Heart
Cardiac tumors - benign
Lipomatous hypertrophy of cardiac intraatrial septum



Topic Completed: 1 November 2013

Revised: 1 March 2019

Copyright: 2007-2019, PathologyOutlines.com, Inc.

PubMed Search: Lipomatous hypertrophy of cardiac intra atrial septum


Nat Pernick, M.D.
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Cite this page: Pernick N Lipomatous hypertrophy of cardiac intraatrial septum. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/hearttumorlipomatoushypertrophy.html. Accessed June 19th, 2019.
Definition / general
  • Rare (0.6% of cardiac tumors); usually age 60+ years
  • Associated with increased epicardial fat (heart floats in water), mild to severe obesity
  • Symptoms include congestive heart failure, atrial fibrillation, supraventricular tachycardia, syncope, sudden unexpected cardiac death (Arch Pathol Lab Med 2006;130:397)
  • Often diagnosed at autopsy (Cesk Patol 2006;42:182)
  • "Hypertrophy" is a misnomer because mass is due to increased fat cells, not hypertrophied myocytes
Treatment
Gross description
  • Unencapsulated mass usually confined to atrium
  • Resembles brown fat
  • Associated with cardiac hypertrophy
  • Septal thickness is 2 to 7 cm (normal is < 1 cm)
  • Fossa ovalis is usually spared
Gross images
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Fatty deposit superior to fossa ovalis



Images hosted on other servers:
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Huge fatty tumor of atrial septum sparing fossa ovalis

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Tumor adjacent to epicardial fat

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Mixture of normal
fat, vesicular fat
and hypertrophied
myocytes
Microscopic (histologic) description
  • Multivacuolated fatty infiltration more than 2 cm thick in atrial septum
  • Cells have central nuclei without atypia
  • Some fat cells resemble brown fat and fat cells in malnourished patients
  • Usually atypical and hypertrophied myocytes (Am J Surg Pathol 1996;20:678)
  • Variable bands of collagen and chronic inflammatory infiltrates
  • No mitotic figures, no signet ring structures, no enlarged hyperchromatic and indented nuclei in fat cells
Microscopic (histologic) images
Missing Image Missing Image

Mixture of normal fat, vesicular fat and hypertrophied myocytes



Images hosted on other servers:
Missing Image

Mixture of normal
fat, vesicular fat
and hypertrophied
myocytes
Missing Image

Gross and micro images

Electron microscopy description
  • Abundant mitochondria in vesicular fat cells
Differential diagnosis
  • Lipoma: encapsulated, no muscle fibers
  • Liposarcoma: lipoblasts have large clear vacuoles and hyperchromatic indented nuclei
  • Myxoma: has stellate or globular cells, myxoid areas, no fat, no hypertrophied myocytes
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