Urinary Bladder Pathology

URINARY BLADDER PATHOLOGY

Congenital anomalies of the bladder. Exstrophy of the bladder is a developmental failure of the formation of the abdominal wall and bladder which leaves the blad-der open at the body surface. Urachal cyst remnants may permit drainage of urine from a newborn’s umbilicus, and may also be a cause of bladder adenocarcinoma.

Cystitis. The etiology of cystitis varies, with important causes including organ-isms, notably from fecal flora (Escherichia coli, Proteus, Klebsiella, Enterobacter); radiation cystitis (may follow radiation therapy); and chemotherapy agents such as cyclophosphamide (hemorrhagic cystitis).

Clinically, it affects females far more than males. Symptoms include frequency, urgency, dysuria, and suprapubic pain; systemic signs such as fever and malaise are uncommon. Predisposing factors include benign prostatic hypertrophy, bladder calculi, and cystocele.

Malakoplakia is a bladder inflammatory pattern associated with a defect in macro-phage function. The cause is unknown. Macrophages contain Michaelis-Gutmann bodies, laminated basophilic structures.

Urinary bladder tumors are most commonly due to transitional cell carcinoma. There is an increasing incidence of urinary bladder tumors; males are affected more than females, and peak incidence is age 40-60. Risk factors include:

•         Cigarette smoking and occupational exposure to azo dye production (transi-tional cell carcinoma) (both due to 2-naphthylamine)

•         Chronic bladder infection with Schistosoma haemotobium (squamous cell car-cinoma) (Africa including Egypt and the Middle East)

Bladder cancer usually presents with painless hematuria, but it may also cause dys-uria, urgency, frequency, hydronephrosis, and pyelonephritis.

Prognosis of bladder cancer depends on the tumor grade and stage. There is a high incidence of recurrence.

Precursors of invasive transitional cell carcinoma can arise from a flat or papil-lary lesion.

•         Carcinoma in situ (CIS) is a high-grade lesion with cytologic atypia in the full thickness of the epithelium. It is frequently multifocal. In 50-75% of untreated cases, it progresses to invasive cancer.

•         Papillary precursors to invasive carcinoma include papilloma ⇒ papillary urothelial neoplasia of low malignant potential ⇒ low-grade urothelial carcinoma ⇒ high-grade urothelial carcinoma.

Other bladder tumors include papillomas, adenocarcinoma, and embryonal rhab-domyosarcoma.

Miscellaneous bladder conditions

•         Acquired diverticuli can complicate urinary tract outlet obstruction due to benign prostatic hyperplasia or other causes.

•         Cystocele is the term used for prolapse of the bladder into the vagina. It is common in middle-aged to elderly women.

•         Cystitis cystica et glandularis causes formation of small cysts and glands in the bladder mucosa related to chronic inflammation. It is associated with an increased risk of adenocarcinoma.