A vertebral artery aneurysm is a rare occurrence in clinical practice and commonly develops after penetrating trauma that disrupts the anatomy of this blood vessel. Risk factors that are infrequently present are hypertension and coronary heart disease. Headaches and altered consciousness are the most common symptoms. The diagnosis is made through imaging studies, such as computed tomography and digital subtraction angiography, but magnetic resonance angiography is considered to be the optimal procedure for evaluating the lesion.
Vertebral artery aneurysms (VAA) primarily develop at the junction of this vessel and the posterior inferior cerebellar artery (PICA) and are responsible for approximately 0.5-3% of all intracranial aneurysms reported in the literature . Penetrating trauma, such as gunshot or stab wounds, is by far the most important cause of VAA, whereas blunt force trauma, atherosclerosis, fractures of the vertebral column, rheumatoid arthritis (RA), and syphilis are described as other potential etiologies . Aneurysms of this vessel might rupture and induce subarachnoid hemorrhage (SAH) or cause infarction on the grounds of ischemia and thromboembolism , but VAAs can arise from previous dissection as well    . The clinical presentation is comprised of two major symptoms - headache and an altered consciousness, ranging from mild changes to severe coma . Other notable signs that are described in patients who suffered from a vertebral artery aneurysm are vertigo, vomiting, nausea, and Wallenberg syndrome (also known as lateral medullary syndrome)  . Some authors report that a pulsating mass may be a feature of a VAA, often accompanied by bruits and thrills that are aggravated when the carotid artery is compressed .
The diagnosis of a vertebral artery aneurysm must be made early on, which is why a thorough clinical and imaging workup is recommended as soon as suspicion toward this medical entity is raised. The physician should first obtain a detailed patient history that evaluates cardiovascular risk factors and the presence of other comorbidities. If penetrating trauma of the posterior cervical area is confirmed, employment of imaging studies is mandatory. Computed tomography (CT) and magnetic resonance imaging (MRI) must be initially performed to assess the surrounding tissues, but in order to make a definite diagnosis of a VAA, vascular-enhancing studies are necessary. CT angiography (CTA), with or without 3D reconstruction, MR angiography (contrast enhanced and 3D reconstruction) and digital subtraction angiography (DSA) have all been recommended in the assessment of the cranial circulation  . Because of the limitations of CTA (overlapping with bony structures and time-consuming) and DSA (limited capacity to reveal atypical aneurysms), MR angiography is considered to be the gold standard  . On these studies, radiologists frequently reveal the "pearl and string sign" - dilation of the vessel in a fusiform pattern with irregular narrowing of the lumen, whereas subarachnoid hemorrhage, thrombosis, or the formation of a vertebral-venous fistula can be observed as well   .