Villous adenoma coexistent with focal well-differentiated adenocarcinoma of female urethral orifice: A case report and review of literature

BACKGROUND: Villous adenomas of the urinary tract are uncommon. They are morphologically similar to and difficult to differentiate from their counterpart in the colon. The histogenesis and malignant potential are uncertain. CASE SUMMARY: A 63-year-old woman was admitted to our hospital with a mass in the urethral orifice. Gross and microscopic pathological examination was suggestive of urethral villous adenoma with focal well-differentiated adenocarcinoma. The whole urethra and part of the bladder were excised. No further treatment was offered. Carcinoembryonic antigen, cytokeratin 7, cytokeratin 20, epithelial membrane antigen, and p53 protein were positive, and the ratio of Ki-67 was 60%. After follow-up at 11 mo, the patient was cured and had no recurrence. CONCLUSION: Immunohistochemistry is important for differential diagnosis of villous adenoma of the urinary system. Complete surgical resection of the urinary tract is curative.