S5460 Isolated Hepatic Tuberculosis Mimicking Metastatic Liver Lesions in a 68-Year-Old Woman

Introduction: Isolated hepatic tuberculosis (TB) is a rare form of extrapulmonary TB that occurs without pulmonary or miliary involvement, accounting for less than 1% of TB cases. It can radiographically mimic liver metastases or primary malignancies, posing a significant diagnostic challenge and risk of misdiagnosis. Case Description/Methods: A 68-year-old woman presented with several weeks of low-grade fever, weight loss, and dull right upper quadrant abdominal pain. She denied alcohol use or known TB exposure. Physical examination revealed mild hepatomegaly without jaundice or ascites. Labs showed elevated alkaline phosphatase (460 U/L) with normal bilirubin and transaminases. Autoimmune serologies were negative. Viral hepatitis panel and tumor markers (alpha-fetoprotein, CA 19-9, CEA) were unremarkable. Contrast-enhanced computed tomography revealed multiple well-circumscribed hypodense lesions in both liver lobes with peripheral rim enhancement, raising concern for metastatic disease. No lymphadenopathy or extrahepatic masses were seen. Extensive malignancy workup including endoscopy, mammography, and positron emission tomography-computed tomography was negative. On hospital day 5, ultrasound-guided liver biopsy was performed. Histopathology showed necrotizing granulomas with Langhans-type giant cells, and Ziehl–Neelsen staining demonstrated acid-fast bacilli. TB polymerase chain reaction (PCR) confirmed Mycobacterium tuberculosis. Chest X-ray revealed no pulmonary involvement. The patient was started on standard RIPE therapy. By 2 months, she experienced resolution of systemic symptoms, and repeat imaging showed marked regression of hepatic lesions. Discussion: Hepatic TB can mimic metastatic cancer on imaging due to its nonspecific radiologic appearance, often presenting as hypodense or rim-enhancing lesions. These features can lead to unnecessary surgical interventions or delays in appropriate treatment. Diagnosis requires histopathology showing caseating granulomas, with AFB staining or TB PCR to confirm. The prognosis is excellent with anti-tuberculous therapy. Clinicians should maintain high suspicion for hepatic TB in patients with liver lesions from endemic areas or unclear systemic symptoms. This case highlights the importance of biopsy in distinguishing rare infectious mimics of hepatic malignancy.