Cardiac myxoma is the most common primary benign cardiac tumor, accounting for approximately 50% of all primary heart tumors. About 75-80% of myxomas arise in the left atrium, typically attached to the interatrial septum at the fossa ovalis. Grossly, the tumor has a gelatinous, lobulated, and heterogeneous appearance, usually connected to the atrial septum by a stalk (pedicle). Its mobility can cause mitral valve obstruction leading to syncope and sudden death — the so-called 'wrecking ball' effect. Besides sporadic cases, myxomas may occur as part of the Carney complex, an autosomal dominant syndrome featuring multiple myxomas, skin pigmentation, and endocrine tumors. Embolic complications (stroke, peripheral embolism) are reported in 30-40% of patients at diagnosis.
Age Range
30-60
Peak Age
50
Gender
Female predominant
Prevalence
Uncommon
Cardiac myxoma arises from multipotent mesenchymal cells (subendocardial reserve cells of the endocardium) that proliferate within a myxoid stroma. The gelatinous matrix is rich in glycosaminoglycans and hyaluronic acid; this mucopolysaccharide-rich composition translates to marked T2-weighted hyperintensity on MRI and low-to-intermediate density on CT. Intratumoral hemorrhage, calcification, cystic degeneration, and hemosiderin deposition are frequent, creating a heterogeneous signal/density pattern across all modalities. The pedunculated attachment allows the tumor to move with the cardiac cycle; during diastole it prolapses into the mitral orifice creating the 'wrecking ball' effect, which can be demonstrated in real-time on echocardiography. The fragile surface tissue and papillary projections predispose to fragmentation and overlying thrombus detachment, causing systemic embolization (particularly cerebral). Post-contrast heterogeneous enhancement reflects tumor neovascularity and central avascular zones.
The echocardiographic finding of the pedunculated left atrial myxoma demonstrating a 'swinging' motion as it prolapses through the mitral valve orifice during diastole. This dynamic motion forms the basis of obstructive symptoms (syncope, dyspnea) and potential embolic complications. It is a pathognomonic finding; such pronounced mobility is not seen in other intracardiac masses.
On transthoracic echocardiography (TTE), a round or lobulated, heterogeneously echogenic mass in the left atrium attached to the interatrial septum by a stalk. During diastole, it prolapses through the mitral valve orifice ('wrecking ball' motion) and returns to the atrium in systole. Tumor size typically ranges from 2-8 cm.
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A heterogeneously echogenic mobile mass measuring approximately _x_ cm is seen in the left atrium, attached to the interatrial septum by a stalk, prolapsing through the mitral orifice during diastole.
Color Doppler demonstrates turbulent flow pattern and increased transmitral gradient during the period when the tumor prolapses into the mitral orifice. Pulsed-wave Doppler shows altered diastolic filling pattern (increased E-wave, diastolic pressure gradient). In severe obstruction, systolic-diastolic reversal of pulmonary venous flow pattern may be observed.
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Color Doppler demonstrates turbulent flow at the mitral valve level with increased transmitral gradient (mean _x_ mmHg) during tumor prolapse.
On non-contrast CT, a low-to-intermediate density (approximately 20-40 HU), lobulated, well-circumscribed intracavitary mass in the left atrium. Punctate or coarse calcifications are frequently seen within the tumor (up to 50%). Gelatinous components show water-to-soft tissue density. Acute hemorrhage areas may be identified as high-density foci.
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An intracavitary mass of low-to-intermediate density (approximately _x_ HU) with lobulated contour measuring _x_ cm is seen in the left atrium originating from the interatrial septum. Punctate calcifications are present within the mass.
On contrast-enhanced cardiac-gated CT, the tumor shows heterogeneous enhancement. More prominent enhancement is seen in peripheral areas, while central regions show hypodense areas (necrosis, cystic degeneration, or mucoid material). The density difference between the tumor stalk and intracavitary blood pool clarifies mass boundaries. ECG-gated CT minimizes motion artifact, optimally evaluating tumor morphology and relationship to the mitral valve.
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On contrast-enhanced ECG-gated CT, the left atrial mass shows heterogeneous enhancement with central hypodense areas and peripheral enhancement.
On T1-weighted sequences, myxoma shows iso-to-hypointense heterogeneous signal relative to myocardium. Subacute hemorrhage areas are identified as focal hyperintense foci (methemoglobin effect). Gelatinous matrix components predominantly appear isointense. Low signal foci may be seen in areas of hemosiderin deposition.
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On T1-weighted sequences, the left atrial mass shows iso-to-hypointense heterogeneous signal relative to myocardium with focal hyperintense foci consistent with subacute hemorrhage.
On T2-weighted sequences, myxoma characteristically shows markedly hyperintense signal — this finding reflects the high water and mucopolysaccharide content of the gelatinous matrix and is the most distinguishing MR feature for diagnosis. Hyperintensity is prominent even in solid components of the tumor. Low signal foci ('blooming') may be seen in areas containing hemorrhage or calcification. Signal becomes even more conspicuous on T2 STIR sequences.
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On T2-weighted sequences, the left atrial mass shows markedly hyperintense signal reflecting high mucopolysaccharide content.
On late gadolinium enhancement (LGE) sequences, myxoma shows a heterogeneous enhancement pattern. Enhancement is prominent in peripheral and vascularized areas, while central mucoid or necrotic areas show no enhancement. The tumor stalk typically enhances intensely. This pattern differs from the diffuse-aggressive enhancement pattern of malignant tumors (sarcomas). Absence of enhancement in myocardium surrounding the tumor confirms lack of invasion.
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On LGE sequences, the left atrial mass shows heterogeneous enhancement with intense enhancement at the stalk and minimal enhancement centrally. No pathological enhancement is identified in surrounding myocardium.
On cine SSFP (balanced steady-state free precession) sequences, the dynamic motion of myxoma is demonstrated with high temporal resolution. During diastole, the tumor prolapses toward the mitral valve orifice and returns to the atrial roof in systole. Tumor morphology, stalk length, and relationship to the mitral valve are best evaluated on this sequence. Motion restriction of mitral valve leaflets due to the tumor can also be dynamically observed.
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On cine SSFP sequences, the left atrial mass demonstrates characteristic mobile motion with diastolic prolapse into the mitral orifice. Stalk length measures approximately _x_ cm.
On FDG PET-CT, myxoma typically shows low-to-moderate FDG uptake (SUVmax 2-5). This uptake is significantly lower than the aggressive FDG uptake of malignant cardiac tumors (sarcomas, lymphoma) (SUVmax >8-10). However, focal increased uptake may be observed in areas of inflammation or high cellularity. PET-CT is useful for evaluating concurrent embolic complications (cerebral, peripheral) and distant metastatic disease (for malignant tumor exclusion).
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On FDG PET-CT, the left atrial mass shows low-to-moderate metabolic activity (SUVmax: _x_), without high metabolic activity suggestive of malignant tumor.
Criteria
Accounts for 93-95% of all myxoma cases. Single lesion, usually left atrium, age 40-70 years, 2-3 times more common in females. Carney complex criteria not met. Recurrence rate 1-3% after surgery.
Distinct Features
Single, large (average 5-6 cm), left atrial, pedunculated mass. Female predominance. Low recurrence risk.
Criteria
Autosomal dominant inheritance (PRKAR1A gene mutation). Multiple myxomas (50%), atypical locations (right atrium, ventricular), young age onset (<30 years). Associated skin lentigines, cutaneous myxomas, adrenal nodular hyperplasia, pituitary adenoma, schwannoma.
Distinct Features
Young age, multiple/recurrent myxomas, atypical location, systemic syndrome features. Recurrence rate 20-25% after surgery (high). Genetic testing (PRKAR1A) and family screening mandatory.
Criteria
Papillary/villous projections dominant on myxoma surface. More fragile structure, higher embolic complication risk. Surface irregularity may create 'jellyfish' appearance on echocardiography.
Distinct Features
High embolic risk, fragile surface, irregular contour. Myxoma fragments may be detected histopathologically in embolectomy specimens. Pre-surgical embolism prophylaxis critical.
Criteria
Accounts for 15-20% of all myxoma cases. May cause tricuspid valve obstruction. Pulmonary embolism risk (instead of systemic embolism). Right heart failure symptoms predominant.
Distinct Features
Mass in right atrium, pulmonary embolism presentation, right heart failure. Carney complex should be considered. Relationship with inferior/superior vena cava should be evaluated.
Distinguishing Feature
Thrombus is typically T2 hypointense (hemoglobin degradation products), shows no enhancement, is broad-based (not pedunculated), and adheres to the left atrial appendage or akinetic/dyskinetic segments. Myxoma is T2 hyperintense, shows heterogeneous enhancement, and is located at the fossa ovalis.
Distinguishing Feature
Angiosarcoma is more common in the right atrium, broad-based, infiltrative, and invades the pericardium. Shows aggressive enhancement and hemorrhagic T1 hyperintensity. High FDG uptake on PET (SUVmax >8). Myxoma is in the left atrium, pedunculated, non-invasive, and shows low metabolic activity.
Distinguishing Feature
Papillary fibroelastoma is typically on the valve (<1.5 cm), 'sea anemone' appearance, small and homogeneous. Myxoma is much larger (2-8 cm), attached to the atrial septum, and has heterogeneous internal structure.
Distinguishing Feature
Metastatic tumors are typically multiple, myocardial/epicardial, with pericardial extension and known primary malignancy history. Myxoma is single, intracavitary, septum-attached, and without primary malignancy history.
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
annualCardiac myxoma is an urgent surgical indication due to risk of embolic complications (stroke, peripheral ischemia) and hemodynamic obstruction (syncope, sudden death). Treatment is open-heart surgery via sternotomy with resection of the tumor along with the stalk and a portion of the interatrial septum, with patch repair if needed. Surgical mortality is 1-3%. Recurrence rate is 1-3% in sporadic cases and 20-25% in Carney complex. Annual echocardiographic follow-up for recurrence is recommended post-surgery. PRKAR1A genetic testing and first-degree relative screening should be performed when Carney complex is suspected.
Cardiac myxoma is treated with surgical resection and prognosis is excellent — recurrence rate is below 5% in sporadic cases. Urgent surgical indication exists because the risk of embolization is high (systemic emboli in 30-45% of cases). In suspected Carney complex (multiple/recurrent myxomas, young age, family history), PRKAR1A gene mutation should be screened and regular cardiac imaging follow-up should be planned. Postoperative echocardiographic follow-up (annual) is recommended.