Introduction Aneurysms of lenticulostriate artery (LSA) perforators are uncommon. There are few data on their natural history, and opinions differ on the treatment strategies.

Objective We report a case series and summarize the most recent literature with current treatment recommendations. We propose an anatomical classification for these entities.

Methods A retrospective review of all patients who were diagnosed with an LSA aneurysm on cerebral angiogram was performed. An extensive online literature search was performed to identify other studies reporting on the diagnosis and management of ruptured and unruptured lenticulostriate aneurysms.

Results 48 cases were identified in the literature and reviewed: 27 patients were treated surgically; five cases were treated with endovascular therapy; two cases underwent gamma knife radiosurgery; and 13 cases were managed conservatively. We classified these aneurysms into three types: type 1 describes aneurysms arising from the middle cerebral artery next to a perforating LSA; type 2 is an LSA aneurysm from which the perforating artery or arteries arise—the type 2A subtype is one in which the aneurysm neck incorporates the origin of the perforating arteries and the type 2B describes perforating arteries arising from the dome of the aneurysm; and type 3 describes a fusiform aneurysm beyond the first loop or turn of an LSA.

Conclusions LSA aneurysms are rare entities that present several treatment challenges. We have summarized the cumulative experience with these lesions and proposed a classification scheme that has treatment implications.