Atrial Myxoma

• Primary tumours of heart are rare
• Most common type of primary tumour of the heart [>50%] are myxomas
• Benign
• 86% occur in left atrium [rarer in right atrium & much rarer in ventricles]
• Over 90% are solitary
• Arise from endocardium
• In left atrium: usual site of attachment is fossa ovalis (ie interatrial septum)
• Most common between ages of 30-60 years
• More frequent in females
• may be transmitted in an autosomal dominant manner

Pathology

• Often develop in region of fossa ovalis
• Often have a thin pedicle
• Tumour may be small like a bean but may grow into a large, smooth, ball-like or villous object filling the left atrium almost entirely but leaving the rest of the endocardium & myocardium almost unchanged
• On a cut surface the myxoma is gelatinous, often with patchy haemorrhagic areas
• average 4-8 cm in diameter

Clinical complications of myxoma

• The specific signs & symptoms produced by tumours are more closely related to their specific anatomical location than to their histological types

left atrial tumours

A) Mitral valve disease

• Mobile, pedunculated left atrial tumours may prolapse to various degrees into the mitral valve orifice resulting in obstruction to AV blood outflow and frequently mitral regurgitation —> resultant signs & symptoms mimic mitral valve disease especially mitral stenosis :dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea, acute pulmonary oedema, cough, hemoptysis, chest pain, peripheral oedema, fatigue

§ However, may also see S & S not commonly seen in mitral valve disease: weight loss, pallor, syncope, sudden death

• Symptoms may be sudden on onset, intermittent and related to body position
• May see sudden loss of consciousness because of obstruction of the flow of blood through the heart
• Although the majority of symptoms are non specific, the occurrence of paroxysmal symptoms that arise characteristically in a particular body position raise the possibility of a left atrial tumour [when tumour is obstructing mitral valve]

B) Embolisation

• Myxomas are the source of most tumour emboli because of their combination of their friable consistency and intracavitary location
• Left-sided tumours tend to embolize to the systemic circulation resulting in infarction and haemorrhage of viscera, heart, limbs and vascular aneurysms
• Multiple emboli may mimic systemic vasculitis or infective endocarditis
• Neurological consequences of embolization include TIAs, seizures, syncope, and cerebral, cerebellar, brain stem, spinal cord and retinal infarctions