Traumatic Pseudoaneurysm Arising From Proximal Facial Artery: A Case Report and Literature Review

Abstract

Pseudoaneurysms of facial artery usually arise from the distal part of the vessel. Only 4 cases were described in the literature involving the proximal part of facial artery. We present a case of a traumatic pseudoaneurysm involving the proximal part of facial artery. A 50-year-old man was referred to our department for a progressively growing submandibular mass. He was injured by a sharp object during a car crash 30 days ago. After 3 weeks, the patient noted the appearance of a subcutaneous mass in the left submandibular area. Physical examination revealed a freely movable, painful, and pulsatile swelling. Ultrasound and computerized tomography scan showed a nodular lesion in the left submandibular area in continuity with the facial artery. The diagnosis of pseudoaneurysm of facial artery was suspected. The patient was treated by surgery. The pseudoaneurysm was resected with ligation of the proximal and distal ends of the facial artery.

Introduction

A pseudoaneurysm is a rare delayed vascular complication subsequent to head and neck injuries. Pseudoaneurysms of the extracranial arterial system are extremely uncommon. The most affected branches are the superficial temporal artery, internal maxillary artery, and distal part of the facial artery, usually where they pass over the bone and become more vulnerable to blunt or penetrating trauma. ¹

We present a case of a post-traumatic pseudoaneurysm involving the proximal part of facial artery in the submandibular area. To the best of our knowledge, this is the fifth case in the literature.

Case Report

A 50-year-old man was referred to our department for a progressively growing submandibular mass. He was injured by a sharp object during a car crash 30 days ago. Local bleeding was controlled by pressure. The wound was sutured under local anesthesia. After 3 weeks, the patient noted the appearance of a small subcutaneous mass in the left submandibular area. Rapid enlargement of the swelling was noted during the next week. Physical examination revealed a freely movable, painful, and pulsatile swelling in the left submandibular region measuring 50 mm. Blood examinations, including coagulation profile, platelet count, and prothrombin time, showed no abnormalities. Ultrasound showed a hypoechoic, heterogeneous, and well-limited mass measuring 38 mm (Figure 1). Computerized tomography (CT) scan of the neck with contrast was carried out. It revealed a circumscribed nodular lesion in the left submandibular area measuring 29 × 20 mm, part of it showing intensive accumulation of the contrast and the other part filled with thrombotic masses. This lesion was in continuity with the facial artery with visible continuity of the contrast inside the vessel and inside the lesion. The diagnosis of pseudoaneurysm of facial artery was suspected (Figures 2 and 3). The patient was treated by surgery under general anesthesia. During surgery, we noted a large hematoma, which was evacuated. After dissection, a pseudoaneurysm was identified in the facial artery as shown by CT scan. The pseudoaneurysm was resected with ligation of the proximal and distal ends of the facial artery. The patient was discharged 72 hours postoperatively. Histopathologic examination of the pseudoaneurysmal capsule showed that it was hematoma, with extravasation in the vessel wall lumen, inflammatory infiltration, and hyalinization confirming the diagnosis of pseudoaneurysm. At 6 months postoperatively, the patient showed no evidence of recurrence.

Figure 1.

Ultrasound of the neck: a hypoechoic, heterogeneous, and well-limited mass.

Figure 2.

Axial computerized tomography (CT) scan of the neck with iodine injection: circumscribed nodular lesion in the left submandibular area (white arrow) measuring 29 × 20 mm.

Figure 3.

Axial (A) and sagittal (B) computerized tomography (CT) scan of the neck with iodine injection: intensive accumulation of the contrast (white arrow) in continuity with the facial artery.

Discussion

Pseudoaneurysm or false aneurysm is caused by partial or tangential laceration of arteries. Some pseudoaneurysms involve the 2 innermost tissue layers, tunica intima and tunica media, and these retard typical clinical manifestations such as bleeding and hematoma. Others involving the outermost layer, the tunica adventitia, may express early clinical manifestation. ² Our patient noticed the appearance of submandibular swelling 3 weeks after the trauma. The extravasations of blood from the cut area form an aneurysmal sac composed of the nearby connective tissues, and the bleeding continues until the hematoma and arterial pressure become the same. A thrombus, which remains in continuity with the feeding vessel, is formed and then gradually liquefies. Organization of the thrombus results in a fibrous capsule lined by a pseudointimal layer. Once the center of the thrombus liquefies, the aneurysmal sac and the artery communicate to form a pulsatile mass. Then, as the pseudoaneurysm gradually expands due to the arterial pressure, it continues to enlarge or ruptures. ³ Pseudoaneurysms of the branches of the external carotid artery are rare and usually result of blunt or penetrating trauma with partial transection of the vessel wall. The rarity of pseudoaneurysms of the branches of the external carotid artery is thought to be secondary to the small size of most of the vessels, which makes complete transection much more likely than partial laceration. In addition, the deeper, larger vessels are protected by more soft tissue. Pseudoaneurysms of facial artery usually arise from the distal part of the vessel where it is vulnerable to trauma as it crosses the mandible. Only 4 cases were described in the literature involving the proximal part of facial artery. One case was caused after a gunshot wound to the neck. ³ Two other cases occurred secondary to surgical intervention (alveoplasty ⁴ and open reduction and rigid internal fixation for condylar fracture. ⁵ ) For the last patient, no etiology was identified. ⁶ The pseudoaneurysm became obvious after a period of 2 weeks to 3 years. The treatment varies by angiographic embolization in 2 cases, ^3,4 intralesional sclerotherapy in one case ⁵ and surgery under general anesthesia in one case. ⁶ Despite the different techniques, the pseudoaneurysm was treated successfully in all cases. The postoperative course was uneventful except for the patient treated by sclerotherapy who developed a mild tissue irritation and subsequent abscess formation in the submandibular space which was managed with incision and drainage. ⁵ To the best of our knowledge, this is the fifth reported case involving the proximal part of the facial artery and the second due to penetrating injury. Computed tomography and duplex Doppler ultrasonography are useful for diagnosis. ⁷ Choi et al found that 3-dimensional CT is helpful in the diagnosis of a pseudoaneurysm by revealing a round lesion with vascular enhancement. ⁸ Computerized tomography angiography confirms the diagnosis. However, the final diagnosis of pseudoaneurysm is made by the pathologist, who can microscopically distinguish true from false aneurysm, depending on the layers of the vessel wall involved ⁶ as it was for our patient. Treatment for aneurysm is mandatory to avoid the risk of spontaneous expansion and rupture. ⁶ The historical treatment is surgery especially when the lesion is located superficially and directly accessible. ⁶ Dediol et al ⁶ advocated the surgical management as a treatment of choice for pseudoaneurysm with signs of local infection. In our case, the pseudoaneurysm did not show signs of infection. Pseudoaneurysm can be treated by ligating the blood vessel, which is the cause of the lesion, and then can be possibly removed surgically. There are no consequences to tissue perfusion with ligation of the facial artery, and the risk of perioperative complications is minimal. ⁶ However, the surgical removal of pseudoaneurysm has fundamental limitations such as external scar formation or excessive bleeding during the surgical exploration. On the other side, advances in interventional radiology have allowed successful treatment of the pseudoaneurysm using endovascular embolization, with excellent results. ³ Such treatment is less invasive and more elective than traditional surgical techniques and is particularly useful for aneurysms for which surgical accessibility is difficult. ³ Embolization is also a safe and effective procedure that eliminates the risk of delayed bleeding and airway compromise and reduces the risks of pseudoaneurysm revascularization by collateral circulation. ⁹ However, neurological complication or soft tissue necrosis related to destruction of existing vascular lesion or reflux of embolization material had been reported. ¹⁰ Finally, this technique requires specific equipment and trained radiologist. These conditions were not available in our hospital or in other hospitals in the country at the time of the admission of our patient.