Pseudoaneurysm as a differential for the computed tomography angiography “spot sign” in atypical presentations of intracerebral hemorrhage: illustrative case

BACKGROUND: The computed tomography angiography (CTA) “spot sign” is a well-recognized radiographic marker in primary intracerebral hemorrhage (ICH). Although it has been demonstrated to represent an area of active hemorrhage or contrast extravasation, the exact pathophysiology remains unclear. Vascular mimics of the spot sign have been identified; however, those representing pseudoaneurysm and small vessel aneurysm have rarely been reported. OBSERVATIONS: A 57-year-old female with a past medical history of hypertension and diabetes mellitus presented with 2 weeks of acute-onset, worsening headache. Computed tomography scanning showed a right interior frontal lobe intraparenchymal hemorrhage. CTA demonstrated a punctate focus of hyperattenuation within the hematoma, consistent with a spot sign, which corresponded to a distal anterior cerebral artery pseudoaneurysm on a cerebral angiogram. The patient subsequently underwent emergent resection of the pseudoaneurysm and hematoma evacuation without complications. Her postoperative course was unremarkable without acute concerns or residual symptoms at the 4-month follow-up. LESSONS: The authors present a unique case of a distal anterior cerebral artery pseudoaneurysm presenting as a spot sign in a relatively young patient without underlying vascular disease. Given the need for emergent intervention, intracranial pseudoaneurysm is an important diagnosis to consider in the presence of a spot sign in atypical clinical presentations of primary ICH.