Urinary bladder: Congenital anomalies

• congenital--may be due to a focal failure of development of the normal musculature or to some urinary tract obstruction during fetal development

• acquired--seen most often w/prostatic enlargement, producing obstruction to urine outflow & marked muscle thickening of the bladder wall; increased intravesical pressure causes outpouching of bladder wall & formation of diverticula

Know the complications of bladder diverticula: stone and urinary infection.

• diverticula constitute sites of urinary stasis and predispose to infection and formation of bladder calculi; may predispose to vesicoureteral reflux; rarely, carcinomas may arise in diverticuli.

Know the pathology of bladder extrophy and complications (mucosal metaplasia, development of cancer and urinary infection) of bladder extrophy.

• pathology--implies the presence of a developmental failure of the anterior wall of the abdomen and the bladder; bladder can communicate directly through large defect w/ surface of body or can lie as an opened sac

• complications--may undergo colonic glandular metaplasia; is subject to development of infections (may spread to upper urinary system) if infections are chronicmucosa often becomes an ulcerated surface of granulation tissue and preserved marginal epithelium becomes transformed into a stratified squamous type; increased tendency later in life to carcinoma (mostly adenocarcinoma)

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Know other congenital anomalies: vesicoureteral reflux, fistulas, partial and total persistent urachus. What are the complications of persistent urachus?

• vesicoureteral reflux--most common and serious; major contributor to renal infection and scarring.

• fistulas--abnormal connections between bladder and vagina, rectum or uterus

• total persistent urachus--when totally patent, fistulous urinary tract is created that connects the bladder w/ the umbilicus

• partial urachus--umbilical end or bladder end is patent but central region is obliterated. sequestered umbilical epithelial rest or bladder diverticulum is formed (may provide site for infection); central region of urachus may persist => urachal cysts lined by transitional or metaplastic epithelium. carcinomas (mostly glandular) can arise in these cysts--only 0.1-0.3% of bladder CA but 40% of bladder adenocarcinoma.

Category: Pathology Notes