Abstract
We report two cases of micropapillary carcinoma (MPC) of the rectum and reviewed 32 cases from the Japanese literature from 2005 to 2014. Case 1 involved a 63-year-old man who underwent high anterior resection for a diagnosis of rectal cancer with liver metastasis. Histopathological findings showed poorly differentiated adenocarcinoma accounting for most of the tissue, with a potion showing a so-called “inside-out -pattern”. MPC of the rectum was diagnosed. As well as multiple liver metastases, marked lymphatic invasion and multiple lymph node metastases were seen. Case 2 involved a 59-year-old woman in whom rectal cancer was identified during examination of uterine cancer. We planned chemoradiotherapy for the uterine cancer and performed Hartmann's operation for the rectal cancer. In histopathological findings, well to moderately differentiated tubular adenocarcinoma including an MPC component was revealed. Marked lymphatic invasion was present, but no lymph node metastasis. MPC is recognized as a high-grade malignant tumor with a high propensity for lymph node metastasis and distant metastasis. We examined clinicopathological characteristics of MPC of the colorectum.
