Scalp Arteriovenous malformation (AVM) is a rare vascular anomaly that accounts for 8.1% of all AVM presentations, with only case reports and series reported in the literature.1 It is characterized by pathological subcutaneous tangles of enlarged and dilated scalp arteries and veins that communicate directly and have a nidus in the subgaleal plane.2, 3, 4 The aberrant connections between these scalp arteries and veins result in high-flow arteriovenous (AV) shunting and the pathological recruitment of collateral vessels.4 The first accurate description of scalp AVM was provided by Hunter in 1757.5 The other widely used name for scalp AVM is “cirsoid” (from the Greek kirsos, meaning “varix,” or varicose vein) because of the serpentine appearance and characteristic variceal dilatation of the draining veins.6,7 Other names used to describe scalp AVMs include aneurysm cirsoide, cirsoid aneurysm, aneurysma serpentinum, aneurysm racemosum, plexiform angioma, and AV fistula.7,8 Scalp AVM is generally not life-threatening, and the most common presenting symptoms are pulsatile mass, debilitating throbbing headache, tinnitus, and disfigurement.1,2 The involvement of the intracranial arterial supply and/or veinous drainage in scalp AVM cases has been reported in the literature, making them even more complicated.9

To date, appropriate management of scalp AVMs remains unclear and risky. The results can be poor, as there is no agreed-upon management algorithm for scalp AVMs, given the overwhelming rarity of reported cases and the lack of prospective evidence-based data.10, 11, 12 Cases of scalp AVMs can be challenging, and careful consideration and study of the anatomy, size, and arterial supply are required before implementing a definitive management plan.2 Historically, surgical excision (SE) has been the predominant approach for the management of scalp AVMs.1,2 Recent advancements in endovascular techniques and the introduction of novel embolic materials have led to the increasing adoption of endovascular embolization (EE) as a minimally invasive strategy for scalp AVM treatment.1,11,13 Various approaches have been described for accessing AVM, including femoral transarterial and femoral transvenous catheterization of the feeding arteries or draining veins. In addition, in cases where the feeding arteries are tortuous and difficult to access, a direct puncture (DP) approach for embolization is considered an effective alternative.1,13 Embolic materials have a wide variety of options including coils, onyx, glue, radiopaque gel foam, isobutyl-2-cyanoacrylate, n-butyl cyanoacrylate, polyvinyl alcohol particles, and thrombin. They can be used alone or in combination with each other, on single or multiple routes.6,13

The use of either SE or EE as a single management approach for scalp AVMs has been associated with various complications, with EE having a significantly higher complication rate than SE. A systematic review by Sofela et al. included 143 and 54 scalp AVM cases that were managed using SE and EE, respectively. SE complications included scalp necrosis (5.7%), wound infection (2.1%), hemorrhage (1.4%), and sepsis (0.7%). In comparison, the complications of EE included transient scalp pain in 34.6%, residual mass in 13.5%, painless skin inflammation in 3.8%, scalp necrosis in 1.9%, and multiple aneurysms in 1.9%.2 However, when employed before the SE, the EE value became clearer. Sofela et al. also included 35 scalp AVM cases managed using the combined method of EE and SE, and none of these cases developed any complications.1 In such circumstances, EE usually minimizes the size of the AVM and increases the safety of SE.1,11

The systematic review by Sofela et al. included the highest number of scalp AVM cases in the literature and concluded that the combined method yielded excellent results without any complications. However, as previously mentioned, only a small number of cases were managed using this combined method.1 As many articles on scalp AVMs treated using the combined method of preoperative EE and SE have been published since the last systematic review, further studies on the efficacy and outcomes of such an approach as a treatment for scalp AVM are needed to either support or deny previous observations.1 In this systematic review, we aimed to evaluate the efficacy of the combined approach of preoperative EE and SE for scalp AVMs, and present an illustrative case report.

A 58-year-old female, with a medical history of diabetes mellitus, hypertension, and dyslipidemia presented to our clinic with a scalp mass that was first noted 2 years prior to presentation. The mass was progressively enlarging, tender, pulsatile, and associated with unilateral tinnitus. The patient had no history of any trauma. Her systemic review was unremarkable; she reported no family history of similar conditions and was not on any anti-thrombotic medications. Upon examination, she was alert and oriented toward the person, place, and time. The neurological examination results were unremarkable. A palpable tender pulsatile mass was observed in the left temporal region. Ultrasound showed a subcutaneous vascular lesion with dimensions of 1.4 × 1.9 × 0.5 cm.

Further evaluation with computed tomography (CT) angiography identified a left superficial temporal artery scalp AVM with multiple feeders and drainage into the external jugular vein with no intracranial extension (Figure 1). Given these findings, a decision regarding a combined therapeutic approach involving both preoperative EE and SE was made after a multidisciplinary consultation. One week after diagnosis, the patient was admitted to the hospital. She initially underwent preoperative EE, achieving an 80–90% reduction in AVM vascularity using detachable coils and a liquid embolic agent (Phil 25%) without any complications (Figure 1). On the third day post-EE, the patient was placed in the operating room for the SE of the lesion. A small reverse question mark incision was made in the left temporal region to expose the mass (Figure 2). During the procedure, the nidus was identified and the draining veins were marked with vascular loops. Subsequently, the feeding arteries were identified, coagulated, and severed under Doppler ultrasound guidance. The nidus was meticulously dissected from the superficial temporal fascia and the associated draining veins were suture-ligated and excised (Figure 2). The SE was completed with minimal blood loss (20 cc) and no complications.

Postoperative CT angiography revealed a complete AVM excision without residual lesions (Figure 1). The patient recovered uneventfully and was discharged on postoperative day 3. Histopathological evaluation confirmed the diagnosis of scalp AVM (Figure 3). The patient was examined at the clinic after two days. There were no signs of skin necrosis and the wound healed well. Five months postoperatively, a follow-up CT angiogram showed no evidence of lesion recurrence, and the patient remained symptom-free.