagnosis with tumors

Abstract Mycobacterium tuberculosis , which mainly affects the lungs but can also invade other systems, presents a diagnostic challenge when co‐existing with autoimmune disease. We report a case of 31‐year‐old Asian woman with anti‐synthetase syndrome who developed abdominal and subcutaneous lumps during treatment, along with elevated tumor markers, raising suspicion of malignancy. Pathological examination revealed M . tuberculosis infection, changing the diagnosis to multifocal extrapulmonary tuberculosis. This case highlights the need for prompt and detailed evaluations, and the importance of broad differential diagnosis.