Background - Cerebral amyloid angiopathy-related inflammation (CAA-ri) is characterized by various neurological symptoms such as gradually developing confusion, progressive cognitive decline, seizure or headaches; T2 hyperintensities on magnetic resonance imaging (MRI); and neuropathological evidence of cerebral amyloid angiopathy (CAA) and associated vascular or perivascular inflammation. Although histological confirmation is necessary for accurate diagnosis, in case of typical clinical features and neuroimaging, the diagnosis can be established without biopsy. Case summary - We present the case of a 57-year-old man with a history of hypertension who presented to the emer¬gency department 3-week history of progressive headache and a gradually developing altered mental status. On examination, he was found to have left sided weakness and decreased pscyhomotility. Routine clinical work-up (lab investigations, CT, cerebrospinal fluid analysis) did not show obvious diagnosis, so we performed an MRI. It raised the suspicion of CAA-ri which diagnosis was verified by neuroradiological evaluation. High dose steroid treatment was initiated. The patient rapidly responded to treatment, his focal neurological signs resolved. Control MRI after 1.5 months showed multiple haemorrhagic laesions in the field of previous inflammation which posteriorly supported the previous supposed work-diagnosis. Conclusions - Although histopathology is the gold standard for the diagnosis of cerebral amyloid angiopathy, the typical clinical presentation, good response to steroids and accurate neuroradiological criteria make biopsy unnecessary to diagnose CAA-ri.