Lipomatous septal hypertrophy

Abstract

A 76-year old obese woman with a body mass index (BMI) of 36.8 was referred for evaluation of an intracardiac mass, incidentally detected with computed tomography (CT). The CT scan showed massive thickening of the intra-atrial septum with the septal tissue clearly hypointense to normal myocardium and isointense to subcutaneous fat (Figure 1, A) and sparing of the fossa ovalis (Figure 1, B, arrows). Cardiac magnetic resonance imaging confirmed septal thickening of either side of the foramen ovale (Figure 1, C, arrows), being isointense to the subcutaneous fat. Echocardiographic studies (Figure 1, D) revealed hypertrophy of the atrial septum with bright echogenicity of the thickened tissue and a typical dumbbell-shaped appearance. The diagnosis of lipomatous hypertrophy of the interatrial septum was made. Lipomatous septal hypertrophy is a rare, benign, often asymtomatic condition primarily seen in older patients and is frequently confused with other cardiac tumors.1Heyer C.M. Kagel T. Lemburg S.P. Bauer T.T. Nicolas V. Lipomatous hypertrophy of the interatrial septum: a prospective study of incidence, imaging findings, and clinical symptoms.Chest. 2003; 124: 2068-2073Crossref PubMed Scopus (157) Google Scholar, 2Nadra I. Dawson D. Schmitz S.A. Punjabi P.P. Nihoyannopoulos P. Lipomatous hypertrophy of the interatrial septum: a commonly misdiagnosed mass often leading to unnecessary cardiac surgery.Heart. 2004; 90: e66Crossref PubMed Scopus (46) Google Scholar Histologically, it is characterized by proliferation of adipocytes and interspersed hypertrophied cardiomyocytes.3Xanthos T. Giannakopoulos N. Papadimitriou L. Lipomatous hypertrophy of the interatrial septum: a pathological and clinical approach.Int J Cardiol. 2007; 121: 4-8Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar With imaging studies, lipomatous septal hypertrophy is indistinguishable from lipomas but occurs exclusively in the atrial septum and has no tendency to grow like a tumor. Massive fat deposition in the atrial wall results in a thickness of the atrial septum greater than 20 mm up to 60 mm3 and is associated with a higher incidence of atrial arrhythmias.1Heyer C.M. Kagel T. Lemburg S.P. Bauer T.T. Nicolas V. Lipomatous hypertrophy of the interatrial septum: a prospective study of incidence, imaging findings, and clinical symptoms.Chest. 2003; 124: 2068-2073Crossref PubMed Scopus (157) Google Scholar The diagnosis of lipomatous septal hypertrophy can be established by complementary imaging studies using transthoracic or transesophageal echocardiography, CT scanning, and magnetic resonance tomography. Characteristic features include a typical single mass in the interatrial septum, which is isointense to subcutaneous fat and does not involve the fossa ovalis.1Heyer C.M. Kagel T. Lemburg S.P. Bauer T.T. Nicolas V. Lipomatous hypertrophy of the interatrial septum: a prospective study of incidence, imaging findings, and clinical symptoms.Chest. 2003; 124: 2068-2073Crossref PubMed Scopus (157) Google Scholar, 4Kindman L.A. Wright A. Tye T. Seale W. Appleton C. Lipomatous hypertrophy of the interatrial septum: characterization by transesophageal and transthoracic echocardiography, magnetic resonance imaging, and computed tomography.J Am Soc Echocardiogr. 1988; 1: 450-454PubMed Scopus (27) Google Scholar In the absence of severe arrhythmias, conduction problems, or signs of obstruction owing to protrusion into the atrium, no specific therapy is required.2Nadra I. Dawson D. Schmitz S.A. Punjabi P.P. Nihoyannopoulos P. Lipomatous hypertrophy of the interatrial septum: a commonly misdiagnosed mass often leading to unnecessary cardiac surgery.Heart. 2004; 90: e66Crossref PubMed Scopus (46) Google Scholar, 3Xanthos T. Giannakopoulos N. Papadimitriou L. Lipomatous hypertrophy of the interatrial septum: a pathological and clinical approach.Int J Cardiol. 2007; 121: 4-8Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar, 5O'Connor S. Recavarren R. Nichols L.C. Parwani A.V. Lipomatous hypertrophy of the interatrial septum: an overview.Arch Pathol Lab Med. 2006; 130: 397-399PubMed Google Scholar