大腸villous tumorの病理診断

Histopathological Diagnosis of the Colorectal Villous Tumor

要旨　われわれの経験した大腸腺腫症例の亜分類を行い，それらと癌との関係を統計的に解析した．1975年末までの国立がんセンターの手術例の集計によると，大腸腺腫性ポリープ111病巣中4病巣（3.6％）が絨毛腺腫であった．1985年末までのポリペクトミー材料の集計によると483個のうちわずかに3個（0.6％）と極めて低率である．一方，多かれ少なかれ絨毛成分を有している腺管絨毛腺腫の頻度は比較的多く163個（33.8％）で，癌化率も34.4％と比較的高かった．1985年末までに経験した早期大腸癌164例177病巣について大きさ別に腺腫成分の共存率をみた．典型的な絨毛腺腫との共存例は少なく8病巣（4.5％）であったが，腺管絨毛腺腫は84病巣（47.5％）とかなり高率であった．このことは現在までに発見されている早期大腸癌は絨毛腺腫より腺管絨毛腺腫を前癌病変としているものの占める割合が高い．

　The incidence of the colorectal carcinoma, especially carcinoma in the sigmoid colon has been increasing in Japan recently. Needless to say, adenoma is considered to be an important precancerous lesion of the colorectal carcinoma. In this paper, the relationship between adenoma and carcinoma was described based on our materials experienced.

　The frequency of the villous tumor was 3.6%, i.e., only four villous tumors found among 111 polyps resected surgically, during the period from 1962 to the end of 1975. However, among 483 polypectomized lesions during the period from 1962 to 1985 in our hospital, the villous tumor was noted in only three lesions (0.6%). Villous tumor was more frequently seen in the older age group than in the younger age group. It occurred most frequently in the recto-sigmoid region. A macroscopic feature typical to the surgically resected villous tumor was broad-based elevation in shape. Histological examination revealed numerous delicate vertical or radiated linear projection of the neoplastic epithelium from the fibrous core or lamina muscularis mucosae.

　Tubulo-villous adenoma, a mixed lesion of tubular and villous adenomas, was seen in 163 (33.8%) out of 483 polypectomized lesions. The coincidence rate of carcinoma in tubulo-villous adenoma was relatively high (34.4%). On the other hand, the incidence rate of carcinoma occurring in the typical villous tumor was low, i.e., 8 (4.5%) out of 177 lesions experienced in our hospital during the same period. Again the coincidence rate of tubulo-villous adenoma with carcinoma was high, i.e., 47.5% of the same series of lesions.

　These findings lead to the speculation that tubulo-villous adenoma is more important as a precancerous lesion than villous adenoma.