大腸多発ポリープに認められたⅡc様大腸早期癌の2病変

Two Lesions of Ⅱc-like Early Colonic Cancer Associated with Multiple Polyps of the Large Intestine: Report of a case

　近年早期大腸癌症例が多く報告されているがそのほとんどが隆起性である．大腸早期癌の組織発生については腺腫adenomaが注目されているがde novo cancerについても完全に否定されていない．

　われわれは下行結腸およびS状結腸の多発ポリープとして診断し結腸切除術を行った切除標本にきわめてまれなde novo cancerと思われるⅡc様病変（m癌）を2カ所に認めたので報告する．

　Most of early Colonic cancer cases hitherto reported were of the protruded types, and depressed types have been reported rarely. Even the latter cases were mostly associated with invasion into the submucosa. Adenoma is being regarded as the source of carcinogenesis of early Colonic cancer. It has not completely been denied that adenoma has also something to do with de novo cancer.

　The present case shows two lesions of Ⅱc like early colonic cancer which is assumed to be de novo cancer, complicated with multiple polyps.

　The patient was a 55-year-old male with a chief complaint of bloody stool of about 6 months duration. He had no hereditary disease. He was hospitalized on May 25, 1977, and polyps of little finger head size up to soybean size were detected in the descending colon and sigmoid colon through barium enema.

　With diagnosis of multiple polyps, colectomy was performed.

　The resected specimen showed 10 polyps of little finger head size down to rice grain size and two lesions of depressed type (Ⅱc) measuring 1.1×1.2 cm and 0.6×0.7 cm, respectively.

　The histologic findings were that, of 10 polyps of pedunculated or sessile type, four were identified as cancer in adenoma, and both of the Ⅱc lesions were diagnosed as well-differentiated adenocarcinoma limited within the mucosa.

　Back-to-back arrangement, trend to intraglandular budding, disorganization of cells or nuclei, and dark staining of nuclei were also recognized. Invasion into the muscularis mucosae was also partly found out, but the disturbance were not beyond the muscularis mucosae. Findings of adenoma were not seen in the surrounding mucosa of the lesions.