Cardiology > Atrial Myxoma

Background 

Atrial myxoma is the most common primary benign cardiac tumor, typically arising from the interatrial septum in the region of the fossa ovalis, usually within the left atrium. Composed of myxoid (gelatinous) tissue, myxomas are pedunculated and can prolapse into the mitral valve orifice, mimicking mitral stenosis or causing embolic phenomena. Though benign, atrial myxomas can be life-threatening due to obstructive and embolic complications. 

II) Classification/Types 

By Location: 

• • Left atrial myxoma (80%) – Attached to the fossa ovalis; most symptomatic 
  • Right atrial myxoma (15–20%) – May mimic tricuspid valve disease 
  • Ventricular myxoma (rare) – Associated with worse hemodynamic compromise 

By Morphology: 

• • • Pedunculated: Most common; mobile mass with stalk 
    • Sessile: Broad-based and less mobile 

By Clinical Pattern: 

• • • Sporadic: Most cases, typically in middle-aged females 
    • Familial: Autosomal dominant (Carney complex), younger age, multiple or recurrent tumors 

Pathophysiology 

Atrial myxomas obstruct blood flow by prolapsing through the mitral or tricuspid valve during diastole, causing symptoms similar to valve stenosis. Fragments may embolize to the brain, limbs, or other organs. Additionally, myxomas can secrete inflammatory cytokines (e.g., interleukin-6), causing systemic constitutional symptoms like fever and malaise. Their gelatinous, friable nature predisposes to embolization. 

Epidemiology 

• • Atrial myxomas account for ~50% of primary cardiac tumors in adults 
  • Predominantly occur in women aged 30–60 years 
  • Sporadic cases are more common than familial 
  • Familial cases are associated with Carney complex and may present earlier with multiple lesions 

Etiology 

I) Causes 

• • Sporadic mutation in endocardial mesenchymal cells 
  • Familial cases: Associated with Carney complex (PRKAR1A gene mutation), which may include lentigines, endocrine tumors, and schwannomas 

II) Risk Factors 

• • Positive family history (Carney complex) 
  • Female sex 
  • Age 30–60 for sporadic cases 
  • Childhood and adolescence in familial forms 

Clinical Presentation 

I) History (Symptoms) 

• • Dyspnea, orthopnea: From mitral valve obstruction 
  • Syncope or presyncope: Intermittent obstruction of mitral inflow 
  • Palpitations or chest pain 
  • Embolic events: Stroke, limb ischemia, retinal artery occlusion 
  • Systemic symptoms: Fever, weight loss, malaise from cytokine release 

II) Physical Exam (Signs) 

• • Diastolic murmur at apex that changes with position 
  • “Tumor plop” sound: Early diastolic sound heard best in left lateral position 
  • Signs of systemic embolization: Focal neurologic deficits, skin changes 
  • Features of heart failure in severe obstruction 

Differential Diagnosis (DDx) 

• • Mitral stenosis (rheumatic or congenital) 
  • Intracardiac thrombus 
  • Infective endocarditis 
  • Cardiac metastases or other tumors 
  • Atrial septal aneurysm 
  • Left atrial ball thrombus (in AF) 

Diagnostic Tests 

Initial Evaluation 

• • ECG: Nonspecific; may show left atrial enlargement or atrial arrhythmias 
  • Chest X-ray: May show cardiomegaly or pulmonary edema 
  • Transthoracic echocardiography (TTE): First-line imaging; identifies size, mobility, and location 
  • Transesophageal echocardiography (TEE): Superior for defining attachment site, mobility, and tumor features 

Advanced Imaging 

• • Cardiac MRI or CT: Used for tissue characterization, differentiating thrombus from tumor, preoperative planning 
  • Histopathology: Confirmatory; surgical resection specimen shows stellate or polygonal myxoma cells in myxoid stroma 
  • ESR/CRP/IL-6: May be elevated due to cytokine production 

Treatment 

I) Acute Management 

• • Hospital admission for symptomatic or embolic myxoma 
  • Stabilize cardiac function if signs of heart failure 
  • Anticoagulation if embolic risk present, although surgery is definitive 

II) Chronic Management 

• • Surgical excision is the treatment of choice and should be performed promptly due to risk of embolization or sudden death 
  • Repair of atrial septal defect often needed after excision 
  • Monitor for recurrence, especially in familial cases 

Medications 

Device Therapy 

• • No specific device therapy unless complications (e.g., arrhythmias requiring pacemaker) 
  • TEE or MRI surveillance devices used during long-term follow-up 

Patient Education, Screening, Vaccines 

• • Educate on signs of recurrence (dyspnea, stroke-like symptoms) 
  • Familial screening if Carney complex suspected 
  • Encourage early medical evaluation for new symptoms 
  • Influenza and pneumococcal vaccines if heart failure is present 

Consults/Referrals 

• • Cardiothoracic surgery: For tumor resection 
  • Cardiology: For workup and follow-up of structural effects 
  • Neurology: For embolic complications (e.g., stroke) 
  • Genetics: If Carney complex or multiple tumors present 

Follow-Up 

Short-Term 

• • Post-op monitoring for arrhythmias, infection, or pericardial effusion 
  • Echocardiography before discharge and at 1–3 months 

Long-Term 

• • Annual TTE or MRI to monitor for recurrence 
  • Family screening in hereditary cases 
  • Monitor for embolic complications, especially if patient delays surgery 

Prognosis 

• • Excellent after complete surgical resection in sporadic cases (recurrence <5%) 
  • Higher recurrence risk in familial myxomas or incomplete excision 
  • Sudden death risk if untreated due to embolism or obstruction 
  • Prompt diagnosis and surgery ensure near-total resolution of symptoms and prevent complications 
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