S5102 Omental Tuberculosis: The Great Imitator in the Abdomen

Introduction: Tuberculosis (TB) cases, while rare in the United States, have been on the rise over the past few years. Most commonly, it affects the lungs. Early diagnosis is crucial to successful treatment and decreased spread of tuberculosis. In this case, we present a patient who initially presented with abdominal pain and was found to have an atypical presentation of extrapulmonary TB in the omentum. Case Description/Methods: A 71-year-old woman of Eastern Asian descent with a past medical history of rheumatoid arthritis presented to the emergency department with abdominal pain and fevers. On admission, she had intermittent fevers, but blood and urine cultures were negative. Imaging revealed significant ascites, omental thickening, and peritoneal enhancement, highly suggestive of peritoneal carcinomatosis. Omental biopsy results showed fibroadipose tissue with necrotizing granulomatous inflammation and no malignant cells. Notably, she had a positive QuantiFERON gold test 2 weeks prior, but was diagnosed with latent tuberculosis (TB) due to lack of respiratory symptoms. Although fungal and acid-fast testing of the peritoneal fluid was unremarkable, omental TB was the ultimate diagnosis due to biopsy results and the recently positive QuantiFERON gold test. Infectious disease (ID) was consulted and started rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) therapy with a plan for close ID follow-up on discharge to ensure appropriate treatment of her infection. Discussion: While TB in the United States is uncommon, certain high-risk groups require heightened suspicion. This includes incarcerated and homeless individuals, lower socioeconomic status, healthcare workers, travelers to endemic areas, and immunocompromised patients. Active TB is usually pulmonary, presenting with fever, night sweats, hemoptysis, weight loss, and cavitary lung lesions on imaging. Extrapulmonary TB is most commonly found in the lymph nodes, but can also spread to the pleura, bone, central nervous system, omentum, or genitourinary system. While rare, it is important to consider extrapulmonary TB in the differential for patients presenting with vague GI symptoms who are among these high-risk groups.