Villous Adenoma : High-grade Dysplasia
Villous adenomas with high-grade dysplasia show prominent nuclear enlargement, pleomorphism and hyperchromasia, enlarged nucleoli, and further loss of goblet cell mucin. There is considerable hypercellularity and glandular crowding. There is increased mitotic activity and atypical mitoses may be present. The degree of dysplasia and the assessment of the villous component in adenomas suffer from considerable interobserver variability; however, they should be reported. The adenomas that are greater than 1 cm in size, have a significant villous component or high-grade dysplasia or carcinoma are labeled “adenomas with advanced pathology” and are subjected to closer endoscopic surveillance due to high risk of development of carcinoma. The image shows low-grade dysplasia (mild to moderate) on the left and high-grade dysplasia (severe) on the right. Both fields are from the same case.