A urethral caruncle is a benign fleshy outgrowth at the urethral meatus. It is the most common lesion of the female urethra, occurring primarily in postmenopausal women.
The terms urethral caruncle, urethral prolapse, and urethral polyp are sometimes used interchangeably. Technically, urethral prolapse refers to mucosa that is circumferentially everted at the meatus, whereas urethral caruncle refers to eversion of only a portion of the distal urethra, often at the posterior edge.
The pathogenesis of urethral caruncles is not well understood. A distal segment of the urethral mucosa, most commonly the posterior lip of the urethral meatus, prolapses to form the caruncle. Estrogen deficiency after menopause results in atrophy of the uroepithelium, which appears to be a predisposing factor. Chronic inflammation of the exposed, prolapsed urethral mucosa may lead to enlargement, bleeding, and necrosis.
Histologically, urethral caruncles contain a core of blood vessels and loose connective tissue covered by hyperplastic urothelial and squamous epithelium [1,2]. Chronic irritation of the prolapsed segment of mucosa results in a dense inflammatory infiltrate. The stromal component may be associated with variable degrees of edema, vascularity, red blood cell extravasation, and fibrosis; dilated blood vessels may contain organizing thrombus . Urethral caruncles are subclassified as granulomatous, papillomatous, or angiomatous .
Patient presentation — Most patients are postmenopausal, with occasional occurrences in premenopausal women and prepubertal girls [3,5-7]. Affected males have been described in single case reports [5,8].