Urethral caruncle

A urethral caruncle is a benign fleshy outgrowth at the urethral meatus that occurs mainly at the posterior lip of the urethra.¹ It occurs almost exclusively in women, with a very small number of cases reported in men.²

How common is urethral caruncle? (Epidemiology)

Urethral caruncles are relatively uncommon overall, but are the most common benign tumour of the female urethra. They are most common in post-menopausal women, although can also occur rarely in premenopausal women and girls.³

The aetiology of urethral caruncles is not well understood. Given that they most frequently occur post-menopausally, oestrogen deficiency is thought to be involved. One theory is that low oestrogen levels lead to urogenital atrophy and lack of support of the surrounding smooth muscle, making the urethral epithelium more likely to prolapse. Chronic irritation, leading to inflammation, of the exposed urethra may then lead to caruncle formation.³ Other proposed mechanisms include urethral congestion, infection, trauma, and autoimmune factors.⁴⁵

Urethral caruncles are typically asymptomatic and are mostly reported as incidental findings during pelvic examination. Common symptoms include bleeding (which may be mistaken for vaginal bleeding), haematuria, pain, dysuria or a lump. Rarely, they can present with urinary retention.¹

Historia⁵

Often there are no symptoms but sometimes they are painful. There may be dysuria and occasionally they may bleed. Urethral caruncles do not appear to have a detrimental effect on micturition or continence.⁶ Urethral caruncles are an unusual cause of postmenopausal bleeding.

Examination

There is a soft smooth red fleshy lesion or red ring of urethral mucosa protruding through the urethral orifice. It may appear to be polypoid (sessile or pedunculated). They may (rarely) thrombose and turn purple or black. Urethral caruncles tend to be soft and may be tender whilst malignancy is usually firm and not tender.

The main differential diagnosis is urethral mucosal prolapse. The following conditions have been reported to present masquerading as a urethral caruncle:³

• Urethral polyp.

• Para-urethral (Skene's gland) cyst.

• Urethral diverticulum.

• Bartholin's cyst.

• Genital wart.

• Malignant melanoma of the urethra.⁷

• Carcinoma of the urethra.⁸⁹

• Bladder cancer (a papillary tumour may prolapse through the urethra).

• Urethral tuberculosis.

• Lymphoma.

• Urethral leiomyoma.¹⁰

• Intestinal ectopia.

If the diagnosis is clear there is no need for further investigation.

Other investigations may be required depending on the symptoms. For example, if dysuria is present, a midstream specimen of urine (MSU) should be sent for microscopy and culture to exclude urinary tract infection. If postmenopausal bleeding is present, investigations such as a pelvic ultrasound scan should be considered to rule out endometrial cancer (see postmenopausal bleeding). Only if there is uncertainty about diagnosis are cystoscopy and biopsy indicated.

If the diagnosis is clear and the lesion is asymptomatic then no further action is required. Management options include:

• In perimenopausal and postmenopausal women, topical oestrogens are useful.¹¹ Vaginal oestrogens should be trialled for 6 weeks, and continued at a maintenance dose if there has been improvement (and can be used indefinitely).³

• Warm salt baths and anti-inflammatory creams have been used, although some evidence suggests they lack efficacy.⁵

• If symptoms persist, caruncles can be removed using cauterisation, laser vaporisation, excision or even ligation. Cryotherapy or surgical excision may also be used.

• Surgical intervention is indicated only if the lesions are large or the diagnosis is uncertain.

  • Surgical techniques include simple excision, and ligation under general anaesthetic.³

If the diagnosis is correct, there is no associated mortality. Symptoms (if any) should subside with treatment.