Use of transrectal ultrasonography to select type of surgery for villous tumors in the lower two thirds of the rectum.

Abstract

To determine the accuracy of transrectal ultrasonographic (TRUS) staging of rectal villous tumors when used to select a surgical procedure. Case series. College hospital, Hyogo, Japan. From 1988 to 1995, 24 patients were treated for villous tumors after diagnosis by TRUS, and were followed up for 0.5 to 7.5 years. Ultrasonographic tumor stage (u-T), pathologic tumor stage (p-T), biopsy findings, and surgical procedures were studied. Overall, 71% of the tumors were accurately staged by TRUS. However, 4 u-T1 and 3 u-T2 tumors were overstaged, with pathological examination showing 2 adenomas and 5 p-Tis tumors. Three of these 7 patients were overtreated surgically. The results of a biopsy predicted adenoma in 2 of the u-T1 tumors and 2 of the u-T2 tumors that were overstaged by TRUS. Pathological examination revealed that an enlarged lymphoid follicle in the mucosa had deformed the thin muscle layer of the rectal wall and abolished its continuity on TRUS imaging. The weakness of TRUS would seem to be in the accuracy of p-Tis staging. Transrectal ultrasonography had the advantage of predicting malignant infiltration in rectal villous tumors. The surgeon should know the limitations of TRUS diagnosis to select the most appropriate operation for each patient.