Page 714 - Textbook of Pathology, 6th Edition

698 common abnormalities are haematuria, pain, fever and mucous glands in the urethral mucosa. The female urethra is
hypertension. The tumour rapidly spreads via blood, shorter and runs from the bladder parallel with the anterior
especially to lungs. wall of the vagina. The mucous membrane in female urethra
The prognosis of the tumour with combination therapy is lined throughout by columnar epithelium except near the
of nephrectomy, post-operative irradiation and chemo- bladder where the epithelium is transitional. The other layers
therapy, has improved considerably and the 5-year survival and mucous glands are similar to those in male urethra.
now is 80-90%.
CONGENITAL ANOMALIES
Secondary Tumours
Leukaemic infiltration of the kidneys is a common finding, Vesicoureteric reflux is the most common anomaly described
particularly in chronic myeloid leukaemia. Kidney is a already on page 682. A few others are considered below.
common site for blood-borne metastases from different DOUBLE URETER. This is a condition in which the entire
primary sites, chiefly from cancers of the lungs, breast and ureter or only the upper part is duplicated. Double ureter is
stomach. invariably associated with a double renal pelvis, one in the
upper part and the other in the lower part of the kidney. If
LOWER URINARY TRACT double ureter affects the entire length, then there are two
separate openings into the bladder on one side but more
commonly they are joined in the intravesical portion and
NORMAL STRUCTURE
open by a single ureteric orifice.
The lower urinary tract consists of ureters, urinary bladder and URETEROCELE. Ureterocele is cystic dilatation of the
urethra.
terminal part of the ureter which lies within the bladder wall.
URETERS are tubular structures, 30 cm in length and half a The cystic dilatation lies beneath the bladder mucosa and
centimeter in diameter, and extend from the renal pelvis can be visualised by cystoscopy.
(pelvi-ureteric junction) to the urinary bladder (vesico- ECTOPIA VESICAE (EXSTROPHY). This is a rare condition
ureteric junction). Normally they enter obliquely into the owing to congenital developmental deficiency of anterior
bladder, so that ureter is compressed during micturition, thus wall of the bladder and is associated with splitting of the
preventing vesico-ureteric reflux. Ureters lie retroperitoneally overlying anterior abdominal wall. This results in exposed
throughout their course.
interior of the bladder. There may be prolapse of the posterior
SECTION III
Histologically, ureter has an outer fibrous investing layer wall of the bladder through the defect in the anterior bladder
which overlies a thick muscular layer and is lined internally and abdominal wall. The condition in males is often
by transitional epithelium or urothelium similar to the lining associated with epispadias in which the urethra opens on the
of the renal pelvis above and bladder below. dorsal aspect of penis. If the defect is not properly repaired,
the exposed bladder mucosa gets infected repeatedly and
URINARY BLADDER lies extraperitoneally and the
peritoneum is reflected on its superior surface. Besides may undergo squamous metaplasia with subsequent
increased tendency to develop carcinoma of the bladder.
superior surface (or dome), the bladder has posterior surface
(or base) and two lateral surfaces. The trigone is at the base of URACHAL ABNORMALITIES. Rarely, there may be
the bladder and continues as blader neck. Normally, the persistence of the urachus in which urine passes from the
capacity of bladder is about 400 to 500 ml without over- bladder to the umbilicus. More often, part of urachus remains
Systemic Pathology
distension. Micturition is partly a reflex and partly a patent which may be the umbilical end, bladder end, or
voluntary act under the control of sympathetic and central portion. Persistence of central portion gives rise to
parasympathetic innervation. urachal cyst lined by transitional or squamous epithelium.
Histologically, the greater part of the bladder wall is made Adenocarcinoma may develop in urachal cyst.
up of muscular layer (detrusor muscle) having 3 coats—
internal, middle and external. The trigone muscle is derived INFLAMMATIONS
from the prolongation of the longitudinal muscle layer of
each ureter. The inner layer of bladder consists of urothelium Urinary tract infection (UTI) is common, especially in females
6-7 layers in thickness. The superficial epithelial layer is made and has been described already along with its morphologic
of larger cells in the form of a row and have abundant consequences (page 681). Inflammation of the tissues of lower
eosinphilic cytoplasm; these cells are called umbrella cells. urinary tract (ureteritis, cystitis and urethritis) are considered
here.
URETHRA runs from the bladder up to the external meatus.
The male urethra consists of 3 parts—prostatic, membranous Ureteritis
and penile. It is lined in the prostatic part by urothelium but
elsewhere by stratified columnar epithelium except near its Infection of the ureter is almost always secondary to pyelitis
orifice where the epithelium is stratified squamous. The above, or cystitis below. Ureteritis is usually mild but
urethral mucosa rests on highly vascular submucosa and repeated and longstanding infection may give rise to chronic
outer layer of striated muscle. There are numerous small ureteritis.