The Charcôt-Bouchard aneurysm controversy: impact of a new histologic technique.

For over a century a controversy has existed about the prevalence and significance of Charcôt-Bouchard (C-B) aneurysms, especially regarding their relationship to intracerebral hemorrhage (ICH) in man. We reassessed C-B aneurysms by staining thick brain sections from 35 hypertensives and 20 normotensives with the alkaline phosphatase (AP) endothelial stain followed by light microscopy and high-resolution microradiography. Charcôt-Bouchard aneurysms were conspicuously absent in both groups which included four cases of hypertensive ICH. The three-dimensional perspective and enhanced ability to trace vessels with these techniques helped to identify arteriolar coils and twists that can be mistaken for aneurysms when demonstrated by injection methods. Routine brain pathologic sections from 2,800 autopsies over a decade showed rare examples of parenchymal aneurysms. We conclude that elimination in our study of a) injection artifacts and b) misinterpretations shows that C-B aneurysms are uncommon and have little relationship to ICH. Despite this, and in view of the original contribution of Charcôt and Bouchard, the occasional examples of brain parenchymal aneurysms should continue to bear their names.