Adenocarcinoma With Breast/Adnexal and Upper Gastrointestinal Differentiation Arising in an Ovarian Mature Cystic Teratoma: A Case Report and Review of the Literature.

Mature cystic teratomas are the most common type of ovarian germ cell tumors. In about 1% of cases, usually among postmenopausal women, a mature cystic teratoma can undergo malignant transformation. Among malignant transformations, squamous cell carcinoma is the most common histology, comprising approximately 80% of cases. In this report, we present the unique case of a 55-yr-old woman with a pelvic mass found to be a mature cystic teratoma with malignant transformation to adenocarcinoma with breast/adnexal, upper gastrointestinal, and neuroendocrine differentiation. The predominant malignant component was the adenocarcinoma exhibiting breast/skin adnexal differentiation, which was found to involve the omentum and a right para-aortic node. We provide an in-depth review of the pathologic findings, as well as a review of the current literature on malignant transformation to adenocarcinoma. This report aims to open a conversation regarding the management of these patients, with a specific focus on the role of molecular analysis and targeted therapies.