Colon cancer with micropapillary carcinoma component: a clinopathologic study of 9 cases.

Recently, colon cancer with micropapillary pattern (MPP) has been identified. MPP is defined as tight tufts surrounded by cleft-like space and lacking true fibrovascular cores and showing reverse polarity. In this article, we studied nine cases of colon cancer with MPP. MPP usually accounted for a minor component in total tumour volume, which ranged from 3 to 40% with a mean percentage of 19.2%. Associated histological subtype showed moderately differentiated tubular adenocarcinoma in all cases. The reverse polarity of villin (9/9, diffuse) in MPP component was superior to that of CA125 (5/9, focal) or CD10 (5/9, diffuse 2/9, focal 3/9). In clinicopathological indicators such as sex, tumour location, tumour depth, lymphovascular invasion, lymph node metastasis, or pathological stage and clinical behaviour, there was statistically no difference between the MPP group and the non-MPP group of the colon. In conclusion, colon cancer with MPP is characterised by frequent association with moderately differentiated tubular adenocarcinoma as a minor component. Villin immunohistochemistry is useful in the detection of reverse polarity of MPP of colon cancer.