Histopathology of Cerebral Aneurysms

Saccular cerebral aneurysms of nonmycotic origin are of considerable importance in cerebrovascular pathology and neurosurgery, but their etiology has remained a controversial subject for many years. Hassler¹contends that 2 fundamentally. opposed views emerge from the many theories propounded. One view assumes that a major congenital or developmental factor is responsible and the other considers that aneurysms are the result of postnatal changes in the arterial wall. Naturally, the combination of acquired and congenital factors is also possible, and in recent years Carmichael,²,³Walker and Allègre,⁴,⁵and Crawford⁶have supported this view. However, the findings of Glynn⁷and Stehbens⁸⁻²⁰argue against the "congenital theory," though further evidence is necessary. In this histological study of cerebral aneurysms, emphasis has been placed on early aneurysmal changes, and the investigation was aimed at providing information on the following: 1. Earliest demonstrable histological evidence of aneurysms and the