LAUSR

Primary peritoneal serous carcinoma (PPSC) is a rare neoplasm histologically indistinguishable from ovarian serous carcinoma primarily occurring in the female population. To date, extremely rare cases of PPSC have been reported in men; however, diagnosis by cytology has yet to be described. Here we present the clinical, radiographic, cytomorphologic, histologic and immunohistochemical (IHC) findings of a high-grade (HG) PPSC in a 70-year-old man with a history of prostatic adenocarcinoma. Core needle biopsy (CNB) touch preparation smears showed pleomorphic, round, columnar and polygonal epithelioid cells present singly or arranged in loosely cohesive three-dimensional clusters. The tumor cells are characterized by enlarged nuclei containing prominent nucleoli, and variable scant to moderate, slightly dense cytoplasm. Scattered cells contained cytoplasmic vacuoles. Examination of CNB revealed an infiltrating tumor in sheets with focal papillary configuration. Tumor cells were morphologically consistent with HG carcinoma. IHC studies demonstrated diffuse positivity for CK7, PAX-8, ER, WT1, p53, p16 and BerEP4 with focal/weak staining for calretinin and CK5/6, which supporting the diagnosis of HG PPSC. The patient was treated with 6 cycles of carboplatin and paclitaxel with near resolution of the mass at 10 month follow-up. To the best of our knowledge, this is the first reported case in the literature of PPSC in a man diagnosed by cytology. This article is protected by copyright. All rights reserved.