The hemorrhage caused by sporadic‐type cerebral amyloid angiopathy occurs primarily in the cerebral sulci

We examined a solitary hematoma in a patient with sporadic cerebral amyloid angiopathy (CAA). The hematoma affected the middle frontal sulcus, cerebral cortex (CC) and subcortical frontal white matter (sfWM). We embedded the hematoma in four paraffin blocks, each of which was cut serially into 6‐µm‐thick sections. The first section and every 18th section from each block were subjected to Elastica‐Goldner (E‐G) staining, and the distribution and diameter of the ruptured blood vessels (rBVs) were examined. The rBVs were then marked on diagrams representing each E‐G‐stained section. The present study yielded the following important findings: (i), early‐ and recently ruptured Aβ‐positive arteries were present mainly in the intrasulcal hematoma (ISH), rather than in the CC; (ii) many early‐ruptured arteries in the ISH were larger in diameter than those in the CC; and (iii) ruptures of the cortical arteries, even near the cortical surface, did not occur so frequently and the ruptured vessels were small in size. We concluded that in patients with subcortical hematoma caused by sporadic‐type CAA, successive rupturse of the meningeal vessels, mainly arteries, occur in the cerebral sulcus initially, followed by formation of an ISH and development of a fresh hemorrhagic or anemic infarct in the CC surrounding the ISH, the latter in most cases then extending into the brain parenchyma through the necrotic CC at the depth of the sulcus, finally creating a secondary hematoma in the subcortical white matter.