Cerebral amyloid angiopathy (CAA) is a degenerative disorder characterized by the deposition of β-amyloid peptide in the cortical and leptomeningeal arteries and capillaries. The incidence of CAA increases with age, accounting for 5–20% of non-traumatic spontaneous ICH in the elderly. Diagnosing CAA is essential for assessing the risk of ICH recurrence. It is also necessary for guiding treatment decisions, as the use of anticoagulation, thrombolytics, and antiplatelets increase the risk of hemorrhage in vulnerable vessels. According to the Boston criteria, a definite diagnosis of CAA-related ICH requires evidence of lobar or cortico-subcortical hemorrhage and consistent pathology on postmortem examination. A diagnosis of probable CAA with supporting pathology can be made with a biopsy of the hematoma or cerebral cortex.

In cases of lobar hemorrhage requiring hematoma evacuation, biopsy with amyloid staining can provide diagnostic clarity and guide further management. This is especially useful in situations of competing etiologies like hypertension and when neuroimaging does not have additional supportive features of CAA.