Spontaneous regression of an incidental brain venous aneurysm in a child and literature review

Background: Brain venous aneurysms (BVAs), also known as isolated cerebral varices, are rare vascular anomalies characterized by focal dilatation of a cerebral vein. Isolated BVAs are exceptionally uncommon. Most BVAs are asymptomatic and incidentally identified, yet they may present with hemorrhage, seizures, or focal deficits due to mass effect. Case Description: We report a case of a 15-year-old boy who first presented at the age of eight to the emergency department after a minor bicycle-related head trauma. Computed tomography imaging revealed a round, iso- to slightly hyperdense lesion in the right Sylvian fissure. Subsequent magnetic resonance imaging demonstrated an extra-axial, well-circumscribed mass measuring 18 × 22 × 18 mm, iso- to hyperintense on T1 and hyperintense on T2/fluid-attenuated inversion recovery, suggesting a vascular malformation. Digital subtraction angiography confirmed the diagnosis of an isolated cerebral venous aneurysm. Regarding the patient’s young age, lack of symptoms, and unruptured presentation, conservative management with annual MRI follow-up was chosen. Over the following years, serial MRIs showed progressive spontaneous regression, decreasing to 6 mm by 2025, with the patient remaining asymptomatic. Conclusion: Isolated BVAs are rare lesions with variable clinical behavior. While some advocate early intervention, conservative management is appropriate for asymptomatic, low-flow, isolated venous aneurysms. Spontaneous regression, although uncommon, is well-documented, as observed in our case.