To identify the features differentiating peritoneal tuberculosis from carcinomatosis on CT scan abdomen taking omental biopsy as a gold standard.

OBJECTIVE: To differentiate peritoneal tuberculosis from carcinomatosis on computed tomography scan of abdomen, taking omental biopsy as the gold standard..

METHODS: This retrospective diagnostic accuracy review of cases was conducted at Aga Khan University Hospital, Karachi, and comprised patient's medical record files from February 2007 to February 2016. Computed tomography scan findings were compared with diagnosis made on the basis of histopathology. Multiple logistics regression analysis was done and sensitivity and specificity were tested through Pearson chi square test.

RESULTS: Of the 98 patients identified, 62(63.2%)were found to be cases of disseminated tuberculosis and 36(36.7%) were diagnosed as malignant on histopathology. Computed tomography features were significantly specific to differentiate abdominal tuberculosis from carcinomatosis (p=0.004). On computed tomography,4 findings showed statistical significance: Smooth thickening of the peritoneum (p<0.001), abdominal mass (p=0.03), lymph node necrosis (p=0.024) and high-density ascitic fluid (p<0.001). Out of these, smooth thickening of the peritoneum (sensitivity=77%; specificity=86.1%) and high-density ascitic fluid (sensitivity=68.9%; specificity=72.2%) were more specific findings. Overall, the sensitivity and specificity of computed tomography was found to be 88.5% and 83.3%, respectively.

CONCLUSIONS: Although no single finding on a computed tomography scan was diagnostic proof of peritoneal tuberculosis, a combination of findings could reliably distinguish between peritoneal tuberculosis and carcinomatosis. .