Sclerosing Retroperitoneal Fibrosis.

This refers to an uncommon cause of ureteral narrowing or obstruction characterized by a fibrous proliferative inflammatory process encasing the retroperitoneal structures and causing

hydronephrosis.[3] The disorder occurs in middle to late age. In some cases, specific causes can be identified, such as drugs (ergot derivatives, b-adrenergic blockers), adjacent

inflammatory conditions (vasculitis, diverticulitis, Crohn disease), or malignant disease (lymphomas, urinary tract carcinomas). However, 70% of cases have no obvious cause and are

considered primary or idiopathic (Ormond disease). Several cases have been reported with similar fibrotic changes in other sites (referred to as mediastinal fibrosis, sclerosing cholangitis,

and Riedel fibrosing thyroiditis), suggesting that the disorder is systemic in distribution but preferentially involves the retroperitoneum. Thus, an autoimmune reaction, sometimes triggered

by drugs, has been proposed.

On microscopic examination, the inflammatory fibrosis is marked by a prominent inflammatory infiltrate of lymphocytes, often with germinal centers, plasma cells, and eosinophils.

Sometimes, foci of fat necrosis and granulomatous inflammation are seen in and about the fibrosis.

Urinary Bladder

Diseases of the bladder, particularly inflammation (cystitis), constitute an important source of clinical signs and symptoms. Usually, however, these disorders are more disabling than

lethal. Cystitis is particularly common in young women of reproductive age and in older age groups of both sexes. Tumors of the bladder are an important source of both morbidity and

mortality.

CONGENITAL ANOMALIES

Diverticula.

A bladder or vesical diverticulum consists of a pouchlike eversion or evagination of the bladder wall. Diverticula may arise as congenital defects but more commonly are acquired lesions

from persistent urethral obstruction.

Congenital diverticula may be due to a focal failure of development of the normal musculature or to some urinary tract obstruction during fetal development. Acquired diverticula are most

often seen with prostatic enlargement (hyperplasia or neoplasia), producing obstruction to urine outflow and marked muscle thickening of the bladder wall. The increased intravesical

pressure causes outpouching of the bladder wall and the formation of diverticula. They are frequently multiple and have narrow necks located between the interweaving hypertrophied

muscle bundles. In both the congenital and acquired forms, the diverticulum usually consists of a round to ovoid, saclike pouch that varies from less than 1 cm to 5 to 10 cm in diameter.

Although most diverticula are small and asymptomatic, they may be clinically significant, as they constitute sites of urinary stasis and predispose to infection and the formation of bladder

calculi. They may also predispose to vesicoureteral reflux as a result of impingement on the ureter. Rarely, carcinomas may arise in bladder diverticuli. When invasive cancers arise in

diverticula, they tend to be more advanced in stage as a result of diverticula's thin or absent muscle wall.

Exstrophy.

Exstrophy of the bladder implies the presence of a developmental failure in the anterior wall of the abdomen and in the bladder, so that the bladder either communicates directly through a

large defect with the surface of the body or lies as an opened sac ( Fig. 21-3 ). These lesions are amenable to surgical correction, and long-term survival is possible. The exposed bladder

mucosa may undergo colonic glandular metaplasia and is subject to the development of infections that often spread to upper levels of the urinary system. In the course of persistent chronic

infections, the mucosa often becomes converted into an ulcerated surface of granulation tissue, and the preserved marginal epithelium becomes transformed into a stratified squamous type.

There is an increased tendency toward the development of carcinoma later in life, mostly adenocarcinoma of the colon.[4] Patients also have an increased risk of adenocarcinoma arising

from the bladder remnant.

Date: 2016-04-22; view: 1501