This report describes 2-week and 20-month histopathologic findings in small aneurysms embolized with platinum coils. Electron microscopy showed the presence of endothelial cells encroaching on the platinum coils at the orifice of the aneurysm in both cases. We confirm that endothelial growth can be induced as early as 2 weeks after embolization of small human aneurysms with platinum coils, similar to previous observations in animal models and human cases.