Myxomas are benign, usually pedunculated tumors that usually arise
from the atrial septum near the foramen ovale; occasionally, they attach elsewhere
in the atria or the ventricles. They are more common in the left than
the right atrium and can even be biatrial. Atrial myxomas may simulate
mitral or tricuspid valve disease because they often prolapse into
the valve ring to produce obstruction or regurgitation; chest pain,
dyspnea, or syncope may result. They frequently embolize to systemic
or pulmonary arteries or obstruct pulmonary veins. They may be associated
with fever, weight loss, myalgia, anorexia, Raynaud syndrome, as
well as increases in sedimentation rate, γ-globulins,
and serum antihyaluronidase titers. These systemic symptoms result
from release of cytokines, especially interleukin-6, and often lead
to misdiagnosis of collagen vascular disease or infective endocarditis.
The diagnosis may be suspected clinically, especially if the mitral
or tricuspid murmurs change from time to time or with differences
of position. Surgical removal is usually successful,
except that recurrences often occur in the familial types. About
5% of myxomas are familial or associated with cutaneous
or endocrine syndromes. The Carney complex is an autosomal dominant mutation
associated with alterations of the PRKAR1A gene
on chromosome 17 in some patients. The syndrome includes skin pigmentation
(lentigenes, blue nevi), myxoma, primary pigmented nodular adrenocortical disease,
Sertoli cell tumors, and acromegaly