From stroke workup to mitochondrial disease: A case report of MELAS.

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a rare mitochondrial disorder that often presents with recurrent neurological deficits mimicking ischemic stroke. However, MELAS lesions characteristically violate vascular territories, a pattern that may be underrecognized in adult patients, particularly when vascular risk factors confound clinical suspicion. We present a case of a 36-year-old male with type 2 diabetes, tobacco use, and alcohol use disorder who experienced multiple recurrent stroke-like episodes involving the temporal and parietal lobes. Despite an extensive negative vascular and infectious workup, serial MRI demonstrated multifocal cortical and subcortical T2/FLAIR hyperintensities with restricted diffusion and evolving lesion patterns inconsistent with a vascular etiology. MR findings were suggestive of both cytotoxic and vasogenic edema, further supporting a metabolic cause. Genetic testing ultimately confirmed a heteroplasmic pathogenic variant in the MT-TL1 gene, consistent with MELAS. This case underscores the critical role of radiologic pattern recognition in diagnosing MELAS and the importance of distinguishing stroke-like lesions from true infarcts to guide appropriate clinical management.