Atrial Myxoma Workup

Updated: Jun 20, 2019
  • Author: Gyanendra K Sharma, MD, FACC, FASE; Chief Editor: Richard A Lange, MD, MBA  more...
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Workup

Laboratory Studies

Laboratory studies are nonspecific and nondiagnostic for atrial myoma. If present, abnormalities may include the following:

  • Elevated erythrocyte sedimentation rate (ESR) and elevated C-reactive protein and serum gamma globulin levels

  • Leukocytosis

  • Anemia may be normochromic or hypochromic. Hemolytic anemia may occur because of the mechanical destruction of erythrocytes by the tumor.

  • Serum interleukin-6 levels may be raised and can be used as a marker of recurrence.

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Echocardiography

Although transesophageal echocardiography is more sensitive, two-dimensional (2-D) echocardiography is usually adequate for the diagnosis.

Tumor location, size, attachment, and mobility can be assessed with this technique. Because tumors may be in multiple locations, all four chambers should be visualized.

An atrial myxoma must be differentiated from a left atrial thrombus. The thrombus is usually situated in the posterior portion of the atrium and has a layered appearance. Presence of a stalk and mobility favors atrial myxoma.

Doppler echocardiography can show the hemodynamic consequences of atrial myxoma. The findings are consistent with mitral stenosis or regurgitation.

Transesophageal echocardiography (TEE)

TEE has better specificity and 100% sensitivity compared to transthoracic echocardiography (TTE). There is good resolution of both the atria and the atrial septum, and there is better visualization of anatomic details of the tumor and stalk.

This imaging modality reveals smaller (1-3 mm in diameter) vegetations or tumors, visualizes atrial appendages, and detects shunting.

TEE is advisable for myxoma syndrome, as there may be multiple less-common sites (See the image below.)

Atrial myxoma. This is a transesophageal echocardi Atrial myxoma. This is a transesophageal echocardiogram.
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Other Imaging Studies

Radiography

Chest radiographic findings include an abnormal cardiac silhouette, mimicking mitral stenosis; an unusual intracardiac tumor calcification; and pulmonary edema.

Magnetic resonance imaging (MRI)

MRI provides useful information about size, shape, and surface characteristics on T1-weighted images. Cine MR gradient echo (GRE) images can demonstrate the mobility of a tumor. Point of attachment is best visualized by MRI with a postsurgical correlation of 83%. In a small series, MRI was superior to CT scan, which showed only 30% correlation for the site of attachment.

Information about tissue characteristics can be used to differentiate a tumor from a thrombus.

Computed tomography (CT) scanning

Cardiac CT scanning can be used not only to evaluate the coronary arteries and cardiac structures, but this modality can also be used to differentiate the characteristics of the myxoma from intracardiac thrombus and other cardiac pathologies. [31] Myxomas are larger than a thrombus and have typical site of origin, shape, mobility, and occurrence of prolapse. [32]

Degree of attenuation or presence of calcification is not useful to differentiate atrial myxoma from a thrombus.

Nuclear imaging

Fluorodeoxyglucose positron emission tomography (FDG-PET) scanning is not typically indicated in the evaluation for myxoma. Myocardial involvement is rare and only few cases have been reported showing hypermetabolic hypodense areas. [33]

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Other Tests

If petechiae are present, a skin biopsy may reveal the presence of elongated or spindle-shaped, myxomatous, endothelial-like cells with round or oval nuclei and prominent nucleoli.

Electrocardiography may show left atrial enlargement, atrial fibrillation, atrial flutter, or conduction disturbances.

In suspected cases of Carney complex, molecular genetic testing for PRKAR1A should be performed to confirm the diagnosis. The family members of the PRKAR1A -positive patients should undergo genetic screening and evaluation for cardiac and extracardiac manifestations of the disease. [34]

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Procedures

Cardiac catheterization

Preoperative cardiac catheterization and angiography may be of value to evaluate for neovascularization. [5]

Cardiac catheterization is usually performed to exclude coexistent coronary artery disease in patients older than 40 years.

Atrial myxoma appears as an intracardiac filling defect on angiography. This was the pre-echocardiography method of diagnosis. With current imaging modalities, there is no need for angiography.

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Histologic Findings

Histologic studies are characterized by the presence of lipidic cells embedded in a vascular myxoid stroma. [12] Other findings include the following:

  • The cells are polygonal to stellate in shape with scant eosinophilic cytoplasm.

  • Tumor necrosis is present in approximately 8% of patients; calcification is present in 10%-20%.

  • A variable degree of hemorrhage may be present, and mitoses are typically absent.

  • In a series of 37 cases, 74% of tumors showed immunohistochemical expression of interleukin-6 whereas 17% had abnormal DNA content. [35]

  • Complete calcification of the tumor may occur in rare cases. [36]

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