Endoscopic findings and clinicopathologic characteristics of colonic schistosomiasis: a report of 46 cases.

AIM: To make a retrospective analysis of endoscopy findings and clinicopathologic characteristics of colonic schistosomiasis in order to further improve our understanding of the disease and decrease its misdiagnosis.
METHODS: Endoscopy findings and clinicopathologic characteristics of 46 intestinal schistosomiasis patients were retrospectively analyzed. All the patients underwent colonoscopy and all biopsy specimens stained with hematoxylin and eosin were observed under a light microscope.
RESULTS: Of the 46 colonic schistosomiasis patients, 1 was diagnosed as acute schistosomal colitis, 16 as chronic schistosomal colitis and 29 as chronic active schistosomal colitis according to their endoscopic findings and pathology. Not all patients were suspected of or diagnosed as colonic schistosomiasis. Of the 12 misdiagnosed patients, 4 were misdiagnosed as ulcerative colitis, 1 as Crohn's disease, and 7 as ischemic colitis. The segments of rectum and sigmoid colon were involved in 29 patients (63.0%). Intact Schistosoma ova were deposited in colonic mucosa accompanying infiltration of eosinocytes, lymphocytes, and plasma cells in acute schistosomal colitis patients. Submucosal fibrosis was found in chronic schistosomal colitis patients. Among the 17 patients with a signal polyp, hyperplastic polyp, canalicular adenoma with a low-grade intraepithelial neoplastic change, tubulovillous adenoma with a high-grade intraepithelial neoplastic change were observed in 10, 5, and 2 patients, respectively. Eight out of the 46 patients were diagnosed as colonic carcinoma.
CONCLUSION: Endoscopy contributes to the diagnosis of colonic schistosomiasis although it is nonspecific. A correct diagnosis of colonic schistosomiasis can be established by endoscopy in combination with its clinicopathologic characteristics.