Recurrent Primary Peritoneal Psammocarcinoma: A Case Report on a Diagnostic Challenge in Cytology.

Psammocarcinoma (PCa) is a rare variant of low-grade papillary serous carcinoma that can arise from the peritoneal as well as ovarian surfaces. When this tumor involves the extra-ovarian peritoneum significantly and the ovarian surface minimally or not at all, it is considered of peritoneal origin. PCa has a recurrent indolent clinical course. It is challenging to diagnose peritoneal PCa, particularly on cytological smears because of the bland cellular features of neoplastic cells. We report a case of recurrent metastatic primary peritoneal PCa in a 71-year-old female of Ashkenazi Jewish ancestry diagnosed on cytology of ascitic and cystic fluid.