atrial myxoma

Introduction

Most common primary cardiac tumor.

Etiology

• sporadic
• associated with NAME or LAMB syndrome

Epidemiology

• sporadic form
  • 39-82 years; mean age: 56 years
  • female/male ratio 2.7/1
• associated with NAME syndrome or LAMB syndrome
  • 10-56 years; mean age: 25 years
  • female/male ratio 1.8/1

Pathology

• location:
  • left atrium 75%
  • right atrium 18%
  • most arise from atrial septum (fossa ovalis)
• most myxomas have a short stalk, are gelatinous & friable, & tend to embolize
• left atrial tumors prolapse into the mitral valve & cause mitral stenosis
• occasionally calcify
• systemic emboli occur in 30-60% of patients with left-sided myxoma, frequently to brain & lower extremities
• sporadic form: 99% have single myxoma
• associated with NAME syndrome or LAMB syndrome
  • 50% have multiple myxomas
  • 57% with non-cardiac tumors
  • 30% with associated endocrine tumor
  • 13% with ventricular myxoma

Genetics

• associated with NAME syndrome or LAMB syndrome
  • 14% autosomal dominant
• associated with defects in PRKAR1A gene (autosomal recessive)

Clinical manifestations

• obstruction to blood flow
• embolization
• systemic effects
  • fatigue/malaise
  • fever
  • progressive dyspnea
  • orthopnea
  • weight loss
  • arthralgia
  • clubbing
• symptoms occur with changes in body position
• an early diastolic sound or tumor plop may be heard
• soft-mid diastolic murmur best heard at the cardiac apex
  • may change with changes in body position
• autosomal dominant form (NAME syndrome or LAMB syndrome)
  • 68% with associated freckles
• cardiac arrhythmias are uncommon

Laboratory

• histologic examination of embolized material
• with systemic manifestations
  • ESR: elevated ESR
  • complete blood count: leukocytosis
  • protein electrophoresis: hypergammaglobulinemia (IgG)

Radiology

• calcified myxomas may be visible on chest X-ray
• echocardiogram

Complications

• systemic embolism, embolic stroke
• sudden death

Differential diagnosis

• diastolic murmur similar to mitral stenosis
  • mitral valve endocarditis associated with mitral regurgitation
• marantic endocarditis
  • signs & symptoms of systemic embolization
  • rarely murmurs

Management

• surgery
• left atrial myxoma should be removed even if patient is asymptomatic to avoid systemic embolism, embolic stroke
• myxomas may be recurrent, thus periodic long-term follow-up is indicated

More general terms

• cardiac myxoma

Additional terms

• LAMB syndrome
• NAME syndrome