Villous Morphology in Urinary Bladder Biopsy: An Approach to Diagnosis

Traditional Serrated Adenoma of the Urinary Bladder: The First Report

A 71-year-old woman was hospitalized with hematuria and underwent cystourethroscopy. Cystourethroscopy revealed a polypoid bladder tumor. Histopathologic examination showed complex villiform growth pattern, slit-like serrations, and ectopic crypts lined by epithelium with eosinophilic cytoplasm, pseudostratified elongated nuclei, consistent with traditional serrated adenoma. Nephrogenic and intestinal metaplasia with severe inflammation were present in adjacent bladder mucosa. Molecular study of the polyp revealed mutation (p.G12V) in codon 12 of exon 2 of the KRAS gene. Traditional serrated adenoma is a rare type of colonic serrated polyp, making up less than 1% of the colonic polyps with a predilection to distal colon. In the literature, there is no traditional serrated adenoma reported outside the gastrointestinal tract. Here in we report the first extra-gastrointestinal traditional serrated adenoma within the bladder and bladder diverticulum, arising from intestinal metaplasia. The present study reports an additional information on molecular background of this unusual bladder polyp.

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

INTRODUCTION

There have been few reported cases of villous adenoma of the bladder. It commonly occurs in the superior area of the bladder with hematuria as the most common symptom. Here, we have presented a case of villous adenoma of the bladder neck and reviewed the existing literature.

CASE PRESENTATION

A 90-year-old man presented with voiding difficulty. Although urine analysis revealed microscopic hematuria and pyuria, the patient never complained about gross hematuria. Ultrasonography and cystoscopic examination revealed a bladder tumor located at the bladder neck. Transurethral resection was performed and villous adenoma was diagnosed by histopathologic examination.

CONCLUSION

Villous adenoma of the bladder is a rare disease, which is difficult to diagnose when the patient presents with uncommon clinical features. Although villous adenoma is known as a benign tumor, some reports suggest its association with malignancy. Therefore, careful management and follow-up are necessary.