CT diagnosis of villous adenoma.

Villous adenoma may have a specific appearance on barium enema examination but specific CT findings of villous adenoma have not been previously described. Two recently encountered cases of villous adenoma in the rectum had a distinctive pattern on CT. Suggested criteria for CT diagnosis of villous adenoma include a homogeneous water density component of less than 10 HU, occupying more than half the lesion and eccentric on the luminal side of the mass. This low density component interfaces with the majority of the luminal surface of the lesion. No air-fluid level is seen and the lesion should not have a round cystic configuration. A description of these findings is illustrated and discussed.