Villous Morphology in Urinary Bladder Biopsy: An Approach to Diagnosis

Abstract

Villous morphology in urinary bladder biopsy is a relatively uncommon finding. Villi are slender, finger-like structures that are commonly seen in the small intestine or in neoplastic lesions of gastrointestinal lineage/differentiation. Importantly, placenta also exhibits villi that are morphologically and functionally different from the intestinal one. Majority of the neoplastic lesions of urinary bladder are urothelial in origin with a minor subset showing glandular differentiation. While the presence of benign villi in urinary bladder biopsy necessitates a search for an occult perforation, provided a sample mismatch is ruled out, cytoarchitecturally abnormal/dysplastic villi indicate a neoplastic lesion of the urinary bladder encompassing villous adenoma and adenocarcinoma and urothelial carcinoma with villoglandular differentiation. The dysplastic villi in urinary bladder also imply a lower gastrointestinal endoscopy to rule out a colorectal primary. The development of the villous lesions in the urinary bladder and the colorectum are embryologically related and pose a major diagnostic challenge to the clinicians and surgical pathologists due to identical histomorphology and immunohistochemistry. We tend to discuss the morphological differentials and diagnostic approach to the villous lesions in the urinary bladder biopsy.

Villous adenoma of bladder with uncommon location in a super‐aged patient without gross hematuria

“…All immunohistochemistry of villous adenoma was positive for CK20 with complete membranous and intense signal. However, 33–50% of the cases were positive for CK7 with incomplete membranous and less intensity signal 6 . Absence of GATA3 and p63 expression can distinguish villous adenoma from urothelial carcinoma 7 .…”

Traditional Serrated Adenoma of the Urinary Bladder: The First Report

“…1 Intestinal type glandular neoplasms of the urinary tract are very rare and described as tubular adenoma or tubulovillous adenoma and adenocarcinoma. 2 Although villous adenoma is the most common intestinal type lesion in the urinary system, villous adenoma arise infrequently in the urinary bladder. To date, two case series from Mayo Clinic (23 cases), 3 and Johns Hopkins University (18 cases) 4 and individual case reports were published in English literature.…”

“…Tubular adenoma and villous adenoma infrequently arise in the urinary bladder. 2 Serrated lesions/polyps, newly described discrete type of intestinal lesions, have not been reported in the urinary tract. Here, we report the first example of traditional serrated adenoma (TSA) arising from intestinal metaplasia in the urinary bladder.…”