title: CT appearance of lipomatous hypertrophy of the interatrial septum.
abstract: OBJECTIVE
  We undertook this study to determine the CT findings of lipomatous hypertrophy of the interatrial septum, an asymptomatic and underrecognized benign proliferation of fat within the atrial septum.
  
  
  METHODS
  We retrospectively identified 12 cases of lipomatous hypertrophy of the interatrial septum by searching the radiology records at our institution from 1991 to 1995. We reviewed the CT scans of these patients to determine the distribution and morphology of fat within the interatrial septum.
  
  
  RESULTS
  In all patients with lipomatous hypertrophy, a mass of fat attenuation extended from the coronary sinus to just above the level of the aortic root with relative sparing of the fossa ovalis, which resulted in a dumbbell configuration. Average dimensions were 7 cm for craniocaudal extent (range, 6-9 cm), 4.5 cm along the interatrial septum (range, 3.6-6.2 cm), and 2.7 cm perpendicular to the septum (range, 1.5-4.8 cm). Increased epicardial fat was seen on CT scans in 10 patients (83%). CT revealed mediastinal lipomatosis in six patients (50%). No patients had undergone corticosteroid treatment or total parenteral nutrition. No electrocardiographic or functional cardiac abnormalities were seen.
  
  
  CONCLUSIONS
  On standard, high-resolution, and enhanced CT images, lipomatous hypertrophy of the interatrial septum is shown as a nonenhancing smoothly marginated homogeneous dumbbell-shaped mass of fat attenuation confined to the interatrial septum. These characteristic morphologic features allow confident diagnosis and help differentiate this benign condition from other cardiac masses.
authors.affiliation: Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0326, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Meaney
authors.forename: E A
authors.initials: EA
authors.lastname: Kazerooni
authors.forename: D A
authors.initials: DA
authors.lastname: Jamadar
authors.forename: M
authors.initials: M
authors.lastname: Korobkin
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D009202:Cardiomyopathies / Q000000981:diagnostic imaging; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006346:Heart Septum / Q000000981:diagnostic imaging*; D006801:Humans; D006984:Hypertrophy; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed