A unilateral partial duplication of a fetal variant posterior cerebral artery associated with anomalous origin of duplicated superior cerebellar artery: a case report.

Variations at the junction of embryonic internal carotid and vertebrobasilar systems are rare and associated with a high incidence of stroke. During cadaver dissection, we demonstrated for the first time a case of hypoplastic right vertebral artery associated with partial duplication of the distal part of the right P1 segment of a partial fetal posterior cerebral artery (FPCA) and bilateral duplication of superior cerebellar arteries (SCAs), of which, the upper right SCA originated from PCA. We hypothesize that the poor development of the right half of the vertebrobasilar system caused the persistence of FPCA with anomalous origin of the right upper SCA as well as partial duplication of P1 segment of PCA as a remnant of the weak anastomosis between the embryonic right PCA and the basilar system. Such complex variations provide a huge challenge in their diagnosis and in choosing the suitable treatment modality for the stroke.