Lower Urinary Tract and Male Genital System

• Components of the Lower Urinary Tract and Male Genital System

  • Renal pelves
  • Ureters
  • Urinary bladder
  • Urethra
• Urothelium


  A special form of transitional epithelium lining the renal pelvis, ureters, urinary bladder, and urethra
• Urothelium composition


  • Composed of five to six layers of cells with oval nuclei, often with linear nuclear grooves, and a surface layer consisting of large, flattened "umbrella cells" with abundant cytoplasm
• Lamina propria


  Tissue beneath the urothelium containing wisps of smooth muscle forming a discontinuous muscularis mucosa
• Bladder musculature undergoes hypertrophy


  If urine flow is obstructed and intravesical pressures rise
• Chapter Contents of the Lower Urinary Tract

  • Ureters
  • Congenital Anomalies
  • Tumors and Tumor-Like Lesions
  • Obstructive Lesions
  • Sclerosing Retroperitoneal Fibrosis
  • Urinary Bladder
  • Congenital Anomalies
  • Inflammation
  • Acute and Chronic Cystitis
  • Special Forms of Cystitis
  • Metaplastic Lesions
  • Neoplasms
  • Urothelial Neoplasms
  • Other Epithelial Bladder Tumors
  • Mesenchymal Tumors
  • Secondary Tumors
  • Obstruction
  • Urethra
  • Inflammation
  • Tumors and Tumor-Like Lesions
• Chapter Contents of the Male Genital Tract

  • Penis
  • Congenital Anomalies
  • Inflammation
  • Tumors
  • Testis and Epididymis
  • Congenital Anomalies
  • Regressive Changes
  • Atrophy and Decreased Fertility
  • Inflammation and Infections
  • Vascular Disorders
  • Spermatic Cord and Paratesticular Tumors
  • Testicular Tumors
  • Germ Cell Tumors
  • Tumors of Sex Cord-Gonadal Stroma
  • Lesions of Tunica Vaginalis
  • Prostate
  • Inflammation
  • Benign Enlargement
  • Neoplasms
• The ureters lie throughout their course in a retroperitoneal position
• Relaxation of pelvic support in middle-aged and older women

  Leads to prolapse (descent) of the uterus, pulling with it the floor of the bladder
• Enlargement of the prostate in males


  Constitutes an important cause of urinary tract obstruction
• Retroperitoneal tumors or fibrosis may entrap and obstruct the ureters
• In middle-aged and older women, relaxation of pelvic support leads to prolapse (descent) of the uterus, pulling with it the floor of the bladder
• In males, the seminal vesicles and prostate have similar close relationships, being situated just posterior and inferior to the neck of the bladder
• Subsequent sections discuss the major pathologic lesions of the ureters, urinary bladder, and urethra
• Strictures


  • May be congenital or acquired
• Tumors

  • Urothelial carcinomas arising in ureters
  • Rarely, benign tumors or fibroepithelial polyps
• Blood clots


  • Massive hematuria from renal calculi, tumors, or papillary necrosis
• Neurogenic


  • Interruption of the neural pathways to the bladder
• Extrinsic


  • Pregnancy
  • Physiologic relaxation of smooth muscle or pressure on ureters at pelvic brim from enlarging fundus
• Periureteral inflammation


  • Salpingitis, diverticulitis, peritonitis, sclerosing retroperitoneal fibrosis
• Endometriosis


  • With pelvic lesions associated with scarring
• Tumors


  • Cancers of the rectum, bladder, prostate, ovaries, uterus, cervix; lymphomas, sarcomas
• URETERS

  • Congenital Anomalies
  • Tumors and Tumor-Like Lesions
  • Obstructive Lesions
  • Sclerosing Retroperitoneal Fibrosis
• Congenital anomalies of the ureters are found in about 2% to 3% of all autopsies. Certain anomalies may lead to obstruction of the flow of urine and cause clinical disease
• Ureteropelvic junction (UPJ) obstruction is the most common cause of hydronephrosis in infants and children. It is more common in women in adults and is often unilateral
• Primary tumors of the ureter are rare. Benign tumors are generally of mesenchymal origin. The majority of malignant tumors are urothelial carcinomas
• Intrinsic and extrinsic lesions may obstruct the ureters and give rise to hydroureter, hydronephrosis, and pyelonephritis
• Sclerosing Retroperitoneal Fibrosis is characterized by a fibrotic proliferative inflammatory process that encases retroperitoneal structures and causes hydronephrosis. It is more common in males and may be related to IgG4-related disease
• Bladder adenocarcinomas mostly present as adenocarcinomas, accounting for a small minority of bladder cancers overall
• Inflammation

  • Acute and Chronic Cystitis
  • Bacterial pyelonephritis is frequently preceded by infection of the urinary bladder, with retrograde spread of microorganisms
• Types of bladder cancers

  • Adenocarcinomas
• Adenocarcinomas account for only a small minority of bladder cancers overall (0.1% to 0.3%), but constitute 20% to 40% of bladder adenocarcinomas
• Bacterial pyelonephritis


  Frequently preceded by infection of the urinary bladder, with retrograde spread of microorganisms into the kidneys and their collecting systems
• Predisposing factors for cystitis

  • Bladder calculi
  • Urinary obstruction
  • Diabetes mellitus
  • Instrumentation
  • Immune deficiency
• Common etiologic agents of cystitis

  • Coliforms: Escherichia coli
  • Proteus
  • Klebsiella
  • Enterobacter
• Causes of cystitis

  • Tuberculous cystitis
  • Candida albicans
  • Cryptococcal agents
  • Schistosomiasis (Schistosoma haematobium)
  • Viruses (e.g., adenovirus)
  • Chlamydia
  • Mycoplasma
• Gas-forming bacteria (such as Clostridium perfringens) result in emphysematous cystitis (gas-filled vesicles in the bladder wall)
• Exstrophy of the bladder is a developmental failure in the anterior wall of the abdomen and the bladder
• Urachal anomalies may create a fistulous urinary tract connection between the bladder and umbilicus
• Most cases of cystitis produce nonspecific acute or chronic inflammation of the bladder