Background and importance: Aneurysms of the posterior circulation may manifest with neurological deficits related to mass effect on the brainstem. We present an unusual case of an aneurysm resulting in selective lower-extremity weakness and gait instability.
Clinical presentation: A 61-year-old man presents with progressively worsening gait instability over the course of several months. A magnetic resonance image and computed tomographic angiogram demonstrate a persistent hypoglossal artery associated with an aneurysm invaginating into the pontomedullary junction. The patient manifested only lower-extremity symptoms. An endovascular approach through the right internal carotid artery and persistent primitive hypoglossal artery was assayed, coiling off the aneurysm with complete angiographic occlusion. One month after the procedure, the patient reported marked improvement in symptoms with residual difficulty walking. At the 1-year postprocedure interval, he reported nearly complete resolution of symptoms.
Conclusion: Endovascular therapy of an aneurysm invaginating into the brainstem is safe and efficacious.