Subcortical hematoma caused by cerebral amyloid angiopathy: Does the first evidence of hemorrhage occur in the subarachnoid space?

Abstract

Six autopsy cases of subcortical hematoma caused by CAA were examined to elucidate the primary site of hemorrhage. Immunohistochemistry for amyloid beta-protein (A beta) revealed extensive CAA in the intrasulcal meningeal vessels rather than in the cerebral cortical vessels. All of the examined cases had multiple hematomas in the subarachnoid space, mainly in the cerebral sulci, as well as intracerebral hematomas. Each intracerebral hematoma was connected to the subarachnoid hematomas at the depth of cerebral sulci or through the lateral side of the cortex. There was no debris of the cerebral cortical tissue in the subarachnoid hematomas. In case 2, another solitary subarachnoid hematoma, which was not connected to any intracerebral hematoma, was seen. In all of these subarachnoid hematomas, many ruptured A beta-immunopositive arteries were observed. These ruptured arteries did not accompany any debris of the brain tissue, some of them were large in diameter (250-300 microm), and several of them were far from the cerebral cortex. Therefore, it was considered that they were not cortical arteries but meningeal arteries. Within the cerebral cortex, there were only a few ruptured arteries associated with small hemorrhages. There were no ruptured vessels within the intracerebral hematomas. There was a strong suggestion that all of the subarachnoid hematomas, including the solitary one in case 2, originated from the rupture of the meningeal arteries. The present study indicates that in some cases of subcortical hematoma caused by CAA, the primary hemorrhage occurs in the subarachnoid space, in particular the cerebral sulci, because of rupture of multiple meningeal arteries. Infarction occurs subsequently in the cortex around the hematoma, the hematoma penetrates into the brain parenchyma, and finally, a subcortical hematoma is formed.

Subarachnoid Hemosiderosis and Superficial Cortical Hemosiderosis in Cerebral Amyloid Angiopathy

“…This has also been suggested in cases of familial leptomeningeal amyloidosis. 8,9 A neuropathologic study by Takeda et al 10 further supports this hypothesis, as it shows that in some cases of CAA the primary hemorrhage occurs in the subarachnoid space.…”

Prevalence and mechanisms of cortical superficial siderosis in cerebral amyloid angiopathy

“…A small neuropathologic series of 6 autopsy cases of subcortical hematoma caused by CAA showed that at least in some cases the primary hemorrhage appeared to originate from the subarachnoid space. 22 Further prospective studies are urgently required to determine the risk of future intracranial bleeding associated with cSS in CAA.…”

Cortical superficial siderosis and intracerebral hemorrhage risk in cerebral amyloid angiopathy

“…30 Indeed, a neuropathologic series of 6 autopsy cases of subcortical hematoma caused by CAA showed that multiple leptomeningeal arteries can rupture into the subarachnoid space and the brain parenchyma. 30 This hypothesis is supported by the observation that symptomatic ICH has been noted at (or close to) the site of previous siderosis, 15 although we found that ICH only occurred at the site of cSS in 50% of cases. We found the highest ICH risk in patients with disseminated cSS, which may indicate widespread and numerous leptomeningeal vessels damaged by advanced CAA, providing multiple potential initiation sites for future ICH, increasing the probability of this outcome.…”