S4090 Gastric Adenocarcinoma Presenting With Features Mimicking Abdominal Tuberculosis: A Diagnostic Challenge

Introduction: Differentiating between peritoneal tuberculosis (TB) and carcinomatosis remains challenging due to overlapping presentations. This diagnostic dilemma affects clinical management, particularly in patients with rapid clinical deterioration. Features including young age, exudative ascites, normal tumor markers, and characteristic “frozen abdomen” appearance can occur in both conditions, necessitating careful evaluation. Case Description/Methods: A 36-year-old man with peptic ulcer disease presented with abdominal pain and 80-pound weight loss over 2 months. Computed tomography showed peritoneal disease with complex ascites. Tumor markers were normal. Upper endoscopy revealed a 4 cm gastric antral lesion, but initial biopsies showed only hyperplastic changes. Paracentesis yielded exudative ascites with negative cytology. The patient deteriorated within 2 weeks, developing bowel perforation. Laparoscopy revealed a “frozen abdomen” with dense adhesions. QuantiFERON-TB Gold returned indeterminate. The patient developed septic shock requiring Intensive Care Unit care. Re-examination of initial biopsies eventually confirmed gastric adenocarcinoma. Discussion: This case illustrates key diagnostic challenges: (1) normal tumor markers don't exclude peritoneal carcinomatosis; (2) initial negative biopsies occur in both TB and malignancy; (3) the “frozen abdomen” appearance isn't specific to either condition; (4) delayed diagnosis can lead to devastating outcomes. Research shows peritoneal TB typically affects younger patients (mean 39.2 years vs 60 years in carcinomatosis) and presents with more frequent abdominal masses (40.0% vs 10.5%), while abdominal distension is more common in carcinomatosis (78.9% vs 53.3%).