Left atrial myxofibrosarcoma: Diagnostic approach through imaging techniques

Abstract

Primary cardiac sarcomas are rare. A 63-year-old woman presented with progressive symptoms of fatigue, palpitations, and dyspnea. Transthoracic echocardiography detected a mass in the left atrium, fixed and probably attached to the interatrial septum suggestive of myxoma. Transesophageal echocardiography confirmed the existence of a large lobulated mass in the left atrium measuring 45 mm × 25 mm in diameter. Subsequent cardiac magnetic resonance imaging showed a mass of heterogeneous appearance, with broad base of implantation on the posterior wall of the left atrium. The extension study with multidetector computed tomography showed superficial infiltration of the atrial wall, without involvement of the mitral valve or pulmonary veins and no extension to other extracardiac structures. The patient underwent surgery resecting a bilobed mass, smooth and yellowish, strongly attached to the posterior wall of left atrium. The pathologic study was consistent with the diagnosis of myxofibrosarcoma. <Learning objective: Primary cardiac tumors are among the most challenging disease entities to diagnose because of their rarity and highly variable and usually nonspecific clinical presentation. Although the definitive diagnosis of a cardiac tumor, whether benign or malignant and the tumor type is provided by histological examination, imaging techniques are essential for confirming the existence of a cardiac mass and characterizing the tumor before obtaining a sample for pathologic examination.>.

Keywords: Cardiac tumors; Echocardiography; Magnetic resonance imaging; Myxofibrosarcoma; Myxoma.

Fig. 1

(A) Transthoracic echocardiogram apical four-chamber view showing a large mass that occupies almost the entire left atrium. (B) Transesophageal echocardiogram shows a lobulated mass protruding through the mitral valve. LV, left ventricle; RV, right ventricle; RA, right atrium.

Fig. 2

Cardiac magnetic resonance imaging. (A) STIR sequence axial view showing the mass strongly hyperintense relative to the myocardium. (B) Delayed enhancement contrast sequence shows the heterogeneous appearance of the mass with central areas of necrosis.

Fig. 3

Cardiac multidetector computed tomography. (A) Oblique four-chamber view showing the big mass in the left atrium without affecting the pulmonary venous drainage. (B) Oblique two-chamber view shows the mass infiltrating the posterior wall of the atrium, which receives its vascular supply.

Fig. 4

Surgery pictures. (A) View of the mass after performing the left atriotomy. (B) Bilobed mass of 3 cm × 5 cm in diameter once resected.

Fig. 5

Pathological study. (A) Tumor is composed of myxoid cells adopting a diffuse pattern with some larger cells, alternating with zones of necrosis. (B) At higher magnification these cells are large with dense cytoplasm, abundant and irregular nucleus, chromatin rough and frequent mitotic figures (arrows).