MELAS Presenting as Bilateral Symmetric Occipital and Temporal Cortices Lesions: A Case Report and Literature Review.

Introduction: Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode (MELAS) is one of the most common maternally inherited mitochondrial diseases. The stroke-like episode affecting the cortical cortex is the hallmark of MELAS; however, it rarely presents as simultaneously bilateral symmetric cortices lesions.

Case report: We reported a case of MELAS in a 46-year-old female patient with bilateral symmetric occipital and internal temporal cortices involvements on brain magnetic resonance imaging (MRI). A literature review of MELAS patients and a retrospective analysis were performed. She had a family history of diabetes. Although she denied a history of diabetes, elevated blood glucose was noted after admission, and diabetes was diagnosed. Laboratory examination revealed elevated lactate acid and creatine kinase levels in blood. Cranial computed tomography (CT) image demonstrated basal ganglia calcification, as well as subtle decreased attenuation in bilateral symmetric occipital and internal temporal cortices. Brain magnetic resonance imaging (MRI) demonstrated symmetric gyriform hyperintensity in bilateral occipital lobes and internal temporal lobes in both grey and white matter on fluid-attenuated inversion recovery (FLAIR) images with restricted diffusion on diffusion weighted images (DWI). A genetic test revealed a point mutation in the mtDNA(3243A > G) by blood examination. Literature review showed that there were 231 eligible patients with MELAS identified from 212 published papers. Symmetric cortical involvements were seen in 15 (6.5%) patients on brain MRI.

Conclusions: MELAS should be considered as a potential diagnosis in the patients with bilateral symmetric stroke-like cortices lesions.