39 Urethra
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SUMMARY OF CHANGES
• The definitions of TNM and the Stage Grouping for this chapter have not changed from the Fifth Edition.
C68.0 Urethra
INTRODUCTION
Cancer of the urethra is a rare neoplasia that is found in both sexes but is more common in females. The cancer may be associated in males with chronic stric- ture disease and in females with urethral diverticula. Tumors of the urethra may be of primary origin from the urethral epithelium or ducts, or they may be asso- ciated with multifocal urothelial neoplasia. Histologically, these tumors may rep- resent the spectrum of epithelial neoplasms, including squamous, adenothelial, or urothelial (transitional cell) carcinoma. Prostatic urethral neoplasms arising from the prostatic urethral epithelium or from the periurethral portion of the prostatic ducts are considered urethral neoplasms as distinct from those arising elsewhere in the prostate (see Chapter 34).
ANATOMY
Primary Site. The male urethra consists of mucosa, submucosal stroma, and the surrounding corpus spongiosum. Histologically, the meatal and parameatal urethra are lined with squamous cell epithelium, the penile and bulbomembra- nous urethra with pseudostratified or stratified columnar epithelium, and bul- bomembranithelium, and the prostatic urethra with transitional epithelium.
There are scattered islands of stratified squamous epithelium and glands of Littré liberally situated throughout the entire urethra distal to the prostate portion.
The epithelium of the female urethra is supported on subepithelial con- nective tissue. The periurethral glands of Skene are concentrated near the meatus but extend along the entire urethra. The urethra is surrounded by a longitudi- nal layer of smooth muscle continuous with the bladder. The urethra is con- tiguous to the vaginal wall. The distal two-thirds of the urethra is lined with squamous epithelium, the proximal one-third with transitional epithelium. The periurethral glands are lined with pseduostratified and stratified columnar epithelium.
Regional Lymph Nodes. The regional lymph nodes are:
Inguinal (superficial or deep)
Iliac (common, internal [hypogastric], obturator, external) Presacral
Sacral, NOS
Pelvic, NOS
The significance of regional lymph node metastasis in staging urethral cancer lies in the number and size, not in whether unilateral or bilateral.
Metastatic Sites. Distant spread is most commonly to lung, liver, or bone.
DEFINITIONS
Primary Tumor (T)(Male and Female)
TX Primary tumor cannot be assessed T0 No evidence of primary tumor
Ta Noninvasive papillary, polypoid, or verrucous carcinoma (Figures 39.1, 39.2)
Tis Carcinoma in situ
T1 Tumor invades subepithelial connective tissue (Figures 39.1, 39.3) T2 Tumor invades any of the following: corpus spongiosum, prostate,
periurethral muscle (Figures 39.1, 39.4, 39.5)
Urethral muscle
Urogenital diaphragm
FIGURE 39.1. Illustrated definitions of primary tumor (T) for Ta, T1, and T2 with depth of invasion ranging from the epithelium to the urogenital diaphragm.
Epithelium Ta
Corpus cavernosum
Subepithelial connective tissue Urethral muscle
Corpus spongiosum
FIGURE 39.2. Ta is defined as noninvasive papillary, polypoid, or verrucous
carcinoma.
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T1
FIGURE 39.3. T1 tumor invading subepithelial connective tissue.
T2
FIGURE 39.4. T2 tumor invades any of the following: corpus spongiosum, prostate, periurethral muscle (as illustrated).
Subepithelial connective tissue Urethral muscle Corpus spongiosum Corpus cavernosum
Prostate
T2 T2
FIGURE 39.5. Two views of T2 tumor in the male with invasion of the corpus spongiosum (left) and the prostate (right).
T3 Tumor invades any of the following: corpus cavernosum, beyond prosta- tic capsule, anterior vagina, bladder neck (Figures 39.6A–C)
T4 Tumor invades other adjacent organs (Figure 39.7) Urothelial (Transitional Cell) Carcinoma of the Prostate
Tis pu Carcinoma in situ, involvement of the prostatic urethra (Figure 39.8A)
Tis pd Carcinoma in situ, involvement of the prostatic ducts (Figure 39.8B)
T1 Tumor invades subepithelial connective tissue (Figures 39.8A, B)
A
T3
Urethra Vagina
B
FIGURE 39.6. A. Two views of T3 tumor in the male with invasion of the corpus
cavernosum (left) and prostatic capsule (right). B. T3 tumor in the female with
invasion of the anterior vagina.
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T3
Bladder neck
C
FIGURE 39.6. C. T3 tumor in the female with invasion of the bladder neck.
T4
Public bone
Vulva
FIGURE 39.7. T4 tumor in the female with invasion to other adjacent organs
(here, the pubic bone and vulva).
Epithelium Subepithelial connective tissue Periurethral muscle
A
Epithelium
Tis pd
Subepithelial connective tissue Prostatic stroma
Epithelium
T1
Subepithelial connective tissue Prostatic stroma
Epithelium
T2
Subepithelial connective tissue Prostatic stroma
B
FIGURE 39.8. A. The definition of Tis pu for urothelial (transitional cell)
carcinoma of the prostate (above dotted lines) is carcinoma in situ, involvement of
the prostatic urethra. T1 (below dotted lines) is defined as tumor invading
subepithelial connective tissue. B. Definitions of primary tumor (T) for urothelial
(transitional cell) carcinoma of the prostate for Tis pd, T1, and T2 with depth of
invasion ranging from the epithelium to the prostatic stroma.
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Urethral epithelium and subepithelial connective tissue Periurethral muscle
T2
Corpus spongiosum
Urethral epithelium and subepithelial connective tissue Periurethral muscle Corpus spongiosum
FIGURE 39.9. T2 for urothelial (transitional cell) carcinoma is defined as tumor invading any of the following: prostatic stroma, corpus spongiosum, periurethral muscle.
T2 Tumor invades any of the following: prostatic stroma, corpus spongio- sum, periurethral muscle (Figures 39.8B, 39.9)
T3 Tumor invades any of the following: corpus cavernosum, beyond pro- static capsule, bladder neck (extraprostatic extension) (Figure 39.10) T4 Tumor invades other adjacent organs (invasion of the bladder) (Figure
39.11)
Regional Lymph Nodes (N)
NX Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis
N1 Metastasis in a single lymph node 2 cm or less in greatest dimension (Figure 39.12)
N2 Metastasis in a single node more than 2 cm in greatest dimension, or in multiple nodes(Figures 39.13A, B)
Distant Metastasis (M)
MX Distant metastasis cannot be assessed M0 No distant metastasis
M1 Distant metastasis
Urethral epithelium and subepithelial connective tissue Periurethral muscle
Corpus spongiosum Corpus cavernosum capsule
Corpus cavernosum
FIGURE 39.10. Two views of T3 for urothelial (transitional cell) carcinoma.
Tumor invades any of the following: corpus cavernosum, as illustrated below dotted lines; beyond prostatic capsule; bladder neck (extraprostatic extension), as illustrated above dotted lines.
T4
Urinary bladder
FIGURE 39.11. T4
tumor invades other
adjacent organs
(invasion of the
bladder).
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£2 cm
£2 cm
N1 N1
FIGURE 39.12. N1 is defined as metastasis in a single lymph node 2 cm or less in greatest dimension.
>2 cm N2
