Rete mirabile of posterior inferior cerebellar artery: A rare cause of subarachnoid hemorrhage.

Rete mirabile is a congenital aberrant arterial collateral network resulting from abnormal embryonic activity during native vessel formation. Even though frequently observed in mammals, this entity is rare in humans except when there is hypoplasia, aplasia or narrowing of native vessels. Rete mirabile is reported involving internal carotid and vertebral arteries. Rete mirabile of the posterior inferior cerebellar artery (PICA) is not described in the literature. We report the clinical presentation, imaging findings and management of PICA rete mirabile formation with subarachnoid hemorrhage.