Cystitis cystica is a common incidental finding, most commonly at trigone or bladder neck, and often in response to chronic irritation or previous inflammatory insult.
- Caused by proliferation of the urothelium into buds, which grown downwards into lamina propria, differentiating into cystic deposits.
- There is no pre-malignant potential for cystitis cystica.
- Cystoscopically appears as translucent small submucosal cysts.
- Ureteritis cystica is the same condition, seen in the ureter.
Cystitis glandularis is a similar process but the invaginated urothelium undergoes glandular metaplasia (into columnar or cuboidal cells).
- It is a pathological spectrum with cystitis cystica, and the co-existence of both can be called cystitis cystica et glandularis.
- Some texts suggest an association with adenocarcinoma, probably more with the intestinal type – consider follow up for diffuse cystitis glandularis.
Intestinal metaplasia (glandular metaplasia) is the replacement of urothelium by colonic mucosa or goblet cells. Sometimes referred to as cystitis glandularis of intestinal type.
- It is often an incidental finding, increasing with age, but can also be a response to inflammation.
- Surveillance probably warranted given an unclear association with adenocarcinoma, seemingly stronger than usual cystitis glandularis.
Von Brunn nests are nests of cytologically benign urothelium in the lamina propria.
Squamous metaplasia is usually seen in female trigone and is essentially a normal variant. It is non-keratinising.
- Keratinising squamous metaplasia (leukoplakia) is rare, can affect the entire bladder and is considered possibly premalignant.