Primary urethral cancer

Last revised by Joshua Yap on 11 May 2023

Primary urethral cancer, in most cases a urethral carcinoma, is a rare urological malignancy. It can be divided into female urethral cancer and male urethral cancer.

It has an incidence of 4.3 per million for males and 1.5 per million for females. It usually manifests in the 5th decade of life.

Risk factors include:

  • urethral bleeding

  • palpable urethral mass

  • obstructive voiding symptoms

  • perineal pain

The histologic types are transitional cell carcinoma in 55%, squamous cell carcinoma in 22%, and adenocarcinoma in 16%. In rare instances, sarcoma or melanoma can also occur. Transitional cell carcinoma occurs most commonly in the prostatic urethra whereas squamous cell carcinoma occurs in the remaining urethral segments 5.

In males, the bulbomembranous urethra is the most involved in 60% of the cases, followed by the penile urethra (30%) and prostatic urethra (10%). 

In females, the anterior segment (distal two thirds, stratified squamous epithelium) is involved in 46% of the cases. The posterior segment (proximal third, stratified squamous epithelium) is responsible for the remainder of cases. 

TNM staging for female urethral cancer is identical to that for male urethral cancer. See the relevant article on staging of urethral cancer.

In males, it can spread by direct extension into adjacent structures, such as the corpus spongiosum and the periurethral tissues. In females, it usually spreads to the bladder neck, the vagina or the vulva.

Lymphatic metastases usually spread to superficial and deep inguinal nodes and pelvic nodes. Hematogenous spread is uncommon.

Multiple radiographic investigations are useful, including retrograde cystourethrography, voiding cystourethrogram, contrast-enhanced CT, and MRI.

MRI is most sensitive and specific for local extension.

  • T1: low signal mass, difficult to differentiate from urethra

  • T2: high signal mass 

  • T1 C+ (Gd): variable enhancement

The optimal treatment for urethral cancer is not well defined. Multimodal therapy with surgery, radiation therapy and chemotherapy is advocated, especially in advanced disease.

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Cases and figures

  • Case 1: urethral cancer (female)
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  • Case 2: urethral cancer (female)
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