Case Report: Probable hepatosplenic tuberculosis mimicking undifferentiated connective tissue disease and malignancy

Background Hepatosplenic tuberculosis is a rare form of extrapulmonary tuberculosis with nonspecific manifestations, often leading to misdiagnosis. Tuberculosis can mimic connective tissue disease by presenting with systemic symptoms and positive autoantibodies, posing a diagnostic challenge. Case presentation We report a 69-year-old woman with polyarthralgia, oral ulcers, and positive autoantibodies including antinuclear antibody (ANA), anti-keratin antibody (AKA), and antiphospholipid antibodies, who was initially diagnosed with undifferentiated connective tissue disease (UCTD). Despite hydroxychloroquine treatment, she developed fever, weight loss, and neuropathy. Positron emission tomography-computed tomography (PET-CT) revealed multiple hypermetabolic hepatic and splenic lesions and abdominal lymphadenopathy, suspicious for malignancy. Liver biopsy demonstrated necrotizing epithelioid granulomas, which were highly suggestive of tuberculosis. In the context of a positive interferon- γ release assay, compatible imaging, consideration of relevant alternatives, and subsequent treatment response, probable hepatosplenic tuberculosis was considered the most likely diagnosis. Anti-tuberculosis therapy led to significant clinical and radiological improvement as assessed at six weeks. Conclusions Our case highlights that probable hepatosplenic tuberculosis can mimic autoimmune diseases and malignancies. Biopsy is key to diagnosis, and treatment response may be supportive even when microbiology is negative.