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10/4/2015
Hong Kong West Cluster Urology Symposium 2015:
Multi-disciplinary Approach on Bladder Cancer Management
Anatomy and Physiology of Bladder
Dr Wai-Kit Ma
Clinical Assistant Professor (Honorary)
Associate Consultant
University of Hong Kong Medical Centre
Queen Mary Hospital
Urinary bladder
• Pelvic organ
• Extraperitoneal
• When emptied – tetrahedral,
about the size and shape of
a pear
• When filled – oval, capacity
~500cc, goes up to lower
abdomen (suprapubic)
• The bladder has flexible muscular walls of
three layers thick.
• As urine fills the bladder, these walls expand;
they contract to expel urine.
Urinary bladder
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Dome
Anterior
Lateral (left & right)
Posterior
Trigone
Bladder neck
Parts of bladder
Dome
Right
lateral
Posterior
Left
lateral
Bladder
neck
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Documentation of bladder lesions
Documentation of bladder lesions
8 mm solitary superficial papillary growth at lower posterior wall
Bladder wall
• 4 layers:
• Innermost : Mucosa
(urothelium)
• Inner: Submucosa
(lamina propria)
• Middle : Detrusor muscle
(muscularis propria)
• Outer : Serosa
(adventitia)
Bladder wall - mucosa
Mucosa
• Basement membrane
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Transitional epithelium: lines the bladder, ureters, and urethra
Contains no blood or lymphatic vessels
Overlying GAG (glycosaminoglycan)
6 cell thick
Umbrella cells
Tight junction
Water tight
– Lies beneath the epithelial layer
– single layer of cells separating the epithelial layer from the lamina propria
– a sheet of extracellular material serving as a filtration barrier and
supporting structure for the mucosal layer
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Submucosa (lamina propria)
• Areolar connective tissue interlaced with the muscular coat
• Contains blood vessels, nerves, and in some regions, glands
• A tumor, which has spread to this layer (pT1), can metastasize to
the rest of the body via the lymphatics and blood vessels.
• Thickest at dome
(1.0-3.1 µm) and
thinnest at trigone
(0.5-1.6 µm)
Submucosa (lamina propria)
• May also contain adipose tissue, usually at the deep
aspect of LP contiguous with fat within muscularis
propria layer
Muscular layer (muscularis propria)
• Detrusor
– Inner longitudinal
– Middle circular (thick at
bladder neck : sphinteric
function)
– Outer longitudinal
• Arranged in meshwork
– Efficient emptying of the
spherical bladder
Muscularis propria
• Identification and status of involvement of MP is essential
in TURBT containing high grade or invasive carcinoma for
staging adequacy
Serous coat (serosa)
• A reflection of the peritoneum, which covers only the superior
surface and the upper part of the lateral surfaces
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Adventitia
Perivesical fat
• In areas on bladder where there is no serosa, the
connective tissue between organs merges
• Layer of fat surrounding bladder outside of
serosa/adventitia
• Present within this layer are blood vessels, nerves
TNM
Classification
Jewett-Strong
Marshall
Definition
Tis
0
Limited to mucosa, flat insitu
Ta
0
Limited to mucosa, papillary
T1
A
Lamina propria invaded
T2a
B1
< halfway through muscularis
T2b
B2
> halfway through muscularis
T3
C
Perivesical fat
T4a
C
Prostate, uterus or vagina
T4b
C
Pelvic wall or abdominal wall
N1-N3
D1
Pelvic lymph node(s) involved
M1
D2
Distant metastases
Regional lymph nodes
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Definite Statements of Non-invasion
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Non-infiltrating; non-invasive
No evidence of invasion
No extension into lamina propria
No stromal invasion
No extension into underlying supporting tissue
Negative lamina propria and superficial muscle
Negative muscle and (subepithelial) connective
tissue
• No infiltrative behavior/component
Bladder diverticulum
• Pouches in the bladder wall representing an
area of weakness through which the lining of
bladder is allowed to protrude
Urinary bladder - Urachus
• Anchors bladder to anterior
abdominal wall up to
umbilicus
• Paucity of muscle
• Lined by epithelium
• Lumen usually obliterated
Bladder diverticulum
• Congential/ acquired
• Asymptomatic vs incomplete emptying,
abdominal fullness, urinary tract infection
• Bladder scan post-void: mix-up with
significant residual urine
or retention
Urinary bladder - Urachus
• Significance:
• Patent lumen
– urachal cyst
→Infection / urinary fistula
• Mucosa
– Adenocarcinoma
• Resection en bloc with bladder during radical
cystectomy
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