Lipomatous hypertrophy of the interatrial septum: report of an unusual case

Abstract

Sir: Lipomatous hypertrophy of the interatrial septum (LHIS) is an uncommon lesion rarely encountered as a surgical specimen. I present an atypical case which is

Intrinsic and Extrinsic Cardiac Pseudotumors: Echocardiographic Evaluation and Review of the Literature

“…Lipomatous hypertrophy of the interatrial septum (LHIS) was first described in 1964 by Prior . Since then, there have been approximately 200 cases described in the literature . LHIS is a rare, benign lesion (incidence 1.1–2.2%) that is usually asymptomatic, and the diagnosis is incidentally made during imaging or at autopsy .…”

“…Since then, there have been approximately 200 cases described in the literature . LHIS is a rare, benign lesion (incidence 1.1–2.2%) that is usually asymptomatic, and the diagnosis is incidentally made during imaging or at autopsy . Interatrial septal thickening can occur on either side of the septum with the greatest thickness usually superior to and sparing the fossa ovalis .…”

“…Rarely, LHIS can be diffuse with intra‐cavitary or intramural extensions into the heart chambers . The symptoms of LHIS include the following: a variety of atrial arrhythmias including supraventricular arrhythmias, conduction disturbances (AV block), heart failure, altered hemodynamic cardiac function, recurrent pericardial effusions, congestive heart failure, and rare unexpected sudden cardiac death . Histology of LHIS shows an unencapsulated lesion of mature fat cells, and fat cells that resemble brown fat cells (fetal fat cells) interspersed throughout cardiomyocytes that are often hypertrophied with oddly shaped nuclei without mitosis present .…”

“…Cardiac MRI allows the distinction of tissue character and anatomic extension which can then be used to design a strategy for surgery and also to differentiate LHIS from both liposarcoma and lipoma . Most patients with LHIS are asymptomatic and usually no action is taken if the diagnosis is certain . If patients with LHIS exhibit severe arrhythmias, conduction problems, intractable rhythmic disturbances, or signs of obstruction attributed to the lesion, surgical intervention can then be used to alleviate these symptoms in select cases .…”

“…71,72 LHIS is a rare, benign lesion (incidence 1.1-2.2%) that is usually asymptomatic, and the diagnosis is incidentally made during imaging or at autopsy. 10,72,73 Interatrial septal thickening can occur on either side of the septum with the greatest thickness usually superior to and sparing the fossa ovalis. [72][73][74] Criteria for diagnosing LHIS includes septal thickness between 15 and 20 mm (more commonly 20 mm) although the septal thickness range is highly variable and has been observed up to 150 mm.…”