Primary urethral cancer

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

Epidemiology

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

Clinical presentation

• urethral bleeding
• palpable urethral mass
• obstructive voiding symptoms
• perineal pain

Pathology

The histologic types are transitional cell carcinoma in 55%, squamous cell carcinoma in 21.5%, and adenocarcinoma in 16.4%. In rare instances, sarcoma or melanoma can also occur.

Risk factors include:

• urethral stricture
• history of sexually transmitted diseases
• urethritis
• human papillomavirus exposure
• bladder cancer

Location

In males, 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, stratifed squamous epithelium) is involved in 46% of the cases. The posterior segment (proximal third, stratifed squamous epithelium) is responsible for the remainder of cases.

Staging

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.

Radiographic features

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

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

Treatment and prognosis

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