Abstract
IntroductionNemaline myopathy is a rare genetic muscle disorder defined by the presence of nemaline rods in the muscle fibre sarcoplasm. Congenital nemaline myopathy is the most serious form of the disease’s spectrum.Case presentationThe affected newborn has no spontaneous movement, fractures at birth and respiratory insufficiency. The present case was a Thai male, floppy at birth with fractures of both humeri and femurs and ventilator-dependent respiration. The patient developed bilateral chylothorax two weeks later and died at the age of 6 weeks. Whole-body postmortem examination with informed consent and genetic analysis of ACTA1 mutation were performed. A skeletal muscle biopsy examined by light and transmission electron microscopy showed the features of nemaline myopathy. ACTA 1 heterozygous missense mutation (c.1127G > C) was identified. Histological examination of both lungs revealed primary pulmonary lymphangiectasia.ConclusionTo the best of our knowledge, congenital nemaline myopathy with primary pulmonary lymphangiectasia causing bilateral chylothrax has never been previously reported. Considering chylothorax as a poor prognostic index and an unusual clinical presentation of severe congenital NM are proposed.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9710506431489501.
Highlights
Nemaline myopathy is a rare genetic muscle disorder defined by the presence of nemaline rods in the muscle fibre sarcoplasm
Alpha-skeletal actin gene (ACTA1) heterozygous missense mutation combined with the microscopic finding of nemaline rods in the sarcoplasm warrants the diagnosis of nemaline myopathies (NM) in the present case
Recognition that chylothorax can be an unusual clinical manifestation of severe congenital NM, or other myopathies, indicates that myopathy should be included in the differential diagnosis of chylothorax in the neonate
Summary
We report a case of congenital nemaline myopathy presenting with classical features of the disease (fractures, respiratory insufficiency and absence of spontaneous movement at birth) combined with unusual presentation (bilateral chylothorax due to primary pulmonary lymphangiectasia). Together with the absence of secondary causes, this lung pathology was diagnosed as primary pulmonary lymphangiectasia. Abbreviations ACTA1: Alpha-skeletal actin gene; COX: Cytochrome oxidase; H&E: Haematoxylin and eosin; mGt: Modified Gömöri trichrome; NADH-TR: Nicotinamide adenine dinucleotide-tetrazolium reductase; NM: Nemaline myopathy; PAS: Periodic acid-Schiff; PASD: PAS with diastase; PPL: Primary or congenital pulmonary lymphangiectasia; SDH: Succinate dehydrogenase. Competing interests The authors declare no competing interests in the writing of this manuscript. JW guided the muscle diagnosis by histopathologic and electron microscopic examinations. MR reviewed lung histopathology of the present case. All authors read and approved the final manuscript
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