Pseudomyxoma is a clinical entity in which the peritoneal surfaces and
omentum are involved with gelatinous, mucinous implants, and often ma
ssive gelatinous ascites. Most cases originate from ruptured ovarian c
ysts or appendiceal mucoceles, and involve only the intraperitoneal ca
vity. This report describes a case of disseminated adenomucinosis, the
benign form of pseudomyxoma, with both peritoneal and retroperitoneal
involvement. The diagnosis was suggested by real-time ultrasound and
confirmed at surgery. The ultrasound characteristics of this rare enti
ty and the differential diagnoses are discussed.