Journal of the Medical Association of Thailand Vol 95, No 11:NOVEMBER 2012 0125-2208 95 11 2012 Nov Abdominal CT Findings to Distinguish between Tuberculous Peritonitis and Peritoneal Carcinomatosis 1449 EN Aphinya Charoensak Pavinee Nantavithya Piyaporn Apisarnthanarak Original Article  Determine useful CT findings for differentiation between tuberculous peritonitis and peritoneal carcinomatosis. Abdominal CT scans in 27 clinically or pathologically proven cases of tuberculous peritonitis and 53 pathologically proven cases of peritoneal carcinomatosis were retrospectively reviewed. CT findings were assessed for ascites, abnormalities of peritoneum, omentum, and mesentery, abdominal lymphadenopathy, and other associated findings in abdomen, bone, and lung bases. Statistical differences of CT findings between two diseases were analyzed using Chi-square or Fisher’s exact test. Fibrin in ascites was found in 5/26 patients with tuberculous peritonitis but none in peritoneal carcinomatosis (p < 0.05). Smooth and uniform peritoneal thickening was more frequently seen in tuberculous peritonitis (p < 0.001), but irregular peritoneal thickening and peritoneal nodules were more frequently seen in peritoneal carcinomatosis (p < 0.001). Type of omental abnormalities showed significantly differed between two diseases (p < 0.001). Smudge type was more commonly found in tuberculous peritonitis, while nodular and cake types were more commonly detected in peritoneal carcinomatosis. Lymph nodes size < 1 cm and location of lymph nodes at peripancreatic region were more frequently identified in tuberculous peritonitis, whereas lymph nodes size ≥ 1 cm and contour abnormality of the liver or the spleen were more frequently visualized in peritoneal carcinomatosis (p < 0.05). Although some CT findings were overlapped, the present study addressed some useful CT findings for differentiation between tuberculous peritonitis and peritoneal carcinomatosis. Computed tomography Tuberculosis Peritonitis Peritoneal carcinomatosis