Villous adenoma of the urethra

Abstract

Villous adenoma of the genitourinary system is rarely encountered by the general urologist. Although commonly seen in a colorectal practice, this tumor has been infrequently described in the urethra or bladder. In the genitourinary tract, this tumor appears to have excellent survival when isolated; however, it does have an association with adenocarcinoma of the genitourinary or gastrointestinal tract. Here we present a case of villous adenoma of the urethra managed with a multidisciplinary approach, which led to discovery of invasive adenocarcinoma of the rectum.

Villous adenoma is commonly encountered in the colorectal practice but is rarely seen by the urologic surgeon. Fibroepithelial urethral polyps are more readily seen by the urologist; they are generally benign and can be treated with local resection/ablation to resolve irritative voiding symptoms. Other encountered benign urethral lesions include hemangiomas, leiomyomas, urethral diverticulum, and cowpers gland or skenes gland duct cysts. Due to the variability of presentation of suspicious lesions, most urologists opt for biopsy at the time of resection or fulguration to rule out underlying malignancy. Villous adenomas of the genitourinary tract have been reported, but generally in small case series or reviews of case reports.¹ They present similarly to other urethral lesions—with gross hematuria, dysuria, or irritative voiding symptoms—and a histopathologic diagnosis is usually needed.¹ Because reports of association with adenocarcinoma exist, most authors recommend full resection of the lesion and consideration of magnetic resonance imaging (MRI) and colonoscopy to rule out coexisting adenocarcinoma or malignancy.² The tumor is more commonly encountered at the bladder dome, trigone, and urachus if present.³

CASE REPORT

An 89-year-old white man presented to the urology clinic with increasing difficulty voiding, with a slowed stream, dysuria, and gross hematuria. He had a past urologic history significant for brachytherapy in 2004 and postbrachytherapy transurethral resection of the prostate in 2006, with an undetectable prostate-specific antigen level since treatment and minimal voiding complaints. He had no prior smoking history, had right nephrectomy previously for a nonfunctioning kidney, and had coronary artery disease. His physical exam revealed bilateral descended testes, no meatal stenosis, and no suprapubic fullness or tenderness. Urine culture was obtained in the clinic, and the patient was treated for urinary tract infection with culture-specific antibiotics for 7 days. His creatinine was at baseline.

He returned to the urology clinic a week later with improved dysuria but concern he was now passing small amounts of tissue and blood. There was clinical concern for sloughing of his urethra following brachytherapy vs underlying malignancy. Due to the patient’s gross hematuria, cystourethroscopy was performed, with biopsy of prostatic urethral tissue due to friability and erythema. The patient voided after the procedure with low postvoid residual and a catheter was deferred; medical therapy with tamsulosin and antibiotics was continued. Pathology of the tissue revealed predominantly villous adenoma with low-grade dysplasia; no high-grade dysplasia or invasive adenocarcinoma was identified. Although his symptoms had resolved, the patient was referred to colorectal surgery for a colonoscopy.

Colonoscopy by the colorectal surgery team revealed a large friable, fixed rectal mass; biopsy revealed tubulovillous adenoma with high-grade dysplasia. MRI of the pelvis revealed a 4.4 cm rectal tumor, which apparently involved the prostate and urethra (Figure 1). There was no discrete evidence of metastasis. At this time, the patient deferred definitive surgery, chemotherapy, or radiation and is pursuing palliative management.

Figure 1.

MRI demonstrating a locally advanced rectal mass with invasion into the prostate.

DISCUSSION

Villous adenoma of the urethra is a rarely encountered but important clinical entity to be recognized by the urologic surgeon. Our initial pathology demonstrated no malignancy; however, colonoscopy and MRI confirmed a locally advanced rectal mass. Villous adenoma of the urethra has been well associated with malignancy in previous case reports. Biopsy with MRI or colonoscopy is integral to ensuring a benign course of this lesion.³ Survival and overall prognosis appear to be excellent for patients with isolated villous adenoma of the urethra.⁴ Villous adenoma may need to be completely excised for best pathologic diagnosis. More aggressive treatment is indicated in cases with adenocarcinoma, and a multidisciplinary approach is often key.⁴ Our case demonstrates the importance of fully investigating these lesions with a goal of ruling out coexisting or invasive malignancy.