The micro-pathological characteristics in cerebral arteriovenous malformations(cAVMs)

Rupture and hemorrhage is the most serious complication of cerebral arteriovenous malformation(cAVMs), and have a significant impact on quality of life.We investigated the hematoxylin and eosin staining and ultrastructural features of cAVMs and characterized the abnormal vascular structure of cAVMs.Light and electron microscopy were performed on a series of pathological specimens obtained from 12 patients with cAVMs who underwent surgical resection for the first time without radiosurgery or embolization therapy.In tunica intima, we found that the vascular endothelial cells of cAVMs were damaged, and the lysis of the cell body occurred in multiple regions. In tunica media, the arrangement of the elastic layer was disordered, and the thickness was uneven. Part of the structure of the elastic lamina was missing. The part of tunica adventitia was fractured and discontinuous. In addition, we also observed the phenomenon that different blood vessels share the same vascular wall. Macrophage phagocytosis and lymphocyte infiltration in the adventitial region of ruptured cAVMs. Abnormal lipid deposition in vascular endothelial cells and smooth muscle cells.The structural incompleteness of cAVMs may be an important cause of hemorrhage.