Bladder Diverticulum : Histology

Histology: The diverticular wall is usually thin and consists of mucosa, subepithelial connective tissue (lamina propria), scattered disorganized thin muscle bundles, and an adventitia that may form a fibrous capsule or pseudocapsule. Muscularis propria (Detrusor muscle) is absent. The mucosal lining initially consists of urothelium. Over time, chronic inflammation may lead to atrophy (shown here) or metaplastic changes, including squamous metaplasia (next image) and intestinal metaplasia. Due to disorganized and non-functioning smooth muscle in the wall, the bladder diverticula do not empty fully during micturition, leaving a large volume of residual urine that predisposes to infection and stone formation.