A Rare Case of Clitoral Arterial-Cavernous Shunt Presenting as Urethral Bleeding Treated with Embolization

Abstract

A 50-year-old woman presented with recurrent urethral bleeding. Initial dynamic computed tomography scans revealed abnormal enhancement in the corpus cavernosum of the clitoris, supplied by the right obturator artery. Subsequent magnetic resonance imaging indicated slight swelling of the corpus cavernosum without intricate vascular tangles suggestive of a nidus. A diagnosis of a clitoral arterial-cavernous shunt was suspected. Treatment involved successful transarterial embolization. Although clitoral arterial-cavernous shunts are uncommon, they can be effectively treated with targeted interventional approaches guided by accurate diagnostic imaging.

Introduction

The causes of abnormal bleeding observed in the female genital area are diverse and can stem from disease at any anatomical site, encompassing the lower genital tract (cervix, vagina, and vulva) or the upper genital tract (uterine corpus, fallopian tubes, and ovaries). Bleeding sources may also include non-gynecologic sites, such as the urethra, bladder, anus, or other bowel sites [1]. Here, we present a case of an arterial-cavernous shunt of the clitoris manifesting as urethral bleeding. Transarterial embolization proved highly effective in controlling the recurrent bleeding. To the best of our knowledge, a clitoral arterial-cavernous shunt is extremely rare. We hope that better awareness of this rare lesion will lead to improved patient care.

Case Report

A woman in her 50s presented to a gynecological outpatient clinic. Her symptom was genital bleeding during straining, such as during bowel movements, which had persisted for 1-2 years. She had no previous history of pelvic trauma or other significant medical history and did not regularly take oral medications. No genital tumors were observed on gynecological examination. However, bleeding was observed at the external urethral orifice. Therefore, the patient was referred to the Department of Urology. Cystoscopy revealed no abnormalities in the urethra or bladder.

Dynamic CT scans revealed no abnormal tumors in the abdominal or pelvic organs. However, partial early enhancement of the corpus cavernosum of the clitoris was observed during the arterial phase (Figure 1a), followed by homogeneous enhancement and slight clitoral swelling in the late phase. CTA indicated that the right obturator artery served as the feeding artery (Figure 1b). MRI confirmed slight swelling of the symmetrical corpus cavernosum of the clitoris with a homogeneous internal architecture (Figure 2). No aggregation of abnormal flow voids indicative of a nidus was observed on MRI. These imaging findings raised suspicion of an arterial-cavernous shunt involving the clitoris. Although the patient's vital signs remained stable, persistent urethral bleeding prompted referral to our department for intervention.

Figure 1.

Dynamic CT before interventional procedure.

a. The early phase of CE-CT shows abnormal enhancement in the cavernous sinus of the clitoris (white arrow).

b. CTA showing abnormal clitoral enhancement, which is thought to be supplied by the right obturator artery (white arrow).

CE-CT: contrast-enhanced CT

Figure 2.

Axial T2-weighted MR images show slight swelling of corpus cavernosum of the clitoris with homogenous inside architecture (white arrows).

The patient underwent an interventional procedure via the right femoral artery using a 4-F sheath. Initially, a left internal iliac arteriogram was performed to confirm the absence of abnormal staining. Abnormal staining was confirmed on the right internal iliac arteriogram (Figure 3a). For selective catheterization of an internal iliac arterial branch, a 1.9-F microcatheter (Progreatλ; Terumo Corporation, Tokyo, Japan) and a microwire (ASAHI Meister; ASAHI Intec, Aichi, Japan) were used. A selective angiogram of the right obturator artery demonstrated minute branches and a hypervascular lesion corresponding to the bilateral corpus cavernosum of the clitoris (Figure 3b). While direct catheterization of these minute branches was challenging, their occlusion representing the shunts was deemed crucial for the procedure (Figure 3c). Initially, microspheres were used to devascularize the small shunts and hypervascular lesions. Embolization with a 100-fold dilution of Embosphere 100-300 μm (Merit Medical Systems, South Jordan, Utah, USA) was performed. Following the injection of a total of 0.06 syringe vials, the abnormal staining nearly disappeared, although a few small feeding arteries persisted. Subsequently, embolization with n-BCA was performed. A mixture of n-BCA and iodized oil (Lipiodol; Guerbet Japan, Tokyo, Japan) in a 1:3 ratio was injected, leading to complete occlusion of the target artery (Figure 3d).

Figure 3.

a. The arterial phase of right internal iliac arteriogram shows abnormal stain (white arrow).

b. The selective arteriogram of right obturator artery shows hypervascular lesion corresponding to the clitoris.

c. Distal arteriogram of the right obturator artery shows tiny branches (white arrows) connected to the clitoris.

d. Post-embolization right internal iliac arteriogram shows complete disappearance of abnormal stain.

After the procedure, the patient experienced mild pain and itching around the clitoris for 2-3 days, and no other adverse events occurred. Within two weeks after the procedure, there were two episodes of very slight bleeding during straining; however, no further urethral bleeding has been noted since then. A contrast-enhanced CT scan performed three months after the procedure showed no abnormal enhancement in the clitoris. At the 1-year follow-up visit, the patient remained asymptomatic, with no recurrence of urethral bleeding.

Discussion

Here, we present a case of urethral bleeding caused by a clitoral arterial-cavernous shunt. Despite nonspecific symptoms, dynamic CT is valuable for detecting fast-flow vascular anomalies. Unlike an arteriovenous fistula, in which arteries and veins are directly connected [2], the arteries were directly connected to the clitoral cavernosum in our case. Interestingly, high-flow priapism in male patients appears to resemble our case in terms of angiographic findings [3]. Cavernous arterial fistulas following perineal trauma can lead to high-flow priapism; however, no traumatic episodes occurred in this instance. While penile priapism is well described, clitoral priapism in females is a rare condition characterized by prolonged painful erection of the clitoris [4, 5]. The most commonly reported etiologies of clitoral priapism are medications, including selective serotonin reuptake inhibitors or tricyclic antidepressants [4]. The patient in this case report did not experience clitoral pain and was not taking any such medications. The cause of the clitoral arterial-cavernous shunt in this case is considered idiopathic, and the urethral bleeding is presumed to have resulted from the hypervascular clitoral corpus cavernosum perforating the urethra. Although anatomically distinct, conjunctival hyperemia and intracranial hemorrhage associated with carotid-cavernous fistulas might be pathophysiologically similar to this case.

To the best of our knowledge, there are no reports in the literature of clitoral arterial-cavernous shunts similar to this case. Although not identical to arterial-cavernous shunts, AVMs are relevant in terms of hemodynamic consequences resulting from excessive arterial blood flow. Table 1 summarizes the reported cases of vulvar AVMs [6-10]. Most cases present as enlarged masses with heterogeneous MRI signal intensity [6, 9, 10]. These imaging findings differ from the homogeneous MRI signal observed in our case. In a case reported by Van der Woude et al. [8], the patient had experienced a traumatic episode in the pubic region 1 year earlier, and MRI showed an AVM of the left labium majus associated with vaginal bleeding. In that case, angiography showed a feeding artery originating from the superficial artery, corresponding to an arteriovenous fistula.

Table 1.

Summary of the Reported Cases of Valvular AVM.

Year	Authors	Age (years)	Clinical features	Treatment
2009	Revicky et al. [6]	26	Labium swelling and pain	Percutaneous sclerotherapy
2010	Brotherton et al. [7]	11	Vulvar bleeding	Embolization Surgical resection
2011	Van der Woude et al. [8]	13	Vulval pain, vaginal bleeding Trauma in the pubic region	Embolization
2015	Crosby et al. [9]	40	Vulval pain and mass	Percutaneous sclerotherapy
2018	Vienet-Legué et al. [10]	16	Swelling of labia majora, bleeding	Embolization Surgical resection

The symptoms of arterial-cavernous shunts may be nonspecific and vary depending on their location in the body. The urethral bleeding in our case was attributed to penetration of the clitoral arterial-cavernous shunt into the urethra. Although embolization of the clitoral arterial-cavernous shunt may cause clitoral dysfunction, we prioritized hemostasis above all else.

In conclusion, we report a case of a clitoral arterial-cavernous shunt successfully treated with transarterial embolization. While female genital tract bleeding can result from different conditions, such as gynecological tumors, vascular anomalies should also be considered as a potential cause.

Author Contributions

Drafting of the manuscript and literature review: MK, MS, KK. Case intervention and drafting of the manuscript: KK, TS. Critical revision of the manuscript: HO, MA, SK, KY. Final approval of the manuscript: all authors.

Conflicts of Interest

There are no conflicts of interest.

Informed consent

Informed consent for the use of medical records and submission of this case report was obtained from the patient.