Objective and importance: Fenestrations of cerebral arteries are rare, but very important to diagnose given their high association with saccular aneurysms. We present the first reported case of a fenestration of the posteroinferior cerebellar artery (PICA).
Clinical presentation: A 62-year-old man who presented with a subarachnoid hemorrhage underwent repeated four-vessel cerebral angiography. An isolated right PICA abnormality consistent with a dissection or fenestration was revealed.
Intervention: The patient underwent surgical exploration of his PICA, which confirmed a PICA fenestration without an associated saccular aneurysm. The fenestration was wrapped with cotton.
Conclusion: Our case report illustrates the novel anatomic finding of a fenestration of the PICA. Knowledge of this entity would be helpful in the differential diagnosis of a posterior fossa subarachnoid hemorrhage.