Cardiac myxomas, although uncommon are one of the commonest primary cardiac tumours and account for ~50% primary benign cardiac tumours.
On this page:
Epidemiology
Cardiac myxomas are the most common primary cardiac tumour in adults (~50%) but are relatively infrequent in childhood, where cardiac rhabdomyomas are more frequent 8,11. The incidence of cardiac myxomas is approximately 0.5 per million population per year 12. There is a broad range in the age of presentation (11-82 years), with most patients presenting in adulthood (mean ~50 years of age) 7,13. There is a recognised female predilection 7,13.
Associations
An uncommon but well-described association with multiple endocrine neoplasia syndromes has been described, and is known as Carney complex 7,8.
Clinical presentation
Approximately 20% of patients are asymptomatic, with myxomas being found incidentally on imaging of the heart 7. Presumably, as the amount of imaging increases, so will this figure.
Clinical features are variable and depend on the location and other associated pathology, e.g. valve destruction. However, a triad of symptoms is recognised 7,8:
-
valvular obstruction
left sided: dyspnoea, orthopnoea, pulmonary oedema
right sided: symptoms of right heart failure
-
embolic event
distribution will depend on the location of the tumour
most are left sided, and, therefore, most are systemic (brain or extremities)
-
constitutional symptoms
weight loss, fatigue, weakness
may resemble infective endocarditis (fever, arthralgia, lethargy)
In ~20% of patients, arrhythmias may be identified 7.
On auscultation, a cardiac murmur is usually present. A characteristic finding in patients with pedunculated and prolapsing myxoma is the so-called "tumour plop" 7.
Pathology
Controversy exists in regards to the exact nature of these masses, but in general, they are considered benign neoplasms. Some authors believe that they represent organised thrombus.
Morphologically they are often haemorrhagic and are of variable firmness. They can be sessile or pedunculated (more common) and of variable size (1-10 cm). They most frequently arise in the left atrium, attached to the interatrial septum in the region of the fossa ovale.
Location
Patients with atrial myxomas can be divided into two groups: typical (vast majority) and atypical 7,9:
typical: solitary with ~75% located in the left atrium
atypical: earlier presentation; multiple tumours are common and are more frequently located in the right heart or left ventricle
Overall distribution 8,9:
-
atria (95%)
left (75%)
right (20%)
ventricles (5%)
Radiographic features
Plain radiograph
Chest radiographs can be normal 2. Abnormalities, if present, are non-specific and include:
intracardiac tumoural calcification
evidence of mitral valve obstruction
evidence of elevated left atrial pressure, e.g. pulmonary oedema
Ultrasound
Echocardiography is usually the initial modality used for identification and evaluation of cardiac myxomas. They appear as hyperechogenic lesions with a well-defined stalk. Moreover, echocardiography can be useful to assess the mobility of the tumour, as it often protrudes through valve flaps.
CT
Myxomas, as is the case with other cardiac tumours, appear as intracardiac masses, most often in the left atrium and attached to the interatrial septum. They are usually heterogeneously low attenuating (approximately two-thirds of cases 2,8). Due to repeated episodes of haemorrhage, dystrophic calcification is common 8. Calcification tends to be more common in right atrial myxoma 15.
If the mass is pedunculated, the motion within the heart can be demonstrated, including prolapse through the mitral valve.
MRI
MRI appearances are heterogeneous, reflecting the non-uniformity of these masses. They are typically spherical or ovoid masses which may be sessile or pedunculated 2,3.
T1: tend to be low to intermediate signal, but areas of haemorrhage may be high 3
T2: can be variable due to heterogeneity in tumour components, e.g. low signal calcific components; high signal myxomatous components
GRE: may show blooming of calcific components
T1 C+ (Gd): shows enhancement (important discriminator from a thrombus)
Treatment and prognosis
Complete resection in typical cases is usually curative with recurrence rates (either locally or elsewhere in the heart) reported in 0-5% of cases 11,14. In atypical cases or those with Carney complex, the rate is much higher (12-22%) 7,11.
Complications
cardiac arrhythmia(s)
embolic complications: e.g. stroke, haemorrhage from neoplastic intracranial aneurysm
Differential diagnosis
On imaging consider: