Sudden Cardiac Death as the First Manifestation of Arrhythmogenic Right Ventricular Cardiomyopathy in a Young Female Athlete: Postmortem Morphologic Diagnosis

We report a case of sudden cardiac death in a previously healthy 29-year-old female tennis player who collapsed during a family gathering with no prior cardiovascular symptoms and an unknown family history of sudden death or structural heart disease.A complete autopsy with histopathologic examination revealed a dilated right ventricle with wall thinning to 3 mm and focal transmural replacement of the myocardium by adipose tissue.Microscopically, the right ventricular wall consisted predominantly of adipose tissue, with small residual islands of hypertrophic cardiomyocytes, fibrosis, and sparse inflammatory infiltrates.A lateral left ventricular wall thickness of 15 mm, together with subepicardial fatty infiltration, prompted careful differential diagnostic consideration of athletic remodeling, hypertrophic cardiomyopathy, and biventricular or left-dominant phenotypes of arrhythmogenic cardiomyopathy.Toxicologic analysis was negative.The postmortem gross and histopathologic findings fulfilled major morphologic and histologic criteria and were highly consistent with arrhythmogenic right ventricular cardiomyopathy; however, in the absence of premortem imaging, electrocardiographic, and genetic data, this should be regarded as a postmortem morphologic diagnosis rather than a complete multiparametric diagnosis.This case underscores the diagnostic value of systematic autopsy and histopathologic examination following sudden unexplained death in young athletes, the importance of cautious interpretation of concomitant left ventricular findings, and the need for cardiovascular and genetic evaluation of first-degree relatives.