Makindo Medical Notes

Related Subjects: |Cardioembolic stroke |Ischaemic heart disease |Assessing Chest Pain

📖 About

• Incidence at autopsy ≈ 0.03%.
• Most common primary cardiac tumour, although metastatic tumours are more common overall.
• Usually benign and located in the left atrium (75%), commonly arising from the atrial septum near the fossa ovalis.
• Less commonly found in the right atrium or ventricles.
• First described in 1845 by King.

🧬 Genetics

• May occur as part of NAME syndrome (Nevi, Atrial myxoma, Myxoid neurofibroma, Ephelides) or LAMB syndrome (Lentigines, Atrial myxoma, Mucocutaneous myxoma, Blue nevi).
• Carney complex: Autosomal dominant, caused by mutations in the PRKAR1A gene. Associated with multiple myxomas, endocrine tumours, and lentigines.
• Sporadic myxomas are usually solitary; familial ones tend to be multiple, recurrent, and appear at younger age.

🩺 Pathology

• Typically a pedunculated gelatinous mass, attached by a stalk to the interatrial septum.
• Composed of stellate mesenchymal cells within a myxoid stroma.
• Mobility of the tumour allows intermittent obstruction of the mitral valve (“ball-valve effect”).
• IL-6 secretion may cause systemic inflammatory symptoms; IL-6 levels fall after resection.

⚠️ Clinical Features

• Classic triad:
  • 🧠 Embolic (≈35%): stroke, TIA, systemic emboli, retinal artery occlusion. Fragments may be tumour or thrombus (anticoagulation does not prevent this).
  • ❤️ Obstructive: mimics mitral stenosis – dyspnoea, orthopnoea, PND. “Tumour plop” (low-pitched early diastolic sound at apex, best with bell). Syncope or sudden death if severe obstruction.
  • 🌡️ Constitutional: fever, weight loss, myalgia, arthralgia, raised ESR/CRP, positive ANA/RF. Can mimic autoimmune disease.
• Positional variation: symptoms may worsen when upright or leaning forward due to tumour movement.
• Can present with sudden cardiac death if embolisation or valve obstruction is abrupt.

💡 Always consider atrial myxoma in patients with mitral stenosis–like symptoms + systemic features + embolic events.

🖼️ Images

• 📊 Bloods: normocytic anaemia, ↑ESR, ↑CRP, ↑IL-6, hypergammaglobulinaemia, ANA+ or RF+ (autoimmune mimic).
• 🫀 Echocardiography:
  • TTE: may miss up to 20% of cases.
  • TOE: gold standard – sensitivity ~100%, shows mobile mass with stalk, echolucent areas (haemorrhage/necrosis).
• 🧲 Cardiac MRI: defines size, site, attachment, tissue character → useful for surgical planning.
• 🩻 Coronary angiography: performed pre-op as tumour can have its own blood supply.
• Differentiation from atrial thrombus: thrombi are usually mural and immobile, while myxomas are pedunculated and mobile.

🌀 Complications

• Systemic emboli (esp. cerebral → stroke).
• Mitral regurgitation if valve damaged by tumour.
• Arrhythmias (AF, atrial flutter).
• Congestive cardiac failure due to obstruction.
• Sudden cardiac death.
• Recurrence (≈5% sporadic, higher in familial cases).

🛠️ Management

• ❌ No effective medical therapy.
• ✅ Definitive treatment is urgent surgical excision (due to embolic and obstructive risks).
• Excision often includes a portion of atrial septum; patch closure if required.
• All 4 chambers must be inspected for additional tumours.
• Mortality is low with early surgery; most patients make a full recovery.
• Follow-up: regular echocardiography (recurrence risk ~5%, but higher in familial Carney complex).

📚 References

• Atrial Myxoma – ResearchGate
• Atrial Myxoma Review – Circulation Research

Cases — Atrial Myxoma

• Case 1 — Embolic Presentation: A 42-year-old woman presents with sudden left-sided weakness. CT brain confirms an embolic stroke. Echocardiography reveals a mobile mass attached to the interatrial septum in the left atrium. Diagnosis: Left atrial myxoma presenting with systemic embolism.
• Case 2 — Obstructive/Cardiac Symptoms: A 55-year-old man reports exertional dyspnoea, orthopnoea, and recurrent presyncope. On exam, there is a diastolic “tumour plop” at the apex. Echo shows a pedunculated left atrial mass prolapsing into the mitral valve orifice during diastole. Diagnosis: Atrial myxoma causing functional mitral stenosis.
• Case 3 — Constitutional Symptoms: A 35-year-old woman presents with fever, weight loss, and arthralgia. Bloods: raised ESR and CRP, mild anaemia. Infective screen negative. Echocardiogram demonstrates a right atrial mass consistent with a myxoma. Diagnosis: Atrial myxoma presenting with systemic inflammatory features.

Teaching Commentary ❤️

Atrial myxomas are benign endocardial tumours, usually arising from the left atrium (≈75%), attached to the fossa ovalis region. Clinical presentations fall into the triad of: 1. Embolic phenomena (strokes, peripheral emboli), 2. Obstructive symptoms (mimicking mitral stenosis), 3. Constitutional features (fever, weight loss, raised ESR/CRP). Echo (transthoracic or transoesophageal) is diagnostic. Definitive treatment is surgical excision, as tumours are friable and embolic risk is high. Recurrence is rare but more likely in familial cases (Carney complex).