Benign Tumors of the Bladder

1. Benign Tumors of the Bladder

2. Benign Tumors of the Bladder Epithelial Metaplasia Leukoplakia Inverted Papilloma Papilloma Nephrogenic Adenoma Cystitis Cystica and Glandularis Leiomyoma

3. Inverted Papilloma

4. Inverted Papilloma •Rare, ~1% of urothelial neoplasms seen over a wide age range •Cystoscopy shows small (<3 cm) solitary sessile lesion or may have a short stalk. •Histology: ◦Urothelium invaginates into lamina propria (inverted). ◦Characterized by cords or trabeculae with peripheral palisading of basal cells and central streaming cells. ◦Cords should be thin (a must, to distinguish from higher grade inverted urothelial neoplasms). ◦Bland cytology, but may have scattered degenerative atypia. •Negligible recurrence rate (<1%).

5. Inverted Papilloma

6. Inverted Papilloma • Benign proliferative lesion (associated with chronic inflammation or bladder outlet obstruction) • Can be located throughout the bladder but most commonly on the trigone, comprising less than 1% of all bladder tumors • Inverted growth pattern (anastomosing islands of histologically and cytologically normal urothelial cells invaginating from the surface urothelium into the lamina propria but not into the muscularis propria)

7. Inverted Papilloma • Behave in a benign fashion with only a 1% incidence of tumor recurrence. • Occasionally, present with coexistent urothelial cancer elsewhere in the urinary system, occurring more commonly in the upper tract than the bladder • The use of fluorescent in-situ hybridization (FISH) to evaluate chromosomal changes can distinguish between an inverted papilloma and a urothelial cancer with an inverted growth pattern (Jones et al, 2007). • Transurethral resection is the treatment of choice.