Unusual origins of Pseudomyxoma peritonei.

Pseudomyxoma peritonei is a rare neoplastic condition in that gelatinous intraperitoneal fluid collections and mucinous implants on the peritoneal surfaces and omentum are found. The pathological origin is usually an adenoma or well-differentiated adenocarcinoma of the appendix. A smaller number of cases arises from ovarian tumors. We report two unusual cases of pseudomyxoma peritonei. As a child, the first patient underwent several surgical procedures of the large bowel to relieve the consequences of Hirschsprung disease that were complicated by recurrent enteric fistulae. Colonic epithelial cells, with neoplastic changes due to chronic inflammation in the presence of enteric fistulae, were probably dislocated during these episodes, causing pseudomyxoma peritonei. In the second patient, pseudomyxoma was caused by intraperitoneal seeding of a mucinous urachal adenocarcinoma. We hypothesize that seeding of mucus producing epithelial cells into the abdominal cavity may result in this rare entity called pseudomyxoma peritonei, regardless of the source. Copyright 2000 Wiley-Liss, Inc.