MELAS: A Complex and Challenging Diagnosis.

Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is a rare multisystem disorder and is the most common maternally inherited mitochondrial disease. This condition has a special predilection for the nervous system and muscles. Typical findings on brain imaging include stroke-like areas, calcification of basal ganglia and brain atrophy. This accounts for the disease being, both clinically and radiologically, mistaken for ischemic stroke. The differentiation features from stroke include comparatively young age of the patients, site of the lesions, and relative overlap between the cerebral vasculature territories. In this case report, we discuss a 16-year male with clinical and radiological features highly suggestive of MELAS syndrome. Since this disease is rare and its clinical presentation is complex, it is among the most challenging to diagnose. It is particularly difficult to differentiate between ischemic stroke and MELAS. Magnetic resonance imaging (MRI) with diffusion weighted imaging (DWI), susceptibility weighted imaging (SWI) sequences and MR spectroscopy may aid in establishing the diagnosis. A particularly characteristic feature of MELAS syndrome is that recurrence may occur in locations different than previously noted, which was also seen in our patient.