INTRODUCTION — A urethral caruncle is a benign fleshy outgrowth of the posterior urethral meatus. It is the most common lesion of the female urethra and occurs primarily in postmenopausal women. The lesion is typically asymptomatic, although some women present with vaginal bleeding.
This topic will discuss the clinical presentation, diagnosis, and management of urethral caruncles in adults. Related topics on the evaluation of genital bleeding in women and urethral prolapse in children are presented separately:
●(See "Causes of female genital tract bleeding".)
●(See "Overview of vulvovaginal conditions in the prepubertal child".)
In this topic, when discussing study results, we will use the terms "woman/en" or "patient(s)" as they are used in the studies presented. However, we encourage the reader to consider the specific counseling and treatment needs of transgender and gender diverse individuals.
DEFINITION — The terms urethral caruncle, urethral prolapse, and urethral polyp represent three distinct lesions, although the terms are sometimes used interchangeably.
●Urethral caruncle – Urethral caruncle refers to eversion of only a portion of the distal urethra that often occurs at the posterior edge (picture 1) [1]. The caruncle is a small, fleshy mass that is soft, smooth or friable, and bright red to dark pink. These are generally single and sessile (picture 2), but they can also be pedunculated and grow to 1 to 2 cm. Caruncles typically occur in postmenopausal females and hypoestrogenism is the proposed mechanism. (See 'Pathogenesis and histology' below.)
●Urethral prolapse – Urethral prolapse refers to urethral mucosa that is circumferentially everted around the meatus [2]. The condition typically occurs in premenarcheal and postmenopausal females. The tissue can also be friable, ulcerated, and edematous. (See "Overview of vulvovaginal conditions in the prepubertal child", section on 'Urethral prolapse'.)
●Urethral polyp – Urethral polyps are more common in prepubertal males, but cases have been reported in prepubertal females [3-5]. In males, polyps mainly arise from the prostatic urethra. In females, urethral polyps can arise from any part of the urethra, are benign fibroepithelial polyps that are thought to be congenital, and often present as interlabial masses [5].
PATHOGENESIS AND HISTOLOGY — 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 [2]. Estrogen deficiency after menopause results in atrophy of the uroepithelium, which appears to be a predisposing factor, possibly by causing retraction of the postmenopausal vagina. Chronic inflammation of the exposed, prolapsed urethral mucosa may lead to enlargement, bleeding, and necrosis. Secondary infection can also occur.
Histologically, urethral caruncles contain a core of blood vessels and loose connective tissue covered by hyperplastic urothelial and squamous epithelium [6,7]. On ultrasound, caruncles are hypo- or isoechoic with regular borders and "abundant" blood flow signal [8]. 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 [9]. Urethral caruncles are subclassified as granulomatous, papillomatous, or angiomatous [10].
CLINICAL MANIFESTATIONS
●Incidental finding – Many females with urethral caruncles are asymptomatic, and the caruncle is identified as an incidental finding during genital examination. Most patients are postmenopausal, with occasional occurrences in premenopausal women and prepubertal girls [9,11-13]. Affected males have been described in single case reports [11,14]. In one study, an asymptomatic urethral caruncle was noted in 50 of 850 women (6 percent) who presented with urinary incontinence; all of the caruncles were <1 cm in diameter [15].
●Symptomatic females – Symptomatic females may present when they discover a lump at the urethral meatus or because of symptoms such as light bleeding, dysuria, pain, or rarely, obstruction to urine flow [2,16]. Microscopic hematuria and postmenopausal bleeding are other presentations. Bleeding may be associated with urination or it may be noted on toilet paper, feminine hygiene pads, or underclothes. In a review of 394 women presenting with caruncles and malignant urethral lesions, bleeding was the most common complaint [17]. Urinary obstruction was more common in women with a malignant urethral neoplasm than in those with a caruncle.
EVALUATION
●Lesion examination – The caruncle generally appears as a soft pink or red, sessile or pedunculated, polypoid lesion or growth that protrudes from a segment of the urethral meatus (picture 2 and picture 1). The exophytic mass is covered by epithelium and is usually <1 to 2 cm in greatest dimension. It may be friable, ulcerated, or hemorrhagic. Thrombosed lesions are deep blue, purple, or black.
●Urethral evaluation – The urethra should be palpated to assess for induration (suggestive of malignancy) or the presence of additional lesions not visible externally. Cystourethroscopy is indicated for further evaluation of the urethra if palpation reveals abnormalities. (See "Diagnostic cystourethroscopy (cystoscopy) for gynecologic conditions".)
●Urinalysis – Urinalysis should be obtained to look for hematuria and a urine culture is indicated in patients with hematuria or dysuria. Although a caruncle may cause microscopic or gross hematuria, females with hematuria are also evaluated for possible malignancy of the kidneys and urinary tract. This evaluation is discussed in detail separately. (See "Etiology and evaluation of hematuria in adults".)
●Biopsy – Biopsy of the urethral mass is not required for diagnosis, but excisional biopsy is indicated if the mass is irregular, firm, or has other characteristics suspicious for malignancy (eg, induration, local extension, inguinal adenopathy, increasing size, failure to respond to topical estrogen cream).
●Additional evaluation – As bleeding is a common symptom of urethral caruncles, it is important to consider the possibility of concurrent, potentially malignant causes of postmenopausal bleeding. The extent of evaluation depends on patient-specific factors (eg, associated symptoms, amount of bleeding, findings on pelvic examination, risk factors) and response to treatment of the caruncle. (See "Approach to the patient with postmenopausal uterine bleeding".)
DIAGNOSIS — The diagnosis of urethral caruncle can be based on characteristic findings on physical examination: a soft pink or red, sessile or pedunculated, exophytic mass protruding from the urethral meatus, usually <1 to 2 cm in size (picture 2 and picture 1). For patients in whom the diagnosis is uncertain, biopsy is performed under local anesthesia [2]. (See 'Evaluation' above.)
DIFFERENTIAL DIAGNOSIS — Caruncles can often be differentiated from other urethral lesions by their physical characteristics. If the diagnosis is uncertain or the lesion is not characteristic of urethral caruncle, biopsy is performed. In one of the largest series of urethral neoplasms, 9 of 394 excised urethral lesions (2.4 percent) thought to be benign caruncles were found to be malignant after histopathological examination [17]. (See 'Evaluation' above.)
The more common entities in the differential diagnosis of a distal urethral mass include [9,18-23]:
●Condylomata acuminata – Condylomata acuminata usually involve the vulva and/or vagina and are rarely isolated to the urethra. (See "Condylomata acuminata (anogenital warts) in adults: Epidemiology, pathogenesis, clinical features, and diagnosis".)
●Fibroepithelial polyp [3-5] – Polyps are mainly differentiated from urethral caruncles by age group. In females, polyps are typically congenital and present as an intralabial mass while caruncles are common in postmenopausal individuals. (See 'Definition' above.)
●Varices or hemangioma – Urethral varices at the meatus can mimic a caruncle. Varices may cause hematuria and may prolapse or thrombose ("urethral hemorrhoid") [24]. Compressing and releasing the varices should transiently disrupt blood flow, which helps to confirm the diagnosis of a vascular lesion. (See "Etiology and evaluation of hematuria in adults".)
●Leiomyoma [25] – While both urethral caruncle and leiomyoma are typically painless, a leiomyoma is firm and rubbery upon palpation. (See "Uterine fibroids (leiomyomas): Epidemiology, clinical features, diagnosis, and natural history", section on 'Clinical features'.)
●Malignancy – Tissue biopsy is required to diagnose malignancy.
•Transitional cell carcinoma [21]
•Sarcoma [26]
•Lymphoma [26,27]
•Melanoma [28,29]
•Squamous cell carcinoma [30]
•Urethral carcinoma [31]
•Metastatic disease
Rarely, urethral caruncle can mimic other conditions such as genital prolapse or ambiguous genitalia [32,33]. Extremely rare conditions that have been reported to mimic urethral caruncle include:
●Tuberculosis [34,35]
●Intestinal ectopia [36]
●Periurethral gland abscess [9]
●Inflammatory myofibroblastic tumor [9]
MANAGEMENT — Because of their low prevalence, there are no large studies or randomized trials evaluating treatment strategies for management of urethral caruncles [37].
Specialist referral — Most females with urethral caruncle are asymptomatic and don't require intervention. For those who are symptomatic, initial care can often be managed by nonspecialists. (See 'Symptomatic lesions' below.)
Some patients warrant specialty referral, typically to a female pelvic medicine specialist (urogynecologist) or urologist, depending on availability. We suggest routine specialty evaluation of patients in whom the diagnosis is not clear, who are symptomatic and do not respond to topical estrogen treatment or have persistent bleeding, or who have features suggestive of malignancy (eg, induration, increasing size, abnormal urethral examination). These patients can require excision or biopsy for definitive diagnosis and directed treatment. In my practice, the most common reason for referral is persistent bleeding.
Asymptomatic lesions — Asymptomatic females with caruncles that appear typical and benign do not require treatment [2].
Symptomatic lesions — Females with benign and typical-appearing caruncles who have symptoms (eg, bleeding, irritation, and dysuria) warrant treatment.
Initial approach — For first-line treatment of symptomatic patients, we suggest use of a topical estrogen cream for two to three months. The patient should apply a fingertip amount (ie, approximately 0.3 mg) of estrogen cream to the caruncle once daily for two weeks and then twice per week for two to three months. Low-dose vaginal estrogen has few risks, and patients using it do not require progestin treatment for endometrial protection [38,39]. (See "Genitourinary syndrome of menopause (vulvovaginal atrophy): Treatment", section on 'Patients with breast cancer'.)
Large or persistent lesions — In rare cases, if the caruncle is large and symptomatic or if symptoms do not resolve with topical estrogen therapy, we offer biopsy and surgical excision under local or regional anesthesia. Alternate treatment modalities include cryosurgery, laser therapy, or fulguration [2]. The optimal treatment is not known as comparative studies are lacking. In a retrospective review of 24 women who underwent surgical excision of urethral prolapse (not caruncle), three patients (12.5 percent) had visible recurrence, one of whom underwent repeat excision [40]. Complications included postoperative bleeding (six women, 25 percent), placement of a bladder catheter to tamponade urethral bleeding (one woman, 4 percent), and placement of a bladder catheter for temporary urinary retention (one woman, 4 percent). It is not known if postoperative topical estrogen treatment reduces the risk of recurrence.
Excision is performed by sharply excising the mass at the base. If the resulting mucosal defect is small, the edges can be reapproximated with a small (eg, 3-0 or 4-0) synthetic absorbable monofilament suture. If the defect is large, the edge of the urethral mucosa is everted onto the adjacent vaginal epithelium to minimize the risk of meatal stenosis, which is a potential complication of this procedure. A bladder catheter is usually left in place for several days in patients who require mobilization of the urethral mucosa.
Recurrent lesions — Symptomatic recurrence can be treated by excision or repeat use of topical estrogen. Maintenance therapy with twice weekly estrogen cream may prevent further recurrence.
OUTCOME — Data on treatment outcomes are sparse. A review of 41 female patients with an average age of 68 years (range 28 to 81) reported a 7 percent recurrence rate after surgical excision [9]. Of note, 20 subjects tried topical medications as first-line treatment without response and went on to excision. In this review, there were no malignancies or cytologic atypia found histologically in the surgical specimen.
A review of 46 girls aged 1.5 to 10 years treated for urethral prolapse (not caruncle) reported that medical treatment was successful in 11 of 15 girls (73 percent) treated with a topical antibiotic and steroid cream [41]. Repeated medical treatment was successful in two of four recurrences, while the other two patients went on to surgical excision. Of the 33 patients treated with surgical excision, 1 developed urethral stenosis, 1 developed symptoms of dysuria, and the remaining 31 patients had "very good" results.
SUMMARY AND RECOMMENDATIONS
●Description – Urethral caruncles are benign fleshy outgrowths at the urethral meatus, which are thought to be an eversion of the distal urethral urothelium. They are common lesions of the female urethra and occur primarily in postmenopausal individuals. (See 'Definition' above.)
●Etiology – Urethral caruncles are thought to result from prolapse of a distal segment of urethral mucosa. (See 'Pathogenesis and histology' above.)
●Clinical presentation – Many females with urethral caruncles are asymptomatic and the caruncle is noted as an incidental finding during genital examination. Symptomatic individuals may present when they discover a lump at the urethral meatus or because of symptoms such as light bleeding, dysuria, pain, or obstruction to urine flow. (See 'Clinical manifestations' above.)
●Initial evaluation – Initial evaluation consists of examination of the lesion and the urethra. Additional testing can include cystourethroscopy, biopsy, and evaluation for other causes of postmenopausal bleeding. (See 'Evaluation' above.)
●Diagnosis – The diagnosis of urethral caruncle is based on characteristic findings on physical examination. The caruncle appears as a soft pink or red, sessile or pedunculated lesion protruding from a segment of the urethral meatus, almost always from the posterior edge of the meatus (picture 2). Biopsy of the urethral mass is indicated if the diagnosis is uncertain. (See 'Diagnosis' above.)
●Differential diagnosis – Lesions that are considered in the differential diagnosis of urethral masses include condylomata acuminata, leiomyoma, fibroepithelial polyps, varices or hemangioma, and malignancy. (See 'Differential diagnosis' above.)
●Treatment
•Asymptomatic lesions – Treatment of asymptomatic urethral caruncles is unnecessary. (See 'Asymptomatic lesions' above.)
•Symptomatic lesions – For individuals with symptomatic urethral caruncles, we suggest use of a topical estrogen cream rather than excision (Grade 2C). Low-dose topical estrogen has few risks. (See 'Initial approach' above.)
•Persistent lesions – Biopsy and excision is indicated for large symptomatic urethral caruncles or when symptoms do not resolve with conservative therapy. (See 'Large or persistent lesions' above.)
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