Villous Adenoma Arising in the Native Bladder Mucosa and the Upper Urinary Tract With Coexisting Neuroendocrine Carcinoma Following Augmentation Cystoplasty

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 the renal pelvis: a common entity at an uncommon location

Villous adenoma is uncommonly seen in the urogenital tract and is even more rarely seen in the upper urinary tract and renal pelvis. Like colorectal adenomas, these neoplasms can transform into adenocarcinoma. The preoperative diagnosis is challenging due to their frequent association with hydronephrosis. Herein, we present the case of a villous adenoma of the renal pelvis in a 62-year-old man presenting with recurrent urinary tract infection. The computed tomography scan showed marked hydronephrosis but no suspicious mass in the right kidney. A laparoscopic right nephrectomy was performed. Gross examination revealed a dilated renal pelvis with an irregular exophytic lesion in the renal pelvis’s upper surface. The histopathological examination showed slender, elongated villi with thin fibrovascular cores, consistent with villous adenoma morphology. Isolated villous adenomas have a favorable prognosis. However, the pathologist should undertake a search for an invasive component.

Villous Adenoma Arising in the Urethra of a Female with Bladder Augmentation History: A Case Report and Review of the Literature

Villous adenomas (VAs) in the female urethra are rare with only seven cases in the English literature to our knowledge. In patients with bladder augmentation cystoplasty, the neoplasia development risk increases and most of these develop in the neobladder or anastomosis line. Only two cases of VA developing from the native bladder mucosa have been reported. Physical examination of a 76-year-old female who had a history of augmentation cystoplasty revealed a caruncula-like structure protruding from the urethral meatus. The urinary USG showed that the lesion had no relation with the bladder. The lesion was excised. Microscopically, it consisted of villous structures covered with pseudostratified intestinal type epithelium. Low-grade dysplasia was present in the epithelium but high-grade dysplasia or in-situ/invasive carcinoma was not observed. Immunohistochemical study showed positivity for CK7, CK20, EMA, CEA and CDX2. The case was reported as VA of the urethra. We presented the first VA case arising in the urethra of a female patient with intestinal bladder augmentation. Excision is curative for pure VAs. Transformation to carcinoma or recurrence has not been reported. However, in one third of the cases, a malignant tumor may accompany the lesion. Therefore, all excision material should be examined carefully. Routine endoscopic follow-up should be performed in cases with bladder augmentation.