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Urethra
Author: Nat Pernick, M.D. (see Authors page)
Last revised: 4 January 2011, last major update 2002
Copyright: (c) 2002-2010, PathologyOutlines.com, Inc.
Excludes prostatic urethra (see Prostate chapter)
Table of contents
Primary references
Inflammation, tumors-benign, carcinomas, clear cell carcinoma. melanoma
Primary references
AJCC Cancer Staging Manual (7th ed)
American Journal of Clinical Pathology (AJCP), Jan 1997 to Nov 2002 (no photos)
American Journal of Surgical Pathology (AJSP), Jan 1997 to Nov 2002
Archives of Pathology and Laboratory Medicine (Archives), January 1997 to Nov 2002
Human Pathology (Hum Path), Jan 1997 to Oct 2002
Modern Pathology (Mod Path), Jan 1997 to Nov 2002
Robbins Pathologic Basis of Disease (6th Ed)
Rosai, J: Ackerman’s Surgical Pathology (8th Ed); Mosby-Year Book, Inc., 1996
Please refer to these primary references for more detailed discussions and photographs
Urethra-normal
Males: consists of mucosa, submucosa, surrounding corpus spongiosum
Meatal and parameatal urethra lined by squamous epithelium; penile and bulbomembranous urethra lined by pseudostratified or stratified columnar epithelium; prostatic urethra lined by urothelium
Distal to prostate are scattered islands of stratified squamous epithelium and glands of Littre’
Females: epithelium supported by connective tissue, surrounded by longitudinal smooth muscle continuous with bladder
Urethra continuous with vaginal wall
Distal 2/3 lined by squamous epithelium, proximal 1/3 lined by urothelium
Skene’s glands are concentrated near meatus but found throughout its length
Periurethral glands lined by pseudostratified and stratified columnar epithelium
Urethra-inflammation
Urethritis: gonococcal or non-gonococcal
Associated with prostatitis and cystitis
Nephrogenic (mesonephric) adenoma
Metaplastic change, not neoplastic, common in urethra
Similar to lesions in bladder neck
Non-gonococal urethritis
E coli, Chlamydia trachomatis, Ureaplasma urealyticum
Part of Reiter syndrome (urethritis, conjunctivitis, arthritis)
Prolapse
May occur in childhood and simulate a neoplasm
Urethral tumors - benign
Caruncle
Resembles small raspberry protruding from external urethral meatus
Extremely painful
Bleeds easily, may become infected
Only in female urethra
Considered a reactive polypoid lesion
Often recurs, perhaps due to persistence of inciting factors
Treatment: excision
Micro: highly vascularized fibroblastic connective tissue with chronic inflammation, dilated blood vessels, hyperplastic epithelium
DD: carcinoma
Leiomyoma
Relatively common in women, rarely (<10 reported) in men
Case report in 48 year old man with quadriplegia, Archives 2000;124:302
Papillomas
May be viral
Urethral carcinomas
Rare, more common in women than men
Often elderly women around external meatus, often associated with urethral diverticula
In men, associated with chronic strictures
Presents with bleeding and dysuria
May be warty/papillary, often HPV+
Often ulcerated
Usually squamous cell
50% of tumors arising in urethra diverticula are adenocarcinoma or clear cell carcinoma
More aggressive than bladder cancers (5 year survival 41%); death in a few years from local growth
Metastases to lung, liver, bone
Treatment: radiation therapy, possibly surgery
Clear cell carcinoma
Usually women, mean age 58
Similar clinical presentation to other urethral carcinomas
No association with endometriosis
Case reports: 82 year old woman with urethral mass (Case of Week #194)
Gross: often (56%) arises within a urethral diverticulum
Micro: similar to clear cell adenocarcinoma of female genital tract; tubulocystic, papillary, and diffuse patterns; hobnail and flattened cells, cells with abundant clear cytoplasm; moderate to marked nuclear pleomorphism; frequent mitotic figures
DD: nephrogenic adenoma
Negative stains: PSA, PAP
Reference: Mod Path 1996;9:513
Melanoma
Adults, mean age 73
Usually involves distal urethra in men and women; less common in bladder
5 year survival ~ 20% (may die of unrelated causes), AJSP 2000;24:785
Treatment: total urethrectomy plus bilateral inguinal node dissection
Gross: polypoid, mean 2.6 cm
Micro: vertical growth phase often has prominent nodular component; also radial growth phase; abundant eosinophilic cytoplasm with large nuclei and prominent nucleoli; numerous mitoses; melanin pigment usually present, but often focal
DD: urothelial carcinoma, sarcomatoid carcinoma
Changes from AJCC 6th to 7th edition: For urothelial carcinoma of prostate, T1 is defined as tumors invading subepithelial connective tissue
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
Tis: Carcinoma in situ
T1: Tumor invades subepithelial connective tissue
T2: Tumor invades any of the following: corpus spongiosum, prostate or periurethral muscle
T3: Tumor invades any of the following: corpus cavernosum, beyond prostatic capsule, anterior vagina or bladder neck
T4: Tumor invades other adjacent organs
Urothelial (transitional) carcinoma of prostate
Tis pu: Carcinoma in situ, involvement of prostatic urethra
Tis pd: Carcinoma in situ, involvement of prostatic ducts
T1: Tumor invades urethral subepithelial connective tissue
T2: Tumor invades any of the following: corpus spongiosum, prostatic stroma or periurethral muscle
T3: Ttumor invades any of the following: corpus cavernosum, beyond prostatic capsule, bladder neck (extraprostatic extension)
T4: Tumor invades other adjacent organs (invasion of bladder)
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
N2: Metastasis in a single lymph node more than 2 cm in greatest dimension, or in multiple nodes
Distant Metastasis (M)
M0: No distant metastasis
M1: Distant metastasis
Stage grouping
Stage 0a: Ta N0 M0
Stage 0is: T1s N0 M0 or Tis pu N0 M0 or Tis pd N0 M0
Stage I: T1 N0 M0
Stage II: T2 N0 M0
Stage III: T1-T2 N1 M0, T3 N0-N1 M0
Stage IV: T4 or N2 or M1
End of Urethra chapter