18F-FDG PET/CT helps rule out malignancy in lipomatous hypertrophy of the interatrial septum with atypical MRI manifestations, to avoid unnecessary surgical treatment.

Lipomatous hypertrophy of the interatrial septum (LHIS) is a rare benign heart disease characterized by excessive deposition of adipose tissue in the atrial septum with sparing fossa ovalis, which demonstrates a characteristic hourglass/dumbbell configuration. We reported a case of LHIS with inhomogenous characteristic on CMR and persistently no FDG uptake on 18F-FDG PET-CT, which is contrary to a few previous cases. This single case report suggests that in case LHIS present in-homogenous characteristic on CMR, metabolic PET imaging could be used as a complementary imaging model to decrease the concern of lipomatous neoplasms, thereby avoid unnecessary surgical therapy.