An atrial myxoma is a noncancerous tumor in the upper left or right side of the heart. It most often grows on the wall that separates the two sides of the heart. This wall is called the atrial septum.
A myxoma is a primary heart (cardiac) tumor. This means that the tumor started within the heart. Most heart tumors start somewhere else.
Primary cardiac tumors are rare. Myxomas are the most common type of these rare tumors. About 75% of myxomas occur in the left atrium of the heart. They most often begin in the wall that divides the two upper chambers of the heart. The rest are in the right atrium. Right atrial myxomas are sometimes linked with tricuspid stenosis and atrial fibrillation.
Myxomas are more common in women. About 1 in 10 myxomas are passed down through families (inherited). These tumors are called familial myxomas. They tend to occur in more than one part of the heart at a time, and often cause symptoms at a younger age.
Symptoms may occur at any time, but most often they go along with a change in body position.
Surgery is needed to remove the tumor. Some people will also need the mitral valve replaced. This can be done during the same surgery.
Myxomas may come back if surgery does not remove all of the tumor cells.
A myxoma is not cancer, but complications are common.
Untreated, a myxoma can lead to an embolism (tumor cells breaking off and traveling in the bloodstream). This can lead to a blockage of blood flow or cause the tumor to grow in another part of the body. Pieces of the tumor can move to the brain, eye, or limbs.
If the tumor grows inside the heart, it can block blood flow. This may require emergency surgery to prevent sudden death.
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McKenna W. Diseases of the myocardium and endocardium. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 60.
Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.