Solid pseudopapillary neoplasm, pancreas type, presenting as a primary ovarian neoplasm

Summary Solid pseudopapillary neoplasm has historically been associated with the pancreas, categorized as a tumor of low malignancy. Recently, solid pseudopapillary neoplasm was reported to arise as a primary ovarian tumor in 3 women. We report a fourth case identified in a 48 year-old woman with an 8-cm left ovarian mass. A left salpingo-oophorectomy was performed. Microscopic examination demonstrated a predominately cystic neoplasm comprised of solid nests of cells with an epithelioid to plasmacytoid appearance, associated with blood vessels, hemorrhage, and degenerative changes, that is, pseudopapillary structures. The tumor cells stained focally for pancytokeratin, progesterone receptor, and CD57 with diffuse nuclear expression of β -catenin. Ki-67 was 5% to 10%. Synaptophysin, inhibin, and E-cadherin stains were negative. Clinical and radiologic follow-up of our patient demonstrated no pancreatic lesions. This is a rare report of a primary ovarian solid pseudopapillary neoplasm. Prolonged follow-up is needed to determine how this case will fare clinically.