Growth and regression of an intracranial vertebral artery dissecting aneurysm.

Intracranial vertebral artery dissecting aneurysms (VADAs) are rare vascular abnormalities with diverse presentations and unpredictable natural histories. Traditionally considered aggressive lesions with high mortality, emerging evidence has suggested some unruptured cases may undergo stabilization or even regression. This report details a 47-year-old patient presenting with ataxia and neck pain following a presumed traumatic dissection, leading to a diagnosis of a right vertebral artery dissection with mural hematoma formation. Serial imaging over two-years demonstrated progressive aneurysmal growth with mass effect at 6 weeks and 9 weeks, followed by stabilization at 12 months and subsequent complete regression of the aneurysm by 24 months. Conservative management was pursued due to patient preference, highlighting the importance of patient selection in decision making for VADAs. The observed spontaneous regression likely reflects a combination of mural hematoma reabsorption, closure of the dissecting flap, and robust collateral circulation. This case contributes to the evolving understanding of intracranial dissection aneurysms, emphasizing the potential for self-healing in select cases while reinforcing the need for individualized treatment strategies.