| Abstract: | Abstract: The authors investigated clinical data and pathological findings of eight cases of IIa+IIc type early colorectal cancer which showed minimal invasion in the mucosal laver, but massive invasion in the submucosal layer (deep invasion type). The average age of these 8 patients was 57.8 years (6 out of 8 cases were between 55 and 61-years-old). 6 patients were males; 2 were females. Five patients were asymptomatic with a positive reaction for fecal occult blood; the other 2 had anal bleeding. All but 1 patient were diagnosed as having the IIa+IIc type of cancerous lesion, by barium enema examination and colonoscopy. Five patients had lesions in the sigmoid colon, 2 had lesions in the rectum, and 1 had a lesion in the ascending colon. The maximum lesion diameters ranged from 5 to 25 mm, averaging 15.9 mm. Six lesions were less than 20 mm in maximum diameter; 3 of these were less than 10 mm. Pathologically, 5 cases were moderately differentiated adenocarcinoma, 2 were well differentiated adenocarcinoma, and one was poorly differentiated adenocarcinoma. None of the lesions had a coexisting adenomatous component. The incidence of lymph node metastasis was considerably higher than expected (2 out of 8 cases) for early invasive colorectal cancer. Our results suggest that the deep invasion type of early colorectal cancers (which probably arise de novo) are, though small as a rule, considered to have great potential to be malignant. |
