villous adenoma


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Related to villous adenoma: tubular adenoma

villous adenoma

[′vil·əs ‚ad·ən′ō·mə]
(medicine)
A slow-growing, potentially malignant neoplasm of the mucosa of the rectum; manifested by bleeding and mucoid diarrhea.
References in periodicals archive ?
Villous adenoma in the urinary bladder is morphologically identical to that occurring in the gastrointestinal tract, and 50% of cases have an associated malignancy.
However, bland cytology and distinct architectural differences from the villous adenoma may help in identifying the metaplastic lesion.
Flow cytometry analysis shows DNA aneuploidy in the villous adenoma.
There are no specific imaging findings on CT scan for villous adenoma of the renal pelvis.
12] Given that this villous adenoma has the unusual combination of location in the upper urothelial tract and morphologic similarity to colorectal dysplasia and adenocarcinoma, we hypothesized that a defect in mismatch repair proteins may be present.
Six of these lesions were tubular adenomas, one with atypia, and two were tubular villous adenomas, one with atypia (Table 2).
This patient also had five other lesions in the same area; one was a tubular adenoma without atypia and four were villous adenomas without atypia.
In the 1960s and 1970s, doubts began to surface about the malignant nature of these seemingly noninvasive tumors, and they were reclassified as mucinous cystadenomas or villous adenomas of the appendix, in keeping with the nomenclature for colorectal adenomatous polyps.
From a pathologist's point of view, it is now widely recognized that some types of hyperplastic/serrated polyps represent neoplastic precursor lesions that do not possess conventional morphologic features of dysplasia, characteristic of sporadic tubular or villous adenomas.
We agree with Yokoo et al[1] that the great majority of colorectal polyps can easily be classified as tubular or villous adenomas and hyperplastic polyps.
Predominant staining of the luminal surface nuclei characteristic of tubular and villous adenomas was seen only in the focus of high-grade dysplasia.