Diagnostic radiologic features of pseudomyxoma peritonei consist of diffusely scattered plaques of calcifications in the abdomen, poorly defined soft tissue masses and ascites on plain abdominal radiographs, characteristic scalloping of the hepatic margin, numerous multilocular cystic masses with rims of curvilinear calcifications and compression of abdominal viscera without evidence of invasion at computed tomography, and an echogenic mantle with ascitic septations at ultrasonography. In an appropriate clinical setting, this spectrum of radiologic features is highly specific for the diagnosis of pseudomyxoma peritonei.