Microbleeds within Mitochondrial Stroke-Like Lesion Rather Result from Their Vulnerability Than from Microangiopathy

Abstract

MELAS syndrome (mitochondrial encephalopathy, lactic acidosis, and stroke-like episode) is one of the most common syndromic mitochondrial disorders (MID) and is due to the variant m.3243A>G in MT-TL1 in approximately 80% of cases. MELAS is a multisystem disorder with stroke-like episodes (SLEs) as a pathognomonic feature. The morphological correlate of SLEs in cerebral imaging are stroke-like lesions (SLLs). SLLs present on cerebral MRI with a T2, FLAIR, DWI, and PWI-hyperintense and OEF-hypointense lesion that is not confined to a vascular territory and extends to a nadir before disappearing or terminating as a structural lesion. Occasionally, these features are accompanied by microbleeds within the SLL, usually along the cortex. These microbleeds are thought to result from laminar cortical necrosis, and end-stage of a SLL or seizures, a common manifestation of SLEs.