An arteriovenous malformation (AVM) of the scalp is an abnormal fistulous connection between the feeding arteries and draining veins, without an intervening capillary bed within the subcutaneous layer.
Historically their unusual portly appearance led to various synonyms being coined for the entity viz., aneurysm cirsoide, aneurysm serpentinum, aneurysm racemosum, aneurysm by anastmoses, aneurysmal varix, arteriovenous fistula, plexiform angioma 1).
Its origin can be congenital or traumatic.
Congenital arteriovenous malformations (AVMs) of scalp are rare. They are usually not symptomatic at birth and are often misdiagnosed as haemangiomas. To date, only two cases of symptomatic neonatal scalp AVM have been reported in literature. Pathophysiology of congenital AVM is not completely understood but genetic and acquired causes are implicated. Diagnosis and management are often difficult and require multidisciplinary approach. Hussain et al. report a rare case of symptomatic congenital scalp AVM in a 10-day-old neonate who was successfully managed 5).
The clinical picture presents with complaints of increased scalp, scalp disfigurement, pain and neurological symptoms.
The treatment of sAVF is difficult, and many therapeutic approaches have been proposed. General approaches for the treatment of sAVF include ligation of the feeding arteries, surgical removal, electrothrombosis, embolization, and a combination of these approaches.
Although surgical excision is considered as definitive treatment for these lesions, troublesome intraoperative bleeding may pose a challenge.
Embolization as an alternative modality is gaining popularity.
Although most SAVMs can be operated by traditional method of excision, use of temporary clipping of feeding arteries (like Superficial temporal artery[STA], External carotid artery[ECA]) enables total excision of giant SAVMs with minimal blood loss for a definitive cure. This technique obviates the need for preoperative embolization 8).
Gangadharaswamy et al. present their experience in the surgical management of 3 cases with SAVMs using proximal feeding artery temporary occlusion followed by total surgical excision. The clinical presentations and radiological features of these cases are discussed in the article. Intraoperative blood loss was less than 150ml in all patients. Postoperative period was uneventful with no morbidity or mortality.
Intraoperative bleeding during surgical excision of scalp AVMs can be troublesome and challenging. To combat this, the authors advocate proximal feeding artery temporary clipping prior to surgical excision of the lesion. The external carotid artery was temporarily clipped in one case and superficial temporal artery in two patients.
Although most SAVMs can be operated by traditional method of excision, use of temporary clipping of feeding arteries (like Superficial temporal artery[STA], External carotid artery[ECA]) enables total excision of giant SAVMs with minimal blood loss for a definitive cure. This novel technique obviates the need for preoperative embolization 9).
Chowdhury et al., reported the experience of the surgical management of such lesions with a short review of the literature.
In this prospective study, 11 patients with scalp AVM and SVM, who underwent surgical excision of lesion in our hospital from 2006 to 2012, were included. All suspected high-flow AVM were investigated with the selective internal and external carotid digital subtraction angiogram (DSA) ± computed tomography (CT) scan of brain with CT angiogram or magnetic resonance imaging (MRI) of brain with MR angiogram, and all suspected low-flow vascular malformation (VM) was investigated with MRI of brain + MR angiogram. Eight were high-flow and three were low-flow VM.
All lesions were successfully excised. Scalp cosmetic aspects were acceptable in all cases. There was no major post-operative complication or recurrence till last follow-up.
With preoperative appropriate surgical planning, scalp AVM and SVM can be excised without major complication 10).
Eight patients with scalp vascular malformations admitted between 1997 and 2002.
All the patients were investigated with selective internal and external carotid angiography. Depending upon the origin of feeding arteries, the scalp vascular malformations were classified into two categories: Group I: the primary scalp arteriovenous malformations and Group II: secondary venous dilatations. Six patients belonged to Group I and two patients were in Group II.
Five patients belonging to Group I underwent successful excision of the arteriovenous malformation. There was no recurrence in this group. Of the two patients in Group II, one patient who had scalp vascular dilatation simulating a primary scalp vascular malformation underwent excision of the lesion. This patient developed severe postoperative brain edema and died.
Primary scalp vascular malformation can be excised safely. However, excision of secondary scalp venous dilatation without treatment of the intracranial component can be dangerous 11).
Muthukumar et al. treated 11 patients with cirsoid aneurysms surgically. All except one patient were males who were in the second and third decades of life. History of trauma was present in 6 patients. In one patient, the lesion had been present since birth. Occipital and frontal regions were the sites commonly involved. Superficial temporal, occipital and posterior auricular arteries were the most frequent feeding arteries. The size ranged from 3 cms to 12 cms. Following investigations were done: CT, MRI, MRA, angiography and Doppler studies.
Excision of the lesion was done in 8 patients and en bloc resection of the lesion with the scalp with reconstruction was done in the remaining three. One among the three patients who underwent en bloc resection had undergone prior surgery. None of the patients underwent preoperative endovascular treatment. One patient had undergone intralesional injection of sclerosing agents twice. Superficial scalp necrosis occurred in two patients but was treated successfully. All the patients except one had good cosmetic results and there was no recurrence during an average follow up of 18 months 12).
A retrospective review of 81 patients with extracranial arteriovenous malformation of the head and neck who presented to the Vascular Anomalies Program in Boston over the last 20 years. This study focused on the natural history and effectiveness of treatment. The male to female ratio was 1:1.5. Arteriovenous malformations occur in anatomic patterns. Sixty-nine percent occurred in the midface, 14 percent in the upper third of the face, and 17 percent in the lower third. The most common sites were cheek (31 percent), ear (16 percent), nose (11 percent), and forehead (10 percent). A vascular anomaly was apparent at birth in 59 percent of patients (82 percent in men, 44 percent in women). Ten percent of patients noted onset in childhood, 10 percent in adolescence, and 21 percent in adulthood. Eight patients first noted the malformation at puberty, and six others experienced exacerbation during puberty. Fifteen women noted appearance or expansion of the malformation during pregnancy. Bony involvement occurred in 22 patients, most commonly in the maxilla and mandible. In seven patients, the bone was the primary site; in 15 other patients, the bone was involved secondarily. Arteriovenous malformations were categorized according to Schobinger clinical staging: 27 percent in stage I (quiescence), 38 percent in stage II (expansion), and 38 percent in stage III (destruction). There was a single patient with stage IV malformation (decompensation). Stage I lesions remained stable for long periods. Expansion (stage II) was usually followed by pain, bleeding, and ulceration (stage III). Once present, these symptoms and signs inevitably progressed until the malformation was resected. Resection margins were best determined intraoperatively by the bleeding pattern of the incised tissue and by Doppler. Subtotal excision or proximal ligation frequently resulted in rapid progression of the arteriovenous malformation. The overall cure rate was 60 percent, defined as radiographic absence of arteriovenous malformation. Cure rate for small malformations was 69 percent with excision only and 62 percent for extensive malformations with combined embolization-resection. The cure rate was 75 percent for stage I, 67 percent for stage II, and 48 percent for stage III malformations. Outcome was not affected significantly by age at treatment, sex, Schobinger stage, or treatment method. Mean follow-up was 4.6 years 13).
Twenty-four patients with cirsoid aneurysms of the scalp. For nine patients (38%), the lesions were related to trauma. Each of the patients presented with a pulsatile scalp swelling with a bruit. No focal neurological deficits were noted in any of the patients. Scalp malformations in all patients were confirmed by selective internal and external carotid angiography, with no intracerebral component revealed in any of the patients. Twenty-one patients had the lesions surgically excised, with good results. The remaining three refused surgical intervention. Meticulous surgical technique, which includes removal of the pericranial component of the malformation, was paramount 14).
Ten patients with scalp arteriovenous fistulas associated with a large varix (cirsoid aneurysms) were treated with a combination of interventional neuroradiologic procedures. These procedures included transarterial embolization, transarterial embolization followed by surgical excision, and two new methods of treatment of cirsoid aneurysms: transvenous embolization and direct puncture of the fistula for embolization. The embolic materials included liquid adhesive agents, particulate agents, detachable balloons, and wire coils. The embolization was performed to lodge the embolic agents in the fistula or proximal draining vein, not just the feeding vessels. Surgery was performed in two cases to remove a small residual nidus of fistula that could not be completely treated with intravascular embolization. With the use of these forms of treatment, cures were obtained in seven patients, and clinical and angiographic improvement was achieved in three patients. No major morbidity, blood loss, or mortality occurred during the treatment of these patients. The follow-up period ranged from 1 month to 8 years 15).
A 42-year-old patient who presented with a progressive worsening of visual acuity in the right eye (lower quadrantanopia) and palpebral ptosis. Physical examination revealed a right exophthalmos and a right frontoparietal scalp soft swelling when the patient was in the supine position. Neurologic work-up showed a scalp AVM extending into the orbit and connected to an intraorbital cavernous angioma. The patient was treated with a frontotemporal craniotomy and decompression of the orbit.
In the rare case of intraorbital extension of a scalp AVM, neurologic symptoms may appear when the size of the vascular malformation increases with age. The aims of surgery should be decompression of the orbit and aesthetic preservation, rather than complete excision 16).
A 21-year-old man presented with a right-sided bruit and an enlarging palpable, pulsatile scalp mass. Magnetic resonance imaging demonstrated a 5-cm right sAVM and an azygos anterior cerebral artery (ACA) feeding a 2-cm parafalcine vascular anomaly, as well as an unruptured 3-mm, flow-related, distal ACA aneurysm. sAVM feeders were catheterized and embolized with Onyx 18. During resection of the right frontal scalp lesion, dissection below the pericranium was developed to expose the low-flow extracranial sAVM. A supratrochlear arterial feeder and the vascular nidus were coagulated, but radical resection was avoided to prevent scalp necrosis. An anterior right frontal parasagittal craniotomy and dural opening were performed. A developmental anomaly of the right superior frontal gyrus was noted, and a dense vascular network within the anterior parafalcine fold was excised and coagulated. The distal ACA aneurysm was cauterized and wrapped to preserve the parent artery. The patient made an excellent recovery without neurologic deficits.
A review of the literature demonstrated a variety of endovascular and open surgical treatments with limited consensus on standard care. While sAVMs have been described in the literature, the combination of the diverse conditions seen in this case is unique 17).
Worm et al, present a case of giant scalp AVMs and its management, followed by a brief literature review on the subject. The diagnosis of scalp AVMs is based on physical examination and confirmed by internal and external carotid angiography or computed tomographic angiography (CTA). Surgical excision is especially effective in scalp AVMs, and is the most frequently used treatment modality 18).
Massimi et al. report on the unusual case of a child harboring a complex intracranial AVM that initially presented as a small scalp mass. Actually, this young boy came to the authors' attention just for a small, soft, pulsatile, and reducible mass of the vertex that produced a circumscribed bone erosion. The presence of macrocranium and venous engorgement of the face, however, suggested the presence of an intracranial “mass.” The neuroimaging investigations pointed out a temporal AVM causing dilation of the intracranial sinuses and ectasia of the vein of the scalp; one of the veins was appreciable as a lump on the vertex 19).
A 35-year-old man presented with occipital subcutaneous pulsatile thrill. Senoglu et al. discussed and illustrated a rare sAVF, which was a high-flow sAVF fed by the occipital branch of the right ACE draining intraosseously into the SS. The case was treated by surgical origin ligation.
This case was unusual in the sense that it was apparently spontaneous, and the major venous drainage was through the bone into the SS. Arterial supply pattern of sAVF is very important in therapeutic decision-making. We suggest that surgical origin ligation for sAVF be considered if the case has 1 feeding artery 20).
Craniofacial cirsoid aneurysm: 2-stage treatment 21).
A 21-year-old female consulted in 1998 complaining of right tinnitus and a pulsating mass in the retroauricular region. The initial angiogram revealed an AVM in the right temporo-parietal subcutaneous space with feeders from the STA, an occipital artery, a posterior auricular artery, and a middle meningeal artery (MMA). Three years later, she complained of enlargement of the lesion, increased tinnitus, and alopecia. Repeat angiographic study revealed the presence of a nidus and the appearance of new feeders from a contralateral MMA and an ipsilateral middle cerebral artery; there was a de novo saccular aneurysm in the right STA. On the day preceding surgery, the left MMA was embolized to control intraoperative bleeding. The AVM was removed totally without any dermal complications.
This case suggests that scalp AVMs can become enlarged by capturing subcutaneous or intracranial feeders, and that the consequent hemodynamic stress may induce de novo aneurysms in scalp AVMs. Capillary endothelial cells were strongly immunostained for vascular endothelial growth factor 22).
Heilman et al. report a patient in whom a large traumatic cirsoid aneurysm of the scalp was eliminated using a combined neurosurgical and interventional neuroradiological approach. Transarterial embolization was utilized to reduce arterial blood supply to the fistula. Thrombogenic Gianturco spring coils were then introduced via direct percutaneous puncture of the aneurysm. The aneurysm thrombosed and the multiple tortuous scalp vessels disappeared. One month after embolization, a small area of skin necrosis over the aneurysm necessitated surgical excision of the lesion. The thrombosed aneurysm was easily resected with minimal blood loss. Percutaneous embolization with thrombogenic coils in this case was a safe and effective ablative technique 23).