Glycogen storage disease type II (Pompe disease) presenting with peripheral lymphadenopathy in a juvenile domestic shorthair cat

Abstract

This report describes a 13‐month‐old, female, spayed domestic shorthair cat that had, at 8 months of age, an initial diagnosis of severe left ventricular concentric hypertrophy with differentials including juvenile hypertrophic cardiomyopathy, mitral valve dysplasia, infiltrative disease or, less likely, ventricular non‐compaction. On final emergency presentation, it had diffuse peripheral lymphadenopathy and bicytopenia. Postmortem transmission electron microscopy of formalin‐fixed heart tissue provided a definitive diagnosis. It revealed distended secondary lysosomes packed with glycogen beta particles, pathognomonic for glycogen storage disease type II.