Schistosomiasis is a snail-transmitted trematodiasis acquired by immersion in water which contains the cercariae. In Korea, six imported cases of urinary schistosomiasis by Schistosoma haematobium and one case of imported cerebral schistosomiasis by S. mansoni were reported. Herein we report a case of S. mansoni infecting rectum of a 46 year-old Korean male, who had been to Saudi Arabia for two years. On colonoscopy for routine physical check up, a 0.4 cm polyp in the rectum was detected and biopsy was done. Microscopically, rectal mucosa showed several granulomas which were composed of macrophages, lymphocytes, neutrophils and eosinophils. The center of each granuloma showed an ovoid egg often containing miracidium. The eggs measured 130 x 60 microns in average size. They had yellowish-brown transparent shell with the characteristic lateral spine. This is the 8th imported case of schistosomiasis in Korea and the second one infected by S. mansoni.
