Peritoneal Tuberculosis Presenting as Omental Caking and Carcinomatosis: A Case Report

Abstract Peritoneal tuberculosis is the sixth leading cause of extrapulmonary tuberculosis in North America. It constitutes a challenging diagnosis due to its nonspecific presentation and findings that can be mistaken for malignancy. This report details a case where findings initially suggested malignancy but were ultimately attributed to peritoneal tuberculosis.Case Presentation: A 27-year-old female with a history of recurrent urinary tract infections (UTIs) presented to the emergency department with fatigue, malaise, abdominal distention, and dysuria. She was admitted for suspected sepsis from UTI. A computed tomography (CT) scan revealed moderate ascites, hilar, and mediastinal lymphadenopathy. Diagnostic paracentesis yielded ascitic fluid with a predominantly lymphocytic cell count, negative cytology, and significantly elevated adenosine deaminase. Serum studies showed elevated tumor marker CA-125. Transvaginal ultrasound (TVUS) and pelvic ultrasound were unremarkable. Given the high suspicion of malignancy, MRI of the pelvis with contrast revealed multiseptated ascites with diffuse peritoneal enhancement and multiple foci of enhancing nodularity along the peritoneum. Further investigation included a positive serum QuantiFERON test, raising suspicion of infectious etiology. Due to an ambiguous diagnosis, the patient underwent a laparoscopic peritoneal biopsy. Intraoperative findings included multiple miliary nodules across the peritoneum and omentum. Biopsy reported necrotizing granulomatous inflammation without malignant cells. The patient denied travel outside the US; however, she admitted to living and working in an immigrant-rich community in Texas. This epidemiological context and biopsy findings supported the diagnosis of peritoneal tuberculosis. The patient was initiated on a standard RIPE (rifampin, isoniazid, pyrazinamide, and ethambutol) regimen for two months, followed by isoniazid and rifampin. At four-month follow-up, the symptoms had resolved; repeat CT imaging showed a reduction in lymphadenopathy, marked improvement in peritoneal nodularity, and resolution of ascites.Discussion: This case highlights diagnostic complexities associated with peritoneal tuberculosis. The non-specific nature of symptoms and imaging findings often lead to a delay in diagnosis. The gold standard remains a biopsy of peritoneal tissue. Prompt initiation of RIPE therapy is crucial for improving patient outcomes. Conclusion: Gastrointestinal tuberculosis accounts for only 1-3% of worldwide tuberculosis cases. It can present as part of an active pulmonary disease or as a primary infection without pulmonary involvement. When the peritoneum is the primary infection, the presenting signs and symptoms closely resemble malignancy. Clinicians should consider peritoneal tuberculosis in differential diagnoses, especially in patients from high-risk communities. Timely biopsy and appropriate antimicrobial therapy are critical for accurate diagnosis and effective management.