Metaplasia of the urothelium to squamous epithelium in the urinary bladder most commonly indicates which underlying etiology in endemic regions?

• A Urothelial carcinoma in situ progressing to squamous differentiation
• B Vitamin A deficiency causing widespread squamous metaplasia
• C Chronic Schistosoma haematobium infection ✓
• D Cyclophosphamide-induced chemical cystitis

Explanation

Squamous metaplasia of the bladder urothelium in endemic regions is classically associated with chronic Schistosoma haematobium infection, which is a major risk factor for squamous cell carcinoma of the bladder. The chronic inflammatory stimulus from schistosomal eggs lodged in the bladder wall drives urothelial metaplasia to squamous epithelium. Cyclophosphamide causes hemorrhagic cystitis and increases risk of transitional/urothelial carcinoma, not squamous metaplasia.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.