Atrial Myxoma

Content of This Page

1- Introduction

2- Causes

3- Symptoms

4- Stages of The Disease

5- Treatment

6- What Should You Avoid

Introduction

Atrial Myxoma is the most common primary cardiac tumor, typically benign in nature. It most frequently arises in the left atrium and is often attached to the interatrial septum, usually at the region of the fossa ovalis.

Although histologically benign, atrial myxomas can have serious clinical consequences due to their location and potential to obstruct intracardiac blood flow or embolize systemically. The clinical presentation is variable and can mimic other cardiac diseases, leading to diagnostic challenges.

Myxomas are more common in females and usually occur in middle age, though familial forms can occur at a younger age and may be part of Carney complex (a syndrome associated with multiple tumors and skin pigmentation)

© image from Wikimedia Commons

Causes

  • Sporadic (most common): Occurs without family history or syndromic association.

  • Familial or syndromic (rare): May occur in the context of Carney complex

Therefore, the cause is typically unknown (idiopathic), but some are:

  • Possibly related to genetic mutations (when familial)

  • Related to embryonic rests or pluripotent mesenchymal cell growths

Symptoms

1. Obstructive Symptoms

Caused by the tumour partially or completely blocking blood flow through the mitral valve, especially if pedunculated (on a stalk):

  • Exertional dyspnoea (shortness of breath)

  • Orthopnoea (breathlessness lying flat)

  • Paroxysmal nocturnal dyspnoea (waking breathless at night)

  • Syncope or sudden death (rare; due to complete mitral obstruction)

  • Mimics mitral stenosis:

    • Loud first heart sound (S1)

    • Low-pitched mid-diastolic murmur

    • “Tumor plop” early diastolic sound (classic finding)

 

2. Embolic Symptoms

Fragments of the tumour or thrombus on its surface can embolize:

  • Stroke (especially in younger patients without other risk factors)

  • Retinal artery occlusion → sudden visual loss

  • Peripheral embolism → limb ischaemia

  • Renal or mesenteric infarction (rare)

3. Constitutional Symptoms

Due to release of interleukin-6 (IL-6) or tumor necrosis:

    • Fever

    • Malaise

    • Weight loss

    • Clubbing (rare)

    • Arthralgia (joint pain)

    • Raised ESR/CRP, mimicking autoimmune or infective endocarditis

© image from librepathology

Stages of The Disease

1. Silent (Asymptomatic) Phase

  • The tumour is small and often discovered incidentally on echocardiography.

  • No significant obstruction or embolic potential.

  • No systemic or constitutional symptoms.

2. Prodromal (Constitutional) Phase

  • The tumour begins secreting cytokines such as interleukin-6 (IL-6).

  • Symptoms include:

    • Low-grade fever

    • Fatigue and malaise

    • Weight loss

    • Raised inflammatory markers (e.g. ESR, CRP)

3. Obstructive/Mechanical Phase

  • As the tumour enlarges, it intermittently obstructs the mitral valve (especially in the left atrium).

  • Symptoms:

    • Exertional dyspnoea

    • Orthopnoea and paroxysmal nocturnal dyspnoea (PND)

    • Syncope, particularly with changes in posture

  • Auscultatory findings:

    • Variable mid-diastolic murmur

    • “Tumour plop” sound (early diastole)

4. Embolic Phase

  • Surface thrombi or friable tumour fragments break off.

  • Embolic events may involve:

    • Brain (stroke, transient ischaemic attacks)

    • Retina (sudden visual loss)

    • Limbs (acute ischaemia)

    • Organs such as kidneys or intestines (infarctions)

5. Complicated Phase

  • Can result in:

    • Acute pulmonary oedema or heart failure

    • Sudden cardiac death due to complete mitral valve obstruction

    • Pulmonary hypertension if mitral obstruction is prolonged

Treatment

  • Surgical Excision:

    • Open-heart surgery under cardiopulmonary bypass is required.

    • Complete resection is important to prevent recurrence.

    • The attachment site (often the interatrial septum) is usually resected or repaired to ensure no residual tumor remains.

  • Postoperative Follow-up:

    • Echocardiographic surveillance is necessary to monitor for recurrence, especially in patients with familial or syndromic forms (e.g. Carney complex).

    • Recurrence is rare in sporadic cases (<5%) but higher in familial cases.

  • Management of Complications:

    • Embolic complications (e.g., stroke) are managed supportively but do not delay surgery unless absolutely necessary.

    • If associated with constitutional symptoms, these typically resolve after tumor removal.

  • Family Screening:

    • In suspected familial cases (e.g., Carney complex), genetic counselling and screening of first-degree relatives may be indicated.

What Should You Avoid

  • Avoid delaying echocardiography in patients with unexplained stroke, fever, or dyspnoea.

  • Avoid strenuous physical activity in symptomatic patients (e.g. syncope or positional breathlessness).

  • Avoid misdiagnosing as endocarditis or autoimmune disease—fever and raised ESR can mislead.

  • Avoid anticoagulation unless thrombus is confirmed—surgery is the treatment of choice.

  • Avoid postponing surgery—even asymptomatic tumours carry risk of embolism or obstruction.

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