显微镜下，左侧见绒毛状腺瘤边缘，右侧见突破基底膜。菜花样外观是由于伸长的腺体结构被发育异常的上皮覆盖。虽然绒毛状腺瘤不如腺瘤息肉那么常见，但更有可能恶变为癌（大约40%的绒毛腺瘤）。
Microscopically, a villous adenoma is shown at its edge on the left, and projecting above the basement membrane at the right. The cauliflower-like appearance is due to the elongated glandular structures covered by dysplastic epithelium. Though villous adenomas are less common than adenomatous polyps, they are much more likely to have invasive carcinoma in them (about 40% of villous adenomas).
