Ovarian Mesonephric-Like Adenocarcinoma Arising Within a Serous Borderline Tumor: Insights into the Implications of Cell Origin—A Case Report and Review of the Literature

BackgroundMesonephric-like adenocarcinoma (MLA) is a rare and aggressive tumor found in the uterus and ovaries, characterized by unique morphological and immunophenotypic features similar to mesonephric carcinoma. It has been suggested that some tumors of MLA may originate from Müllerian-type lesions.Tumor PresentationA 54-year-old woman presented with abdominal discomfort and adnexal mass. Laboratory results revealed elevated carcinoembryonic antigen and CA-125 levels. Surgical findings showed ovarian MLA arising within a serous borderline tumor (SBT) with metastasis to lymph nodes, classified as FIGO stage IIIA2.Pathological FindingsThe SBT component exhibited typical papillary architecture, while the MLA component showed admixture of various architectural patterns, with intraluminal eosinophilic secretions. Immunohistochemistry revealed positivity for GATA3, TTF-1, and CD10, and negativity for ER and WT1. Molecular analysis identified a <i>KRAS</i> p.G12D mutation, typical of MLA, and a <i>SMAD4</i> mutation.ConclusionThis tumor represents the ninth documented example of ovarian carcinoma with distinct components of MLA and low-grade serous neoplasm, SBT or low-grade serous carcinoma, providing valuable insights into the clinicopathological features and molecular characteristics of MLA, and contributing to the understanding of its origin and clinical behavior.