Morphology and clinical presentation
Most myxomas have a lobulated surface and a polypoid shape on a stalk (pedunculated), making them mobile. A villous type (villous type) is less common—a gelatinous tumor with fragile projections. This specific type is most prone to fragmentation, causing peripheral embolism, which requires early surgical intervention.
Clinically, myxoma can mimic infective endocarditis: patients present with an elevated ESR and clubbing. However, in myxoma, blood cultures remain sterile and the spleen is not enlarged (no splenomegaly).
A distinct category is familial myxomas (less than 10% of cases), which occur in young individuals (median age 20 years) and tend to be multiple and recurrent. They may be part of the autosomal dominant Carney complex (Carney complex), associated with endocrine disorders and patchy skin pigmentation.
Diagnostic imaging of myxomas
A combination of imaging modalities is used to detect myxomas:
- Chest radiography (CXR): Often shows no changes, but may reveal isolated left atrial enlargement, signs of pulmonary venous or arterial hypertension, and occasionally tumor calcification.
- Echocardiography (EchoCG): Is the first-line method. The screen demonstrates a hyperechoic mass (hyperechoic mass) with a heterogeneous structure attached to the interatrial septum. The stalk and prolapse of the tumor through the mitral valve orifice are clearly visible.
- Contrast-enhanced CT: Shows a lobulated, low-attenuation mass (due to gelatinous tissue). Contrast enhancement is heterogeneous in the delayed phase (due to necrosis and cysts). Approximately 14% of cases (more frequently on the right side) show foci of calcification. Prolapse through the mitral valve is a key CT feature distinguishing myxoma from thrombus.
MRI appearance of myxoma
Magnetic resonance imaging allows detailed assessment of the neoplasm's structure. Due to its complex composition (myxoid, fibrous, hemorrhagic, and cystic tissues), the signal is typically heterogeneous:
- T1-weighted images: Mostly hypointense (darker than myocardium). Calcifications appear as dark areas.
- T2-weighted images: Hyperintense (bright).
- SSFP (Cine-MRI): The tumor is slightly brighter than the myocardium, but darker than blood. Its mobility and diastolic prolapse are exceptionally well visualized dynamically.
- Contrast enhancement (gadolinium): Minimal enhancement during the first pass. In the delayed phase, focal signal enhancement appears, associated with fibrous changes within the myxoma.
- Hemorrhages within the tumor can produce high signal intensity on T1 and T2.
Differential diagnosis: Myxoma or Thrombus?
The primary goal of imaging is to differentiate myxoma from an intracardiac thrombus. In complex cases, only postoperative histology provides a definitive diagnosis.
| Sign | Myxoma | Thrombus |
|---|---|---|
| Attachment | Typically pedunculated, attached to the interatrial septum | Broad base (sessile), frequently in the atrial appendage |
| Contrast enhancement (MRI/CT) | Variable focal enhancement | Complete absence of contrast enhancement |
| Background | Frequently normal rhythm | Typically on the background of an enlarged chamber and atrial fibrillation |
| Prolapse | Frequently prolapses through the valve | As a rule, does not prolapse |
Briefly: answers to topical questions
What pathologies and neoplasms are included in the Carney complex in addition to cardiac myxoma?
In addition to cardiac myxoma, the Carney complex is associated with cutaneous manifestations, endocrine abnormalities, and specific neoplasms.
These include:
- Spotty skin pigmentation (spotty skin pigmentation).
- Endocrine abnormalities / endocrine hyperfunction.
- Primary pigmented nodular adrenocortical disease (PPNAD) — can be familial and is frequently associated with Carney complex.
- Testicular tumors.
- Melanotic schwannoma — contains melanin and is associated with Carney syndrome.
What hemodynamic complications and symptoms are caused by myxoma prolapse through the mitral orifice?
Myxoma prolapse through the mitral orifice causes blood flow obstruction, leading to impaired intracardiac hemodynamics and a drop in cardiac output.
Main complications and symptoms include:
- Mitral valve obstruction — causes symptoms mimicking mitral stenosis.
- Heart failure — develops due to filling of cardiac chambers by tumor masses.
- Arrhythmias — occur due to the mass affecting cardiac structures.
- Cardiogenic syncope — syncopal episodes due to a sharp decrease in cerebral blood flow.
Additionally, patients may present with the classic triad: signs of obstruction, peripheral emboli, and constitutional symptoms (fever, anemia).
Which primary malignant cardiac tumors must be differentiated from myxoma?
Differential diagnosis of myxoma should be performed with primary malignant cardiac tumors, primarily sarcomas, as well as lymphomas and primary malignant pericardial tumors.
Malignant cardiac tumors described in the literature include:
- Sarcomas (Sarcomas) — account for nearly all primary malignant cardiac neoplasms and are the second most common primary cardiac tumor after myxoma.
- Angiosarcoma (Angiosarcoma) — the most common malignant cardiac tumor; on echocardiography, it may appear as a mass atypical for myxoma.
- Sarcomas with myofibroblastic differentiation — include undifferentiated sarcoma, leiomyosarcoma, fibrosarcoma, liposarcoma, and osteosarcoma.
- Lymphomas — belong to the group of primary malignant cardiac tumors.
- Primary malignant tumors of the pericardium also stand out among primary malignant cardiac tumors.
What else to study on this topic
- Diagnostic features of Carney complex
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