Atrial myxoma - Cardiovascular oncology

Cardiovascular oncology

Atrial myxoma

Definition

An atrial myxoma is a benign primary tumour of the heart most commonly arising in the left atrium.

Incidence

Primary tumours of the heart are rare, but atrial myxoma is the most common.

Aetiology

The aetiology of atrial myxoma is unknown.

Pathophysiology

The tumour is usually located on a pedicle arising from the atrial septum, and can grow up to about 8 cm across. The pedicle allows the tumour to move within the atrium resulting in various symptom complexes. If the tumour obstructs the mitral valve a picture similar to mitral stenosis will occur. If the tumour passes through the mitral valve, mitral regurgitation will occur. Complete mitral valve obstruction may cause syncope. The tumour may also give rise to thrombosis due to altered flow patterns and resultant systemic embolisation. Local invasion and distant metastasis do not occur.

Clinical features

The clinical picture varies but the diagnosis is suggested by features of mitral stenosis with variable cardiac murmurs and a loud first heart sound especially if coupled to a fever. Many patients have a ‘tumour plop’ in early diastole. Thromboembolism may result from the abnormal flow pattern through the atrium. It occurs in 40% and is a common presenting feature.

Investigations

ESR is usually raised. Echocardiography demonstrates the mass lesion within the atrium.

Macroscopy

The tumour is usually a polypoid mass on a stalk, its surface covered with thrombus. Histologically the tumour is made up of connective tissue, with a variety of cell types surrounded by extracellular matrix.

Management

The tumour is surgically removed under cardiopulmonary bypass.

Prognosis

Five per cent local recurrence within 5 years. Followup with regular echocardiography is therefore indicated even in asymptomatic patients.