Dissecting intracranial aneurysm.

A case of spontaneous dissecting aneurysm of the right internal carotid and middle cerebral arteries is presented in 13-year-old boy. The pathogenetic factors incriminated in previously reported cases are reviewed and the pathological findings are discussed. The abnormalities of the internal elastic lamina as seen in this patient have been observed in numerous cases of intracranial dissecting aneurysms. It is concluded that these defects play an important role in the development of dissection.