Gastric-type endocervical adenocarcinoma with uterine corpus involvement mimicking primary endometrial carcinoma

Differentiation of endocervical adenocarcinomas involving the uterine corpus from primary endometrial (EM) carcinomas involving the cervix is, not only clinically but also pathologically, often difficult. We report a case of gastric-type endocervical adenocarcinoma involving the corpus that could be correctly diagnosed because it was a unique endocervical adenocarcinoma subtype. A 69-year-old woman who presented with abnormal genital bleeding was diagnosed as having a uterine adenocarcinoma on pathological examination of EM biopsy. Preoperative imaging findings and a surgical specimen showed that the tumor was mainly located in the corpus and involved the cervix. We considered at first that the tumor was an EM adenocarcinoma invading into the cervix. However, results of an immunohistochemical examination indicated that it was a gastric-type mucinous adenocarcinoma derived from the endocervix. Our final pathological diagnosis was a gastric-type endocervical adenocarcinoma spreading to the uterine corpus.