Clinicopathological Features of Cardiac Glycolipid Storage Disease in an Adult Pug

A 12-year-old neutered male pug suffered cardiac arrest and died under general anaesthesia during diagnostic imaging for evaluation of exercise intolerance and respiratory crisis. Histopathological evaluation revealed two types of storage material, glycolipid and lipopigment, having differential distributions in multiple organs. The heart was most strikingly affected and other less affected tissues included the liver, brain, kidneys and skin. Cardiomyocytes were swollen with extensive sarcoplasmic vacuolation together with coalescing areas of myocardial fibrosis. Transmission electron microscopy revealed irregular myelin-like structures and complex concentric lamellar bodies dominating the sarcoplasm and displacing myofibrils. These findings were consistent with a lysosomal storage disease (LSD) as the cause of cardiac disease and death. The unique clinical presentation, histomorphology and ultrastructural features of the material suggested a glycolipid storage disease most closely resembling Anderson-Fabry (Fabry) disease in man. Fabry disease is a LSD that can present in later life and is characterized by loss of α-galactosidase A function and, often, accumulation of glycosphingolipids in tissues including the heart, kidneys, vascular endothelium and smooth muscle.