Hypertrophic Obstructive Cardiomyopathy in An Infant with Hemophagocytic Lymphohistiocytosis; Answer to a Riddle

Summary: Familial hemophagocytic lymphohistiocytosis (FHLH) is a hereditary hyperinflammatory condition with T-cell and macrophage activation. Treatment consists of immunosuppressive therapy plus bone marrow transplantation. Cardiac manifestations of FHLH were scarcely mentioned in the literature with conflicting pathophysiological explanations. We report a case of hypertrophic obstructive cardiomyopathy associated with FHLH. Guided by such a case, a clear vision regarding the real cause is thought to be obtained in the cloudy landscape of pathophysiology.