17^th European Pathology Congress

Biography

Biography: Doughty ES

Abstract

During female embryologic development, the absence of testosterone promotes mesonephric (Wolffian) duct involution. Mesonephric remnants persist and can, rarely, undergo transformation to mesonephric adenocarcinoma (MA), an aggressive neoplasm difficult to differentiate from female adnexal tumor of probable Wolffian origin (FATWO), a neoplasm of uncertain origin. MA and FATWO have similar morphologic and immunohistochemical (IHC) features, suggesting that these may represent the same entity. We present a case of FATWO and a case of MA, examining differences in morphology/IHC findings. Case 1: Seventy four-year-old woman with a large pelvic mass involving the left adnexa and colonic serosa. Microscopically, the infiltrative mass displayed retiform architecture with intraluminal eosinophilic acellular material, significant mitotic activity, and necrosis. IHC results: WT-1 positive, PAX-8 negative and GATA3 negative. The tumor was diagnosed as malignant FATWO. Case 2: Sixty one-year-old woman with bilateral ovarian masses, omental caking and ascites. The tumor was heterogeneous with prominent retiform and papillary architectures, clear cell change, abundant mitoses and no necrosis. IHC results: WT-1 negative, PAX-8 positive and GATA3 focal positivity. The tumor was initially diagnosed as malignant FATWO. The patient initially responded to platinum-based adjuvant chemotherapy, but recurred four months following treatment. Subsequent genetic tumor testing on the primary surgical debulking specimen demonstrated a NRAS mutation, consistent with MA. We propose that MA and FATWO are distinct entities and that the WT-1/PAX-8/GATA3 immunoreactivity pattern and NRAS mutation can help in the diagnosis of FATWO and MA. These two cases highlight the utility of IHC and genetic analysis in the distinction of these two entities.