Endometrial Metastasis from Primary Rectal Carcinoma:A Case Report and Literature Review

Metastases to the uterine endometrium from an extra genital site are a rare event. As in primary endometrial carcinoma, abnormal uterine bleeding is the most common symptom of such metastases. The misdiagnosis of another original cancer as a primary endometrial carcinoma should be avoided. Here we report a case of endometrial metastasis from a primary rectal carcinoma. A 63-year-old Japanese woman was admitted to our hospital with postmenopausal abnormal uterine bleeding. Endometrial cytology revealed an adenocarcinoma. Endometrial sampling showed multiple fragments of proliferative endometrial tissue mixed with irregular glands lined by atypical cells with elongated, hyper chromatic nuclei and solid sheets of neoplastic cells. The neoplastic glands were positive for CDX2 and CK20 and negative for CK7. The tumor was histologically diagnosed as metastatic endometrial carcinoma originating in the rectum. The endometrial metastasis was treated solely by tumor removal. Although rare, extra genital sites should be considered as possible primary sites of metastatic endometrial carcinoma. In addition to the clinical history, a thorough histological examination including immunohistological staining is necessary to diagnose metastatic carcinoma.