Urethral Carcinoma

Urethral cancer in male is extremely rare, comprising less than 1% of all urologic cancers. It is commoner in females than males [1]. Common predisposing factors for urethral carcinoma are chronic inflammation, infection or irritation of the urethra. Patients with a history of bladder cancer are also at an increase for urethral carcinoma [2]. They usually occur after the age of fifty years. The patients usually do not have characteristic symptoms or signs. Common symptoms they present with are a palpable perineal mass with or without obstructive voiding symptoms, serosanguinous discharge, urethral discharge, urethral fistula, periurethral abscess or perineal pain [1, 2]. Urethral tumors in male are categorized according to their location and the histologic characteristics of the cells that line the urethra. Most of the tumors (95%) are epithelial in origin. In males patients 60% of the tumors occur in the bulbomembranous urethra, 30% involve penile urethra and 10% occur in the prostatic urethra [2]. Squamous cell carcinoma is the most common type in male and account for 80% of the tumors, 15% Transitional cell carcinoma the second commonest and followed by adenocarcinoma or undifferentiated carcinoma in 5% of cases [3]. Commonest cell type involving prostatic urethra is transitional cell carcinoma (90%). Squamous cell carcinoma for only 10% of the tumors. The bulbomembranous and penile urethra are commonly involved by squamous cell carcinoma (80%, 90% respectively)and transitional cell type occur only in 10% of the time [3]. According to tumor prognosis and treatment male urethral carcinoma are categorized into two groups. Group 1 consists of tumors involving the external meatus, distal bulbous urethra up to the penoscrotal junction. This group present early with their signs and symptoms and diagnosed at a shorter period of time. Group 2 occurs in proximal urethra, membranous urethra and prostatic urethra and the patients present at a later stages of the disease and carries a poorer prognosis. Anterior urethral tumors are low grade and less extensive [4]. Male urethral cancer spread by direct extension to the adjacent structures and metastasize to regional lymph nodes. Hematogenous spread is uncommon, till the locally advance disease present or where the prostatic urethra is involved with primary transitional cell carcinoma [2]. Antegrade and retrograde urethrography is the imaging method of choice for assessing urethral abnormalities. It has limited role in assessing urethral carcinoma as the evaluation is limited to luminal pathology and does not assess tumor invasion into periurethral tissue [2]. Imaging of primary tumor by CT scan can help depicting local extension to surrounding structures and state of nodal metastasis. Tumors of distal urethra drain into superficial and deep inguinal lymph nodes the tumors from the proximal urethra drain to pelvic and para aortic nodes. However due to its poor contrast resolution CT scan has limited role in assessing the primary lesion extending into corporal bodies. MR imaging advantage over other imaging modalities due to its multiplanar imaging and superior contrast resolution in assessing the periurethral spread of the tumor. Normal membranous urethra can be seen on axial T2W images as a low signal intensity ring surrounding a high signal intensity epithelial surface [3]. Urethral tumors have signal intensity similar to or lower than the corpus on T1W and intermediate to low signal intensity on T2W sequences. With IV contrast the tumor usually show mild enhancement. Tumor extension into the tunica Albuginea or septa of corpus cavernosum can be readily demonstrated on T2W images [2, 3].