CT appearances of involvement of the peritoneum, mesentery and omentum in Wilms' tumor.

Abstract

Peritoneal involvement by Wilms' tumor indicates stage III disease. CT is the single preferred modality in determining the extent and staging of Wilms' tumor; however, the CT appearances of Wilms' tumor involvement of the peritoneum have not been specifically addressed in the literature. The objective of this study was to demonstrate the CT manifestations when there is involvement of the peritoneum, mesentery and/or omentum in Wilms' tumor. Four cases of Wilms' tumor form the basis of this report. They were examined on Elscint CT scanners. Masses ("dropped metastases") in the pelvis were present in all four patients. Three patients had masses in the mesentery of the small bowel and sigmoid colon. Infiltration of the greater omentum was identified in two patients as a mantle of tumor separating bowel from the anterior abdominal wall. Ascites was present in two patients. In one patient broad-based solid masses of varying sizes were noted on the parietal and on the visceral surfaces of the peritoneum, and in a different patient a discrete mass was noted in the lesser omentum. The peritoneal spaces, recesses, ligaments and folds are invisible unless invaded by disease which is well demonstrated on CT.