What are the other Names for this Condition? (Also known as/Synonyms)

• Villous Adenoma of Urinary Bladder
• Villous Tumor of Urinary Bladder

What is Villous Adenoma of Bladder? (Definition/Background Information)

• Villous Adenoma of Bladder is an exceedingly rare tumor arising in the urinary bladder, from the urothelium (the urothelial cells that line the urothelial tract). Most of the cases are observed in adults; an age range of 23-94 years is noted (average age 62 years) with a male predominance
• Some tumors are observed in the urachus (tubular structure that forms during early fetal development). Although villous adenomas may arise anywhere within the genitourinary tract, these tumors are similar to villous adenomas seen in the large intestine/colon. These adenomas are generally considered to be premalignant tumors, meaning these may turn cancerous over time if left untreated
• The exact cause of formation of Villous Adenoma of Bladder is presently not well-understood. The risk factors include intestinal metaplasia of the bladder lining (in some cases), and surgical procedure to make the urinary bladder larger (called augmentation cystoplasty)
• It is believed that the tumor forms from embryological remnants (cloacal rest) that are abnormally placed in the urinary bladder during fetal formation. Some researchers speculate that it may develop from chronic irritation of the bladder. Mutations in certain genes, such as APC, ATM, KMT2D, PRKDC, and ROS1, have been documented
• The signs and symptoms of Villous Adenoma of Bladder may include blood in urine (hematuria), mucus in urine (mucusuria), burning sensation/discomfort on urination, and abdominal pain. The tumor may be seen alongside low-grade (commonly) and high-grade dysplasias, malignancies, such as in situ or invasive adenocarcinomas (in about 35% of the cases), including sometimes concurrently with urothelial carcinomas
• Isolated Villous Adenomas of Bladder have excellent prognosis when removed completely via surgery. However, in case of an associated adenocarcinoma, the overall outcomes depend on several factors including the type and stage of the tumor. Villous adenomas coexisting with urothelial carcinomas typically present an unfavorable prognosis. Some tumors are also known to progress to malignancies