Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) is a disease more commonly seen in pediatric populations, rarely with adult onset. This case reports MELAS in a 60-year-old female with progressive aphasia and encephalopathy after abnormal MRI raised concerns for alternative diagnosis with goals of adding to the current limited database of adult onset MELAS.

Patient without pertinent family history or previous symptoms initially presented with minimal intermittent word finding difficulties for two months followed by acute onset of significant expressive and comprehensive aphasia. MRI brain showed temporal lesions with restricted diffusion in a gyral pattern, which is atypical for stroke.  Additional workup negative, including lumbar puncture. Telemetry revealed Atrial fibrillation. Patient discharged on Eliquis and Depakote given concerns of epileptogenicity of temporal lobe lesions. Patient’s clinical course declined with worsening of gait, inability to follow more complex commands and homicidal ideations. Repeat outpatient MRI brain showed progressive frontotemporal DWI and FLAIR changes concerning for autoimmune encephalitis, vasculitis or low-grade glioma. On readmission, exam significant for global aphasia and transient right arm weakness.

This case highlights the importance of considering MELAS in suspected stroke with continued clinical deterioration and progressive MRI changes.