Evaluation of villous patterns in tumors of the colon and rectum

Summary and Conclusions

After concluding this report of their comprehensive investigation, the authors made these further observations:

Villous patterns can be found in adenomas, villous adenomas, papillomas, papillary adenocarcinomas and many neoplasms of the colon and rectum.

Villous patterns were observed in 45 per cent of adenomas in their series, usually occurring in large tumors, in the older age group, and associated with greater frequency when there was cellular atypia.

Pedunculated forms may occur and, to make a diagnosis, microscopic as well as macroscopic criteria are essential.

In villous adenomas there is a high incidence of malignant transformation and frequently these lesions are associated with separate benign or malignant tumors of the colon and rectum.

In its pure form, villous papilloma is a tumor that is relatively rare and it behaves, essentially, like a villous adenoma.

A negative biopsy does not exclude the possibility that malignant change may exist in another portion of a villous adenoma.