Atrial Myxoma

• Barry Fine, M.D., PH.D.

 Basic Information

Definition

Atrial myxoma is a benign neoplasm of mesenchymal origin and is the most common primary tumor of the heart.

Synonyms

1. Cardiac myxoma

ICD-10CM CODES
D15.1	Benign neoplasm of heart

Epidemiology & Demographics

1. •

   Primary cardiac tumors are extremely rare, with an autopsy frequency of 0.001% to 0.3%. The most frequent cardiac tumors are metastases, occurring 30 times more frequently than primary tumors.

2. •

   Myxomas are the most common primary cardiac tumors, accounting for 30% to 50% of all benign neoplasms of the heart.

3. •

   65% of cardiac myxomas occur in females. 4.5% to 10% of cardiac myxomas are familial (Carney syndrome).

4. •

   Median age of incidence is 49 yr but can occur at any age.

5. •

   Average age of incidence of familial cases is 25 yr.

6. •

   Most arise in the left atrium (75%), but myxomas can also be found in the right atrium (18%), right ventricle (4%), and left ventricle (3%). They are usually pedunculated and attached to the intra-atrial septum.

Physical Findings & Clinical Presentation

Patients with atrial myxomas, when symptomatic, characteristically present in one of three ways:

1. 1.

   Atrioventricular valve obstruction (e.g., mitral or tricuspid valve): may present with dyspnea, orthopnea, paroxysmal nocturnal dyspnea, wheezing, edema, dizziness, syncope, chest pain, atrial fibrillation, and sudden death (rare). A marked change in the severity of any symptom caused by a change in position of the patient, especially if recumbency relieves dyspnea, is suggestive of myxoma.

2. 2.

   Systemic embolization: leading to cerebrovascular accidents, pulmonary embolism, paradoxical embolism and acute coronary syndrome. This is present in 29% of patients with atrial myxomas.

3. 3.

   Constitutional symptoms: fever, weight loss, arthralgias and Raynaud’s phenomenon.

4. 4.

   Other rare manifestations include peripheral neuropathy, typical angina caused by coronary steal phenomenon (especially large vascularized atrial myxomas), and paraneoplastic syndromes.

On exam there may be widely split loud S1, secondary pulmonary hypertension, murmurs of regurgitation (holosystolic) or stenosis (rumbles), an early diastolic sound 80-120 milliseconds after A2 called “tumor plop” which may resemble an opening snap.

Etiology

1. •

   Most cases (90%) of atrial myxomas are sporadic with no known cause.

2. •

   Carney complex, transmitted in an autosomal dominant pattern, accounts for the majority of familial myxomas and as much as 7% of cardiac myxomas. Carney syndrome manifests as cardiac and extracardiac myxomas, pigmented skin discoloration, endocrine hyperactivity, and other tumors, such as schwannomas. There are at least three different genetic loci with two identified genes for this complex.

Diagnosis

Differential Diagnosis

1. •

   Primary valvular diseases: mitral stenosis, mitral regurgitation, tricuspid stenosis, tricuspid regurgitation

2. •

   Pulmonary hypertension

3. •

   Endocarditis

4. •

   Vasculitis

5. •

   Atrial thrombus

6. •

   Pulmonary embolism

7. •

   Cerebrovascular accidents

8. •

   Collagen-vascular disease

9. •

   Carcinoid heart disease

10. •

    Benign tumors of the heart (papillary fibroelastoma, rhabdomyoma, fibroma, teratoma, and lipoma)

11. •

    Malignant tumors of the heart (angiosarcoma, rhabdosarcoma, fibrosarcoma, and leiomyosarcoma)

12. •

    Metastatic tumors to the heart (melanoma, lung, breast, renal, esophageal, and sarcomas)

Workup

A high index of suspicion is needed because the clinical manifestations are nonspecific and similar to many common cardiovascular and pulmonary diseases.

Laboratory Tests

Although not very specific, the following laboratory findings may be abnormal in patients with atrial myxomas:

1. •

   Complete blood count: anemia, polycythemia, thrombocytopenia may occur

2. •

   Erythrocyte sedimentation rate, C-reactive protein, and serum immunoglobulins are commonly elevated

3. •

   Cardiac biomarker levels (troponin and CK-MB) can be elevated

4. •

   Electrocardiogram: nonspecific findings including left or right atrial enlargement, atrial fibrillation, premature ventricular depolarizations, or ventricular tachycardia

Imaging Studies

1. •

   Transthoracic echocardiography (Fig. 1): With 95% diagnostic sensitivity, it is the initial test of choice in suspected cases of atrial myxoma.

   

2. •

   Chest radiograph: about one third of patients have normal findings. Evidence of altered cardiac contour, pulmonary edema, and chamber enlargement may be present.

3. •

   Transesophageal echocardiography: nearly 100% sensitive and may better define cardiac masses not clearly visualized by transthoracic echocardiography.

4. •

   CT: often used for diagnosis; defines tumor extension and evaluates adjacent cardiac structures.

5. •

   MRI (Fig. 1): delineates size, shape, and tissue characteristics, helping distinguish thrombus from tumor.

6. •

   Cardiac catheterization: will show neovascularization in 50% of the cases and may be required to rule out concomitant coronary artery disease in anticipation of surgical excision.

Treatment

Acute General Therapy

1. •

   Surgical excision is the treatment of choice.

2. •

   Surgery should be done promptly because systemic embolization and/or sudden death can occur while waiting for the procedure.

Chronic Rx

Postoperative arrhythmias and conduction abnormalities were present in 26% of patients and can be treated accordingly.

Disposition

1. •

   Surgical results have reported a 95% survival rate after a follow-up of 3 yr.

2. •

   Careful follow-up is necessary because up to 5% of sporadic cases and 20% of familial cases of atrial myxoma may recur within the first 6 yr after surgery. A family history of myxomas, atypical location and multicentric features are risk factors for myxoma recurrence after resection.

3. •

   Sudden death in untreated patients may occur in up to 15%, resulting from coronary or systemic embolization or obstruction of the mitral or tricuspid valve.

Referral

1. •

   Consultation with a cardiologist is recommended.

2. •

   Once the presence of cardiac tumor is confirmed, consultation with a cardiovascular surgeon is needed for prompt surgical excision.

Pearls & Considerations

1. •

   Approximately two thirds of patients present with cardiovascular symptoms, specifically dyspnea, often suggestive of valvular obstruction.

2. •

   Nearly one third of patients have evidence of systemic embolization.

Comments

Annual echocardiograms should be performed to monitor for recurrence of atrial myxomas after surgical excision.

Related Content

1. Atrial Myxoma (Patient Information)