Background
Urethral caruncles are benign, distal urethral lesions that are most commonly found in postmenopausal women. Recently, a case of urethral caruncle has also been described in a male.[1] Urethral caruncles resemble various urethral lesions, including carcinoma. The differential diagnoses of urethral caruncle include urethral diverticulum, urethral prolapse, urethral carcinoma, and periurethral gland abscesses.
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 1-2 cm in diameter.
Epidemiology
Frequency
Urethral caruncles are common in elderly postmenopausal women but are rare in premenopausal or perimenopausal women. Urethral prolapse is similar in appearance, but is circumferential while caruncles are focal. Urethral prolapse may occur in prepubescent or postmenopausal females, whereas caruncles are seen almost exclusively in the latter.
Etiology
Urethral caruncles may develop from several simultaneous processes, as discussed in the Pathophysiology section.
Pathophysiology
The first step in the development of a urethral caruncle is likely distal urethral prolapse caused by urogenital atrophy due to estrogen deficiency. Chronic irritation, where the urethral mucosa is exposed, contributes to the growth, hemorrhage, and necrosis of the lesion.
Cases of urethral melanoma,[2]tuberculosis,[3, 4] intestinal ectopia, lymphoma,[5, 6] and urethral leiomyoma[7] masquerading as urethral caruncle have been reported; however, reports of these associations are rare. Intraepithelial squamous cell carcinoma arising within a urethral caruncle has been reported in 2 patients.[8] Additionally, urethral caruncles have been reported to occur rarely in the premenopausal patient and may enlarge during pregnancy. Urethral polyps are the pediatric equivalent of urethral caruncles and manifest in a similar fashion.
Presentation
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, with the patient noticing blood on undergarments. 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.[9]
On examination, they most often appear clinically as a pink or reddish exophytic lesion at the urethral meatus; in rare cases, they are purple or black secondary to thrombosis. Some caruncular lesions may resemble urethral carcinoma.
Indications
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, for those in whom conservative therapy fails to elicit a response, and for those with uncertain diagnoses.
Relevant Anatomy
The female urethra is a 4- to 5-cm tubular structure. 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.
Contraindications
Surgical therapy should be reserved for women with larger symptomatic lesions and for women with uncertain diagnoses.
Karthikeyan K, Kaviarasan PK, Thappa DM. Urethral caruncle in a male: a case report. J Eur Acad Dermatol Venereol. Jan 2002;16(1):72-3. [Medline].
Nakamoto T, Inoue Y, Ueki T, Niimi N, Iwasaki Y. Primary amelanotic malignant melanoma of the female urethra. Int J Urol. Feb 2007;14(2):153-5. [Medline].
Indudhara R, Vaidyanathan S, Radotra BD. Urethral tuberculosis. Urol Int. 1992;48(4):436-8. [Medline].
Singh I, Hemal AK. Primary urethral tuberculosis masquerading as a urethral caruncle: a diagnostic curiosity!. Int Urol Nephrol. 2002;34(1):101-3. [Medline].
Khatib RA, Khalil AM, Tawil AN, Shamseddine AI, Kaspar HG, Suidan FJ. Non-Hodgkin's lymphoma presenting as a urethral caruncle. Gynecol Oncol. Sep 1993;50(3):389-93. [Medline].
Young RH, Oliva E, Garcia JA, Bhan AK, Clement PB. Urethral caruncle with atypical stromal cells simulating lymphoma or sarcoma--a distinctive pseudoneoplastic lesion of females. A report of six cases. Am J Surg Pathol. Oct 1996;20(10):1190-5. [Medline].
Saroha V, Dhingra KK, Gupta P, Khurana N. Urethral leiomyoma mimicking a caruncle. Taiwan J Obstet Gynecol. Dec 2010;49(4):523-4. [Medline].
Kaneko G, Nishimoto K, Ogata K, Uchida A. A case of intraepithelial squamous cell carcinoma arising from urethral caruncle. Can Urol Assoc J. Feb 2011;5(1):E14-6. [Medline]. [Full Text].
Ozkurkcugil C, Ozkan L, Tarcan T. The effect of asymptomatic urethral caruncle on micturition in women with urinary incontinence. Korean J Urol. Apr 2010;51(4):257-9. [Medline]. [Full Text].
Park DS, Cho TW. Simple solution for urethral caruncle. J Urol. Nov 2004;172(5 Pt 1):1884-5. [Medline].
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Petersen RO, Stein BS. Genitourinary Pathology. In: Practice of Urology. New York, NY: Norton Medical Books; 1993:48.
Rovner ES. Bladder and urethral diverticula. In: Wein AJ, Kavoussi LR, Novick AC, Partin AW, Peters CA. Campbell-Walsh Urology. Vol 3. 9th ed. Philadelphia, PA: WB Saunders Co; 2007:2361-72.
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