CT manifestations of peritoneal leiomyosarcomatosis.

Peritoneal leiomyosarcomatosis causes multiple discrete tumor nodules in the peritoneum, mesentery, and omentum with or without evidence of a primary site. The CT and pathologic findings in seven patients with this disease were reviewed. All seven patients had CT evidence of multiple, discrete peritoneal masses, and five patients showed a central low-attenuation area. CT grade of malignancy in peritoneal tumors was categorized as low (four patients) and high (three patients) on the basis of the degree of central necrosis of the tumors. The CT results correlated with the histopathologic grade of malignancy, although all tumors were grade 2 or higher histopathologically. Ascites and lymphadenopathy were not present in any of the patients. Liver metastases were identified in five patients with central necrosis of the metastases evident in four. The presence of liver metastases and the degree of central necrosis in the liver metastases did not correlate with the size or histologic grade of the primary tumor. Although uncommon, peritoneal leiomyosarcomatosis should be considered when CT shows multiple, discrete peritoneal masses with central necrosis and liver metastases in the absence of ascites and lymphadenopathy.