Undifferentiated Cardiac Sarcoma of the Mitral Valve: Multimodal Imaging Assessment

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A 75-year-old female patient was referred for transesophageal echocardiography prior to pulmonary vein isolation for planned treatment of symptomatic paroxysmal atrial fibrillation, resulting in the incidental detection of an expansive intracardiac mass around the mitral valve. The mass involved both leaflets and both papillary muscles, leading to functional impairment of the mitral valve with moderate mitral regurgitation and a mild stenotic effect (Figure, A; Movie 1).

Images in a 70-year-old female patient with high-grade undifferentiated pleomorphic sarcoma of the mitral valve. (A) Transesophageal echocardiographic images show intracardiac mass around the mitral valve apparatus (arrows). (B) Multiplanar cardiac CT reconstructions (short-axis [1] and four-chamber [2] planes) of the mass show marked thickening (arrows) of both myocardial leaflets without evidence of infiltration into the adjacent ventricular myocardium. (C) Cardiac MRI performed at 1.5 T, short-axis plane: Precontrast T1-weighted turbo spin-echo image (1) shows iso- to hyperintense signal of the mitral valve mass (arrow) compared with that of the myocardium; early gadolinium enhancement image (2) acquired 2 minutes after contrast material injection with a long inversion time of 550 msec shows very hypointense lesions (arrow) surrounding the mitral mass, suggestive of either appositional thrombi or necrosis foci; T2-weighted image (3) shows hyperintense signal (arrow) surrounding the mass. (D) Histopathologic image shows irregularly arranged, atypical cells with bizarre nuclei (hematoxylin-eosin stain; magnification, ×100). (E) Macroscopic image of the resected cardiac mass shows diffuse areas of fibrosis associated with hemorrhage, most likely a bystander response of the peritumoral tissue.

Movie 1:

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Transoesophageal Echocardiography: Cine imaging demonstrated incidental detection of an expansive intracardiac mass around the mitral valve. The mass involved both markedly thickened leaflets and both papillary muscles, with pedunculated mobile structures prolapsing into the left atrium during systole, leading to functional impairment of the valve (moderate mitral regurgitation and mild stenosis).

CT images did not show any calcification, and the findings confirmed that the mass involved only the mitral valve and papillary muscles (Figure, B). Cardiac MRI showed the following atypical features for a malignant lesion: no evidence of infiltrative growth into the adjacent ventricular myocardium, only minimal first-pass perfusion, signs of several appositional thrombi, and only minimal late gadolinium enhancement (Figure, C; Movie 2). An interventional biopsy of the lesion revealed histologic and immunohistochemical findings compatible with a high-grade undifferentiated pleomorphic sarcoma (Figure, D).

Movie 2:

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Cardiac MRI Cine Imaging: Cardiac MRI cine imaging confirmed the presence of an expansive intracardiac mass in the region of the mitral valve, involving both the leaflets and the papillary muscles without evidence of infiltrative growth into the adjacent ventricular myocardium. Cardiac MRI Tissue Characterization: Atypical features for a malignant lesion without evidence of infiltrative growth in the adjacent myocardium, only minimal first-pass perfusion, signs of several appositional thrombi on early gadolinium enhancement images and only minimal late gadolinium enhancement (images not shown).

The patient underwent surgery 6 weeks after biopsy. Due to an infiltrating growth into the papillary muscles, left atrium, and left ventricle (Figure, E; Movie 3), the sarcoma could not be removed completely. Intraoperatively, the free wall of the left ventricle ruptured with subsequent hemorrhagic shock. The patient died on the 3rd postoperative day.

Movie 3:

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In the operating theater (5 months after the initial cardiac MRI scan), the sarcoma was infiltrating the papillary muscles of the mitral valve, as well as the left atrium and ventricle.

Keywords: CT, Echocardiography, MRI, Biopsy/Needle Aspiration, Cardiac, Heart, Mitral Valve, Neoplasms