Novel Onset of a Posttraumatic Superficial Temporal Artery Pseudoaneurysm

Less than 200 cases of posttraumatic superficial temporal artery pseudoaneurysm have been described in the literature. The majority of these cases result from blunt head trauma and are diagnosed an average of three weeks following the inciting traumatic event. In this case report, we describe a superficial temporal artery pseudoaneurysm that developed and was diagnosed the same day of a blunt head trauma in a 54-year-old white male. This is the earliest formation/diagnosis of post-traumatic superficial temporal artery pseudoaneurysm yet reported in the literature. This case report demonstrates that this diagnosis should be kept in the list of differential diagnoses for a post-traumatic soft tissue mass of the face, even immediately following the traumatic event. 1. Introduction Posttraumatic aneurysms do not commonly arise within the distribution of the facial artery, as the external carotid and its branches are protected in most locations by overlaying soft tissue. When they do occur, one of the most commonly affected vessels is the anterior branch of the superficial temporal artery (STA) because of its superficial course over the frontal bone, between the frontalis and temporalis muscles [1]. The majority (89%) of traumatic STA aneurysms are actually pseudoaneurysmal and form when partial transection of the arterial wall leads to extravasation of blood that gradually displaces surrounding soft tissues until they form a fibrous pseudocapsule enclosing a hematoma [2]. Fewer than 200 cases of traumatic STA pseudoaneurysm have been reported in the literature [2]. Given their potential for rupture and hemorrhage, it is necessary to differentiate STA pseudoaneurysms from more common diagnoses so that subsequent complications can be prevented. 2. Case Report A 54-year-old Caucasian male with a past medical history significant for anaplastic astrocytoma previously treated with chemoradiation was examined in the emergency department after experiencing two seizure-like episodes earlier that morning. These episodes involved rhythmic movements of the right arm, confusion, and aphasia. During the second episode, which occurred in the parking lot of the emergency department, the patient fell and repeatedly impacted the left side of his face on the pavement. Upon examination, the patient had significant abrasions to the left side of the face with a small, palpable subcutaneous mass over the left temporal region. The patient demonstrated no focal neurological deficits. A computed tomography (CT) scan of the patient’s head obtained in the emergency department