Atypical Polypoid Bladder Lesion Mimicking Urothelial Carcinoma in a Young Male - A Case Report About a Possible Autoimmune-Triggered Granulomatous Inflammation With Secondary Colonization

Sep 30, 2026

Gross hematuria demands extensive evaluation because it can signal urothelial carcinoma, yet several mimics must be considered, including renal malignancy, infection, urolithiasis, and autoimmune disease. This report describes a 28-year-old man with gross hematuria, flank pain, and dysuria, whose cystoscopic polypoid bladder lesion appeared cancer-suggestive. Histology showed granulomatous inflammation without malignancy, systemic vasculitic features emerged, and corticosteroid therapy led to complete regression of symptoms and the lesion.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages9

Reading Time23 min

AccessFree to download

Abstract

Introduction

Case Presentation

Initial presentation

How to cite this article

Laboratory findings

Review began 10/06/2025 Review ended 12/03/2025 Published 12/10/2025 © Copyright 2025 Hofmann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CCBY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited. DOI: 10.7759/cureus.98879 Open Access Case Report Atypical Polypoid Bladder Lesion Mimicking Urothelial Carcinoma in a Young Male: A Case Report About a Possible Autoimmune-Triggered Granulomatous Inflammation With Secondary Colonization Severin P. Hofmann 1, Uwe Bieri 1, Franz von Stauffenberg 2 , Stefan Schneider 3, Gad Singer 4, Michael Greiner 5, Lukas John Hefermehl 1 1. Department of Urology, Kantonsspital Baden, Baden, CHE 2. Department of Urology, Universitätsspital Zürich, Zurich, CHE 3. Department of Rheumathology, Rheumazentrum Aarau, Aarau, CHE 4. Department of Pathology, Kantonsspital Baden, Baden, CHE 5. Department of Infectious Disease, Kantonsspital Baden, Baden, CHE Corresponding author: Severin P. Hofmann, [severin.hofmann@gmail.com](severin.hofmann@gmail.com) Abstract Gross hematuria is a critical clinical symptom requiring thorough diagnostic evaluation, particularly due to its association with urothelial carcinoma. However, other differential diagnoses must also be considered, including renal carcinoma, infection, urolithiasis, and autoimmune disease. We report the case of a 28-year-old male presenting with gross hematuria, flank pain, and dysuria. Imaging revealed bladder wall thickening and bilateral narrowing of the renal pelvis. Cystoscopy showed a large, polypoid lesion suggestive of urothelial carcinoma. Transurethral resection (TUR-B) was performed ; however, histological analysis revealed granulation tissue with inflammatory infiltrates, multinucleated giant cells, and necrosis but no evidence of malignancy. Metagenomic sequencing identified Peptoniphilus sp. SAHP1, Anaerococcus mediterraneensis, and Trichomonas vaginalis , though their pathogenic role remained uncertain. Shortly after, the patient developed systemic inflammatory symptoms, including exanthema and gingivostomatitis. Biopsy of skin lesions showed leukocytoclastic vasculitis, and serologic testing yielded borderline myeloperoxidase-specific antineutrophil cytoplasmic antibody (MPO-ANCA) positivity. Under corticosteroid therapy, all symptoms, including the bladder lesion, regressed completely. This case highlights a rare constellation of findings mimicking urothelial carcinoma, ultimately pointing toa probable autoimmune vasculitic process with possible secondary microbial colonization. It underscores the diagnostic challenges posed by atypical presentations and the need for integrative interpretation of clinical, histological, and molecular findings in complex cases. Categories: Urology, Pathology, Rheumatology Keywords: gross hematuria, mimicking urothelial carcinoma, polypoid bladder lesion, secondary microbial colonization, vasculitis of the bladder Introduction Atraumatic gross hematuria should always prompt further diagnostic evaluation, as it represents a significant warning sign for various potentially serious conditions. The most critical differential diagnoses in this context include malignant tumors such as urothelial carcinoma and renal cell carcinoma [1-3]. The most common non-malignant differential diagnoses include ureterolithiasis [3,4] and hemorrhagic urinary tract infections [3,5] . IgA nephropathy [6] and lupus erythematosus may also cause macroscopic hematuria [3,7] . Vasculitis is a very rare underlying cause of hematuria. In most of these cases, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides involve the glomerular region of the kidneys and may result inglomerular macroscopic hematuria [8] . Involvement of the urinary bladder is rare and may occur either as part of a systemic vasculitic process or as an organ-limi

FAQs

Why was gross hematuria treated as a critical diagnostic warning in this case?

Gross hematuria is emphasized as a major warning sign linked to urothelial carcinoma, but the report stresses that serious alternatives must also be evaluated, including renal cancer, infection, urolithiasis, and autoimmune disease.

What did histology show after transurethral resection of the bladder lesion?

Histology revealed granulation tissue with inflammatory infiltrates, multinucleated giant cells, and necrosis, with no evidence of malignancy.

How were systemic inflammatory and skin findings explained, and what was the outcome with treatment?

The patient developed systemic inflammatory symptoms and skin lesions consistent with leukocytoclastic vasculitis, with borderline MPO-ANCA positivity. After corticosteroid therapy, all symptoms, including the bladder lesion, regressed completely.

Sep 30, 2026

Uploaded by Maya Linwood