AVFs are vascular malformations characterized by the unusual shunt between arteries and veins, often enlarged; the hematic blood flow bypasses the capillary bed, so the local pressure is not downregulated. AVFs of the mandible can be acquired or congenital. The acquired forms are usually caused by a trauma involving the jaws. Congenital forms are present at birth and enlarge with physical growth; the growth is due to hormonal factors, vasomotor disturbances, or trauma. These DA-AVFs may be also a presentation of cerebrofacial arteriovenous metameric syndrome (CAMS).

Clinical and radiographic features of these lesions help in establishing a differential diagnosis. Despite this fact, signs and symptoms are often not univocal. A dental AVF is difficult to differentiate on the basis of their radiographic features alone and the misdiagnosis is easy.

These lesions are usually present at birth and enlarge with the growth of the child; there is generally no spontaneous regression. To our knowledge, only one case of regression after incisional biopsy and diagnostic angiography is reported [10].

A gradual increase in dimension is usually reported [11]. These lesions may also develop after penetrating trauma or blunt injury [12, 13].

The clinical characteristics of high-flow vascular malformations of the jaws are variable. Although infrequent, in cases with soft tissue involvement, typical symptoms like audible bruit, palpable thrill, pulsatile swelling, or the presence of vascular nevi and dilated veins may be found and must immediately grab the clinician's attention toward the possible presence of a vascular malformation.

The involvement of soft tissue seems to be more frequent in maxillary vascular malformations than in mandibular ones.

Other less specific clinical features are teeth loosening, dental misalignment, gingival bleeding, and neurosensory deficits [14]. Near-fatal hemorrhage is in some cases the first clinical sign of their presence [15].

The diagnosis is based on a combination of clinical and radiological features. There is a wide range of imaging techniques, including plain radiography, Doppler ultrasonography, computed tomography angiography (CTA), magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), and conventional angiography.

The first radiological diagnosis of jaw lesions usually relies on panoramic radiography.

On plain radiographs, vascular malformations appear cystlike lesions and unfortunately, there is often a lack of unique and distinctive signs.

Characteristics that should be considered suspicious for vascular malformations are: “soap bubble” or “honeycomb” aspect of the radiolucencies and resorption of roots.

Another characteristic sign is the presence of an expanded or double mandibular channel. This bony expansion is due to the intraosseous dilatation of the inferior alveolar artery and vein [16], and some authors also reported the evidence of an irregular widening of the inferior alveolar canal [17].

The lack of a discrete margin and of a sclerotic rim can help differentiate these lesions from dentigerous cysts.

The margins may also appear erosive, thus simulating a malignant lesion [18].

Roots resorption is another noticeable feature as reported by Darcey et al. [19] in case of slowly expanding lesions of the jaws. The roots resorptive pattern is usually focal and well-defined; on the contrary, in case of malignancies, the resorption pattern is often “ragged”; in this case, the pattern is particularly irregular and notched.

The cortical bone can be perforated over the expanded area, and the involvement of adjacent soft tissues may be present [3, 20].

Ultrasonography may be used to detect ecstatic vessels with high flow and low resistance Doppler signals but is not usually considered.

CT angiography is a valid option. It shows the vascular lesion and can help identify both the location and contributory feeding vessels.

MRI/MRA detect flow voids and can help distinguish between tumors and malformations.

Angiography is the gold standard to confirm the diagnosis and a fundamental tool to understand the architecture and the features of these lesions.

In our case, the radiographic and clinical appearance was comparable with that of a large odontogenic keratocyst or ameloblastoma.

Therapeutic ways include endovascular treatments (transarterial, transvenous, or percutaneous embolization), surgery, or a combination of those two.

Ligation of the external carotid artery has been previously described as a purely symptomatic treatment, before surgery, or as an emergency procedure.

Nowadays, there is little or no place for this procedure since it is well established that collateral circulation will rapidly be recruited from either the contralateral external carotid or vertebral systems. Moreover, the ligation of the external carotid artery may prevent any future embolization [21, 22].

Endovascular treatment is considered the first-line treatment for high-flow vascular malformations of the jaws. The literature shows a success rate of more than 70% [9].

A large variety of coils and embolic agents may be used for AVF embolization. The choice is subordinate to lesion’s site, size, and morphology.

Direct transosseous embolization may be evaluated for complex, high-flow lesions in which venous pouches are not accessible by transarterial or transvenous route [10, 23].

Embolization, however, is not a procedure free from complications; serious drawbacks like occlusion of pulmonary or cerebral vessels or recurrence of the vascular malformation should be considered.

Other reported problems of embolization include blindness, infection, tissue necrosis, severe pain, and poor cosmetic outcome.

To avoid revascularization, in particular in case of subtotal occlusion, surgery is usually indicated after endovascular embolization [24].

The timing of surgery remains a point of discussion. We believe that to avoid revascularization of the lesion, surgical enucleation should always be performed after embolization. The interval between the procedures should include between 48 h and 2 weeks. After the mere embolizations, bone remineralization should occur and according to Chhoeurn et al. should be completed within two years [25].

In our opinion, whenever feasible, the surgical removal of the embolized lesion should be performed since this is the only way to guarantee the complete reossification of the involved bone segment, thus providing a complete anatomical and functional recovery.

High-flow vascular lesions of the jaws are rare entities, but clinicians should always consider them in the differential diagnosis of osteolytic lesions of the jaws.

It is important to keep in mind the hemorrhagic potential of these lesions: a simple procedure, like an extraction, in the presence of an arteriovenous fistula may result in severe, potentially lethal, hemorrhage.

When detected, DSA and pre-operative embolization is a fundamental resource in the management of these lesions.