Schistosomal colonic polyposis and ulcerative colitis with variable thickening of the subepithelial collagen layer: a possible resemblance to collagenous colitis

ABSTRACT

The clinical and histopathological features of schistosomal colonic polyposis and ulcerative colitis were studied in 32 and 7 patients, respectively. Schistosomal patients presented with bleeding per rectum in 100% of dysentery in 75%, liver enlargement in 100%, splenic enlargement in 80%, schistosomal mass in 42% and nail clubbing in 31%. While ulcerative colitis patients presented with abdominal cramp in 71% and recurrent bleeding per rectum in all of the cases. Sigmoidoscopy and barium enema detected schistosomal colonic polyposis in the rectum in 31% of cases, rectosigmoid in 43% and in descending colon in 20% of patients. The same procedures done for ulcerative colitis patients showed mucosal changes and superficial ulceration in all cases; loss of haustrations in 70% of patients. From the histopathological point of view, schistosomiasis simulated collagenous colitis in many of its features as increase in the mean thickness of subepithelial collagen layer, absence of generalized crypt damage, mild lymphocytic infiltration of crypt epithelium and the presence of some autoimmune manifestations in schistosomiasis. Cases showing no schistosomal egg in the stools showed on electron microscopy remnants of schistosomal egg shells and shreds of teguments inside the lysosomes of macrophages lying in the lamina propria. Thus, electron microscopy served as an augmented diagnostic tool