8480/6 Pseudomyxoma peritonei


Definitions

Retroperitoneum and peritoneum
ICD-O-3 topography code: C48

A well differentiated mucinous adenocarcinoma of the peritoneum. The vast majority of cases represent tumor spread from a primary well differentiated mucinous adenocarcinoma of the appendix. Cases of pseudomyxoma peritonei associated with mucinous adenocarcinomas of the gallbladder, stomach, colon, rectum, pancreas, lung, breast, and fallopian tubes have also been reported. In the past, the ovary has been considered as a common primary site associated with pseudomyxoma peritonei. However, there is recent evidence based on immunohistochemistry and molecular genetic analysis suggesting that most cases of pseudomyxoma peritonei probably represent metastasis from an appendiceal and not ovarian primary.