Interatrial Septum Myxoma

Author(s)

Henrique Rodrigues; Pedro Belo Oliveira; Paulo Donato; Cristina Marques

Patient

male, 55 year(s)

Clinical Summary

The authors describe a case of a 55 years male, with class II cardiac insufficiency, with a mass in left atrium detected by echocardiography. MR showed a mass with 4cm arising from the interatrial septum, with similar intensity to myocardium on T1, high intensity T2, and intense enhancement after gadolinium.

Clinical History and Imaging Procedures

Fifty-five years old male went to his physician with cardiac insufficiency complains, with recent outset. Laboratory data and ECG showed no significant changes. Echocardiography described a heterogeneous mass, dependent of interatrial septum. Cardiac MR was performed thereafter: T1-weighted SE images showed homogeneous moderate signal intensity mass, with 4cm, arising from interatrial septum (Fig 1). T2- weighted SE images showed an increase of signal in the mass (Fig 2). After gadolinium there was intense enhancement (Fig 3).

Discussion

Primary cardiac tumours of the heart are rare, approximately three-quarters are benign. Myxomas are the most common type in all age groups, there is a female predilection and occur commonly in the third to sixth decades [1]. The most common clinical manifestation mimics mitral disease, presenting as chest pain, arrhythmias, sudden death and peripheral emboli. May also presents with constitutional signs, Raynaud`s phenomenon, hypergammaglobulinemia, anemia, polycythemia, leukocytosis, thrombocytopenia or thrombocytosis [1]. Myxomas are usually pediculated, preferentially located in the septum of left atrium, heterogeneous, have low signal intensity on T1-weighted images, high signal intensity on T2-weighted sequences and show low to high enhancement after gadolinium [2]. Several other lesions can present as left atrium tumour mass: Lipomatous hypertrophy of septum, true cardiac lipomas, liposarcoma, parietal thrombi and metastatic tumours. In lipomatous hypertrophy of septum there is diffuse involvement of the interatrial septum, spanning the fossa ovalis, showing on T1-weighted SE images a high signal intensity mass within the septum, with the same signal intensity as subcutaneous fat, as well as in the other sequences such as T2-weighted SE and gradient echo techniques. If doubt persists, fat-suppression techniques may help in demonstrating reduction of signal in the mass as in subcutaneous fat [3]. True cardiac lipomas differ by the presence of a capsule; they can be subendocardic, subepicardic or located within the myocardium but have the same MR characteristics of lipomatous hypertrophy [4]. Liposarcoma is a rare cardiac tumour, right chambers are more commonly affected, and tumours are mainly infiltrative and can invade pericardium. Thrombus usually don’t have a pedicle and may show different characteristics depending upon its age: Fresh thrombus may have variable signal intensity on T1 and high signal on T2 images; chronic thrombus have low signal intensity on both T1 and T2; after gadolinium, low contrast enhancement is usually depicted, except for hyperacute thrombus [5]. Metastatic tumours are 20 to 40 times more frequent than primary tumours. The diagnosis is easy when the primary tumour is known; these lesions usually have intermediate signal on T1-weighted images, high signal on T2-weighted images, and enhance with gadolinium.

Final Diagnosis

Interatrial septum myxoma

MeSH

Heart [A07.541]
The hollow, muscular organ that maintains the circulation of the blood.
Heart Septum [A07.541.459]
The thin membranous structure between the two heart atria or the thick muscular structure between the two heart ventricles.
Heart Neoplasms [C14.280.459]
Myxoma [C04.557.450.565.550]
A benign neoplasm derived from connective tissue, consisting chiefly of polyhedral and stellate cells that are loosely embedded in a soft mucoid matrix, thereby resembling primitive mesenchymal tissue. It occurs frequently intramuscularly where it may be mistaken for a sarcoma. It appears also in the jaws and the skin. (From Stedman, 25th ed)

References

Colucci W, Price D. Cardiac Tumors, Cardiac Manifestations of Systemic Diseases, and Traumatic Cardiac Injury. Braunwald, E; Harrison´s Principles of Internal Medicine, New York, 2001, pp. 1372-1377

Sommer T, Vahihaus C, Hofer U, Smekal A von, Wardelmann E, Bierhoff E, Pauleit D, Wilhelm K, Textor J, Schild H. MRI diagnosis of cardiac Myxomas: sequence evaluation and differential diagnosis. Rofo Fortschr Geb Rontgenstr Neuen Bildgeb Verfahr 1999;170:156-162

Didier D, Ratib O. Dynamic cardiovascular MRI- Principles and practical examples. Stuttgart-New York: Thieme, 2003; 99-111

Oyama N, Oyama N, Komatsu H, Okita K, Yonezawa K, Fujii S, Miyasaka K, Kitabatake A. Left ventricular Asynchrony caused by an Intramuscular Lipoma. Circulation 2003; 107: 200-201

Paydarfar D, Krieger D, Dib N, Blair RH, Pastore JO, Stetz JJ Jr, Symes JF. In vivi magnetic resonance imaging and surgical histipathology of intracardiac masses: distinct features of Subacute thrombi. Cardiology 2001; 95: 40-47

Citation

Henrique Rodrigues; Pedro Belo Oliveira; Paulo Donato; Cristina Marques (2005, Jun 20).

Interatrial Septum Myxoma, {Online}.

URL:

DOI: 10.1594/EURORAD/CASE.3838

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Published 20.06.2005
DOI 10.1594/EURORAD/CASE.3838
SectionCardiac Imaging
Case-TypeClinical Case
Views 53
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Figure 1

MR T1

T1-weighted SE image shows a mass with 4 cm, located in the interatrial septum, with the same intensity as cardiac muscle.

Figure 2

MR T2

T2-weighted SE image depicts a homogeneous increase of signal in the mass areas.

Figure 3

MR T1 after Gd

T1-weighted after gadolinium, showing homogeneous enhancement in the mass.

Figure 1