Urethral caruncle: clinicopathologic features of 41 cases.

Urethral caruncle is a benign polypoid mass of the urethral meatus in primarily postmenopausal women. Although a conclusive association with malignancy, urologic disorder, or systemic disease has not been established, often the lesion carries a challenging clinical differential diagnosis that includes malignancy. Conversely, unexpected malignancy is identified in some cases resembling caruncle clinically. We examined clinical and histopathologic characteristics in 41 patients. Medical records were assessed for presentation, clinical diagnosis, associated urothelial carcinoma, radiation treatment, tobacco use, immunologic/urologic disorder, and treatment strategy/outcome. Average patient age was 68 years (range, 28-87 years). Presenting symptoms were pain (37%), hematuria (27%), and dysuria (20%), in contrast to asymptomatic (32%). Clinical diagnosis favored malignancy in 10% of cases. Concurrent or subsequent urothelial carcinoma was present for 5 patients (12%), although none developed urethral carcinoma. Histologic features included mixed hyperplastic urothelial and squamous lining, overlying a variably fibrotic, edematous, inflamed, and vascular stroma. Invaginations of urothelium extending into the stroma were common (68%), showing rounded nests with cystic or glandular luminal spaces, similar to urethritis cystica/glandularis, without intestinal metaplasia. Two lesions included an organizing thrombus, 1 with intravascular papillary endothelial hyperplasia. Twenty patients were treated with topical medications without resolution. Three lesions recurred (7%) after excision. A subset of patients had history of smoking or previous pelvic irradiation. Urethral caruncle is an uncommon lesion that may clinically mimic benign and malignant conditions. Awareness of the spectrum of clinical and histologic differential diagnoses is important in dealing with this unusual disease.