Mitochondrial encephalomyopathy with lactic acidemia and stroke-like episodes

Abstract

Objective To study histological features, immunophenotype, genotype, diagnosis and differential diagnosis, treatment and prognosis of one case of mitochondrial encephalomyopathy with lactic acidemia and stroke-like episodes (MELAS), and to summarize the clinicopathological features and key points of diagnosis and differential diagnosis. Methods and Results A 55-year-old female presented language disorder with memory disorders for 2 months, and her head MRI showed space-occupying lesion of left temporal lobe. An exploratory craniotomy was performed. Histological morphology showed patchy grey and white matter structure, scattered hemorrhagic necrosis, small vascular hyperplasia, luminal hyperemia and vasodilatation, and scattered lymphocytic infiltration. By using immunohistochemical staining, the membrane of lymphocytes was focally positive for CD3 and CD20, and neurons were positive for neuronal nuclei (NeuN). Periodic acid-Schiff (PAS) staining was focally positive. In further musc le biopsy, modified Gomori trichrome (MGT) staining showed a lot of scattered ragged-red fibers (RRF), suggesting myopathologic change of mitochondrial encephalomyopathy. A m.3243A > G mutation (about 9%) was found in the direct sequencing genetic testing. The final diagnosis was MELAS. After operation, the patient received antiepileptic, hypoglycemic and neurotrophic treatment. Conclusions Adult-onset MELAS is a rare disease with various clinical manifestations. A definite diagnosis depends on clinical manifestations, histopathological characteristics, immunophenotype and genetic testing. DOI: 10.3969/j.issn.1672-6731.2018.11.011

Keywords

• MELAS syndrome
• Immunohistochemistry
• Pathology