Iatrogenic cerebral amyloid angiopathy with inflammatory pathogenesis: A case report and literature review.

Background: Iatrogenic cerebral amyloid angiopathy (iCAA) is a rare form of amyloid β (Aβ)-mediated small vessel disease associated with prior neurosurgical exposure, such as cadaveric dura mater grafting or other Aβ-contaminated materials. The condition generally manifests decades later, presenting as intracerebral hemorrhage (ICH), seizures, or cognitive decline. While the presence of inflammatory forms of sporadic cerebral amyloid angiopathy (CAA) is well-documented, an inflammatory variant of iCAA has not been previously documented. The aims of this report are to present the first case of inflammatory iCAA, integrating clinical, radiological, and pathological findings, and to highlight its therapeutic implications. Case Description: A 38-year-old man with a medical history of cadaveric dura mater grafting in infancy presented with recurrent ICHs and progressive cognitive decline. A brain magnetic resonance imaging revealed extensive cortical superficial siderosis, leptomeningeal enhancement, and arterial wall enhancement. These features are suggestive of inflammatory CAA. Brain Biopsy revealed cortical vessel Aβ deposition and mild parenchymal lymphocytic infiltration. We diagnosed inflammatory form of iCAA with the clinical findings. Steroid pulse therapy followed by a taper of oral prednisolone led to clinical and radiological improvement, with no recurrence of symptoms or hemorrhage during 24-month period of follow-up. Conclusion: This case offers the first neuroradiological evidence of an inflammatory phenotype in iCAA. The favorable response to immunosuppressive therapy indicates that inflammation may play a pathogenic role in this case. Early immunosuppressive therapy should be considered when inflammatory features are present in iCAA.