Histiocytoid cardiomyopathy (HC) is a very rare cardiac disorder that mainly affects female infants younger than 2 years. It may manifest as ventricular tachycardia or dilated cardiomyopathy and frequently causes sudden death. The most common grossly change is multifocal uneven thickening of the endocardium, presenting a yellowish color, with some area forming nodular appearance, and histologically featured by scattered clusters of histiocytoid myocytes under the endocardium. Here, we present a 19-month-old male infant who died of heart failure, and an autopsy was performed and confirmed the diagnosis of HC. We also reviewed the literature and focused on the research progression of the origin and genetic/molecular features of HC in recent years.