Lipomatous hypertrophy of the interatrial septum on PET-CT

Case contributed by Dr Dalia Ibrahim


Incidental finding on PET-CT scan.

Patient Data

Age: 50 years
Gender: Female

FDG avid smooth, non-enhancing, well-marginated fat-containing lesion in the interatrial septum.

Case Discussion

Lipomatous hypertrophy of the interatrial septum (LHIS) is a relatively uncommon disorder of the heart characterized by benign fatty infiltration of the interatrial septum. It is commonly found in elderly and obese patients as an asymptomatic incidentally discovered finding. 


Usually shows moderate degree of FDG-uptake. It may vary on serial studies and the FDG-avidity was initially thougt to be caused by metabolic activity of brown adipose tissue (BAT) 12,13. More recently this theory has been questioned by other authors, with suggestion of either inflammation or an hitherto unidentified mechanism of BAT activation as potential mechanism 14.

Be that as it may, there is consensus on the necessity of hybrid imaging and correlation with former imaging studies to avoid misclassification.

This case is courtesy of Dr Sherif El Refaie & Dr Mohamed Shahin

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Case information

rID: 42422
Published: 19th Jan 2016
Last edited: 16th Jul 2018
System: Cardiac, Vascular
Inclusion in quiz mode: Included

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