A Case Report to Reflect on the Origins of MMRd Mesonephric-like Ovarian Adenocarcinoma: Can It Be Defined as a Mϋllerian Neoplasm?

Mesonephric-like adenocarcinoma (MLA) of ovaries is a new and rare neoplastic entity, recently classified by the World Health Organization. Its morphological and immunohistochemical profile is similar to primitive cervical mesonephric adenocarcinoma, but its origin has not been determined yet. Some authors believe that this neoplasm originates from Wolffian remnants in the ovarian hilum, while others suggest an origin from the Mϋllerian epithelium, followed by a mesonephric trans-differentiation. Starting from a recently diagnosed mismatch repair-deficient ovarian MLA, we try to further develop this line of research. A detailed molecular analysis of the studied tumor helps clarify our ideas. In fact, the typical KRAS mutation was not present. We found mutations in numerous other genes, which are rarely described in the literature or are already described in the endometrioid histotype. We reached some interesting conclusions, which, if supported by future studies, will clarify the true nature of these tumors, allowing for better stratification and a better therapeutic framework.