Coexistence of various vascular malformations within the brain.

Authors present two cases of basilar artery aneurysm accompanied by different development failures of blood vessels. In both cases anomaly in formation of brain base vessels, angioma consisted of different size thin-walled vessels and arterio-venous angioma within brain stem were stated. Besides, conglomerates of abnormal vessels, angiosis within pia matter, diffused lacunar and fetal as well as thin-walled venous vessels were found. Pathological vessels, their conglomerates were present in brain stem, cerebellum and cerebral hemispheres. The variability of vascular malformations seems to point at long-lasting action pathogenic factor during ontogenesis. Authors try to refer particular developmental anomalies to proper stage of ontogenesis.