Neonatal Sudden Death Due to Histiocytoid Cardiomyopathy

Histiocytoid cardiomyopathy, an extremely rare heart disease in infants and children, usually occurring in girls under the age of 2 years, is characterized by cardiomegaly, ventricular arrhythmia, and sudden death. In the present study, we report a case of a 2-day-old female neonate who suddenly showed cyanosis and cardiac arrest in the neonatal unit and died without resuscitation. Autopsy revealed multifocal nodular lesions in the left ventricle wall and papillary muscles. Microscopically, these lesions were composed of discohesive round or polygonal cells with eosinophilic cytoplasm and were positive for desmin and negative for CD68. Electron microscopy findings displayed abnormal swollen mitochondria with disorganized cristae, dense granules, and diminished myofibrils in the periphery of the cytoplasm.