A 69-year-old woman presented with transient spreading sensory symptoms in the left upper limb compatible with a transient focal neurological episode (TFNE). MRI performed 3.5 hours later revealed an acute focal right rolandic convexity subarachnoid hemorrhage (cSAH), seen as hyperintensity on fluid-attenuated inversion recovery (FLAIR; figure 1A–C, arrows) and as hypointensity on T2*-weighted imaging (figure 1D, arrow). Associated FLAIR hypointensities were observed in the corticosubcortical brain areas adjacent to the cSAH (figure 1A–C, arrowheads), with a mean signal intensity of 139 in the visually involved right perirolandic corticosubcortical area compared with a mean signal intensity of 174 in the contralateral left perirolandic corticosubcortical mirror area. Diffusion-weighted imaging (and apparent diffusion coefficient) were strictly normal. Multifocal cortical superficial siderosis on T2*-weighted imaging (figure 1E,F, arrowheads) evoked underlying cerebral amyloid angiopathy (radiological abnormalities corresponded to possible cerebral amyloid angiopathy according to the modified Boston criteria). Two weeks later, the subarachnoid and adjacent corticosubcortical FLAIR signal changes normalised (figure 1G–I), with a mean signal intensity of the corresponding earlier involved perirolandic corticosubcortical area of 172 on the right and 173 on the left side.