RECTUM - Villous adenoma

The specimen shows a short length of rectum. A 5cm sessile tumour is present on the mucosa. The tumour has a fine papillary surface. There was no microscopic evidence of invasion of the bowel wall.
This man, aged 72, gave a history of altered bowel habits for three to four months. Rectal examination revealed the tumour. The histology of the lesion is that of a villus adenoma; the appearances are described as "delicate villus processes covered tall mucous-secreting columnar epithelium". To be classed as an adenoma adenomatous polyp, the epithelium would have to have shown dysplasia (either low grade or high grade dysplasia).