Ultrastructural and clinical findings of mitochondrial encephalomyopathy:report of 27 cases
10.3760/cma.j.issn.0529?5807.2019.04.007
- VernacularTitle:线粒体脑肌病27例临床特点及超微结构观察
- Author:
Qi ZHANG
1
;
Yilin SUN
;
Cuiping ZHANG
;
Baoqing QU
;
Zaiqiang ZHANG
Author Information
1. 北京市神经外科研究所首都医科大学附属北京天坛医院100070
- Keywords:
Mitochondrial encephalomyopathies;
Microscopy,electron;
Intranuclear inclusion bodies
- From:
Chinese Journal of Pathology
2019;48(4):298-302
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the ultrastructural features of muscle in patients with mitochondrial encephalomyopathy for its diagnosis and differential diagnosis.Methods The clinical data of 27 mitochondrial encephalomyopathy patients who underwent left or right biceps brachii muscle biopsy at Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University from July 2006 to August 2017 were analyzed retrospectively. The muscle biopsy specimens were examined underlight microscope and transmission electron microscope.Results There were 27 patients (17 males, 10 females) with an age range of 12 to 62 years (mean 29 years). The age of onset ranged from 3 to 38 years. The course of disease ranged from 1 month to 24 years. Twenty?two cases presented with lactic acidosis and stroke?like episodes (MELAS) syndrome, four with myoclonic epilepsy with ragged red fibers (MERRF) syndrome, and one with chronic progressive paralysis of extraocular muscle (CPEO) syndrome. Skeletal muscle biopsy showed abundant ragged red fibers and strongly SDH?reactive vessel. Genetic studies showed 17 of 22 cases of MELAS syndrome had A3243G mutation, and the other 5 cases had no abnormality. A8344G mutation was found in 3 of 4 cases of MERRF syndrome. No single or multiple mtDNA mutations were found in the single case of CPEO. Transmission electron microscopy of all 27 cases showed diffuse proliferation of mitochondria between the myofibrils and beneath the sarcolemma, with increased spacing between muscle cells. Seven cases showed numerous glycogen and four showed subsarcolemmal lipid droplets, 13 cases showed unusual mitochondrial morphology, including mitochondrial electron?dense substances and paracrystal line inclusions ("parking lot" change)in eight cases. Conclusions Transmission electron microscopy shows significant differences in ultrastructural pathological changes among different patients with mitochondrial encephalomyopathy. Some patients with mild clinical symptoms have increased mitochondrial number, increased metabolism of glycogen and lipid droplets, while others with severe clinical symptoms have abnormal mitochondrial morphology. Typical crystalloid inclusions are found in mitochondria, which are of great value in the diagnosis of this disease.
