Urethral Caruncle

Practice Essentials

Urethral caruncles are benign, distal urethral lesions that are most commonly found in postmenopausal women, although rare cases have been reported in girls, and rarer cases of urethral caruncle has been described in males.^{[1, 2]} {ref233-INVALID REFERENCE} Additionally, urethral caruncles have been reported to occur rarely in premenopausal women and may enlarge during pregnancy. Urethral polyps are the pediatric equivalent of urethral caruncles and manifest in a similar fashion. Urethral caruncles resemble various urethral lesions, including carcinoma. The differential diagnoses of urethral caruncle include the following:

• Urethral diverticulum
• Urethral prolapse
• Urethral cancer^[3]
• Periurethral gland abscesses

Most urethral caruncles are readily diagnosed on physical exam alone, and can be treated conservatively with warm sitz baths and vaginal estrogen replacement. Surgical intervention may be indicated for patients with larger symptomatic lesions (eg, those causing urinary retention^[4] ) and for those with uncertain diagnoses.^[5] Possible indications for excisional biopsy include the following:

• Induration
• Failure to respond to conservative therapy
• Atypical appearance
• Growth over time
• Patient request

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Problem

Urethral caruncles, which often originate from the posterior lip of the urethra, may be described as fleshy outgrowths of distal urethral mucosa. They are usually small but can grow to 1 cm or more in diameter.

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Relevant Anatomy

The female urethra is a tubular structure 3-4 cm in length. It is normally lined by nonkeratinized stratified squamous epithelium distally and transitional epithelium proximally. Outer layers have a complex network of smooth muscle fibers and vascular structures. The female urethra and surrounding vaginal and vulvovestibular tissue are rich in estrogen receptors.

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Pathophysiology

The first step in the development of a urethral caruncle is likely distal, focal urethral prolapse caused by urogenital atrophy due to estrogen deficiency, now known as genitourinary syndrome of menopause. Chronic irritation, where the urethral mucosa is exposed, contributes to the growth, hemorrhage, and necrosis of the lesion.

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Epidemiology

Urethral caruncles are common in elderly postmenopausal women but may rarely develop in girls or premenopausal or perimenopausal women.^{[6, 2]} Premenopausal women may develop relative estrogen deficiency due to exogenous oral contraceptives, postpartum state, or during breastfeeding. Isolated case reports describe urethral caruncles in males.^{[7, 8]}

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Prognosis

The prognosis is excellent if pathology confirms urethral caruncle as the diagnosis.

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History

Most urethral caruncles are asymptomatic and are incidentally noted on pelvic examination; however, some may be painful and others may be associated with dysuria. Many individuals with a urethral caruncle present with bleeding or, more commonly, after noticing blood on undergarments or with wiping; this may be mistaken for vaginal bleeding.^[9]  

Urethral caruncles are unlikely to explain voiding or storage symptoms in women. In fact, a comparison of lower urinary tract symptoms and urodynamic factors in incontinent women with and without caruncles found no differences.^[10]  Isolated case reports of urinary retention from urethral caruncle do exist, however.^{[11, 4]}

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Physical Examination

On examination, caruncles most often appear clinically as a pink or reddish exophytic lesion at the urethral meatus (see the image below); in rare cases, they are purple or black secondary to thrombosis. Some caruncular lesions may resemble urethral carcinoma.

Urethral caruncles usually protrude posteriorly (at the 6 o'clock position).

View Image

Photographs show the preoperative (a) and postoperative (b) appearance of a urethral caruncle in a 9-year-old girl. Courtesy of Journal of Medical Cas....

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Laboratory Studies

Obtain a urinalysis to rule out urinary tract infection when pain, discomfort, or dysuria is present or when an operative intervention is planned.

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Diagnostic Procedures

A urethral caruncle is obvious on physical examination, and biopsy is unnecessary in the vast majority of cases.

Cystoscopy can be performed, either in the office or at the time of excision, to rule out more serious pathologies or when the origin of hematuria is uncertain. Cystoscopy is not necessary when the diagnosis is obvious, hematuria is absent, and no surgical intervention is planned.

Sonography may be helpful in distinguishing urethral caruncle from other solid masses. On ultrasound, urethral caruncles are hypoechoic/isoechoic and rich in blood flow signal.^[24]  Hyperechoic spots, cystic echo areas, and macrocalcifications may be evident.^[25]

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Histologic Findings

Microscopically, a urethral caruncle resembles a bed of granulation tissue covered by either squamous or transitional epithelium. Infolding of epithelium may create papillary architecture. Inflammatory infiltration is common (see image below).

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This image shows marked vascular engorgement and a polymorphous inflammatory infiltrate in the stroma. Surface epithelium is benign. Courtesy of GT Ma....

A pathology series of 41 patients demonstrated mixed hyperplastic urothelial or squamous lining.^[1] The stroma demonstrated fibrosis, edema, and/or inflammation. Immunohistochemistry for immunoglobulin G (IgG) and IgG4 has been shown in a subset of patients, suggesting a possible autoimmune factor in some patients.^[26]

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Approach Considerations

Conservative therapy (ie, warm sitz baths, topical estrogen creams, topical anti-inflammatory drugs) is appropriate in most patients. Surgical intervention should be reserved for patients with larger symptomatic lesions (eg, those causing urinary retention^[4] ), for those in whom conservative therapy fails to elicit a response, and for those with uncertain diagnoses.^[27]

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Medical Care

Most urethral caruncles can be treated conservatively with warm sitz baths and vaginal estrogen replacement. Topical anti-inflammatory drugs may also be useful. Unfortunately, data on the efficacy of conservative management are lacking in the literature. In fact, a review of current literature completed in 2020 was unable to find any published systematic studies on the conservative management of urethral caruncles.^[28]

Nevertheless, anecdotal experience indicates that vaginal estrogen replacement is effective for many cases. Patients may notice symptomatic improvement within 6 weeks, but maximal effect of vaginal estrogen therapy is in 3 to 6 months.

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Surgical Care

Reserve surgical intervention for patients with larger symptomatic lesions and for those with uncertain diagnoses. Tumors are found in approximately 2% of urethral caruncles.^[16]  Possible indications for excisional biopsy include the following:

• Induration
• Failure to respond to conservative therapy
• Atypical appearance
• Growth over time

Cystourethroscopy should be performed if surgical excision is undertaken, to exclude bladder and urethral abnormalities. Many urologists perform a cystoscopy in the office upon initial patient presentation to rule out other pathologies (eg, carcinoma, diverticulum, abscess).

Preoperative Details

Standard vaginal preparation and preoperative antibiotics are recommended.

Intraoperative Details

Excision is usually an outpatient operation and involves the following steps:

• Place a Foley catheter
• Use stay-sutures in the epithelium to prevent mucosal retraction and meatal stenosis
• Excise the lesion
• Oversew the edges with 3-0 or 4-0 absorbable sutures (chromic or polyglactin)

Park and Cho have described an alternative technique for removal of a urethral caruncle whereby the base of the caruncle is ligated, allowing it to slough off after 1-2 weeks.^[29] Their technique requires neither anesthesia nor analgesics.

Postoperative Details

Following surgical excision, ensure that the patient can void adequately. If the patient is unable to void postoperatively or the surgery involved extensive excision, a Foley catheter may be left in place for 1-2 days to allow for appropriate healing of the urethral mucosa.

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Complications

If the epithelium is not everted adequately with the stay-stitch, meatal retraction and stenosis may occur.

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Long-Term Monitoring

If the lesion is benign, no special follow-up is required. However, patients who developed caruncles secondary to genitourinary syndrome of menopause should remain on vaginal estrogen to prevent new occurrences.

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Medication Summary

Vaginal estrogen replacement may be considered to treat urogenital atrophy secondary to estrogen deficiency in postmenopausal women.

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Estradiol vaginal (Estradiol intravaginal, Estrace Vaginal, Estring)

• Dosing, Interactions, etc.

Clinical Context:  Doses and recommended treatment duration for specific products vary. Creams or vaginal inserts are typically administered once daily for 1-2 weeks, followed by a reduced dose and a maintenance dose of 2-3 times weekly.

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Class Summary

Use of intravaginal estrogens help to maintain female urogenital elasticity and treats vulvovaginal atrophy. Estrogens increase cervical secretions and increase uterine tone.

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