PMC9856333_01
Preoperative transthoracic and transoesophageal echocardiogram. (A) Transthoracic echocardiogram, apical four-chamber view. Transthoracic echocardiogram showed a functional mitral stenosis due to large masses in the left atrium with a mean gradient of 13 mmHg; masses protruding into the left ventricle creating an outflow gradient of 130 mmHg across the aortic valve; a tricuspid regurgitation gradient of 50 mmHg; and no pericardial effusion. (B and C) Transoesophageal echocardiogram, four-chamber view, 0  rotation (B) and two-chamber view, 42  rotation (C). Transoesophageal echocardiogram showed massive masses in the left atrium and ventricle, seemingly perforating the mitral valve and extending into the left ventricular outflow tract, resulting in functional left ventricular outflow tract obstruction and functional mitral stenosis. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.
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The electrocardiogram (see Supplementary material online, Figure S1) showed normal sinus rhythm, left axis deviation, and poor R-wave progression. A TTE (Figure 1A) showed a functional mitral stenosis due to large masses in the left atrium with a mean gradient of 13 mmHg; masses protruding into the left ventricle creating an outflow gradient of 130 mmHg across the aortic valve; a tricuspid regurgitation gradient of 50 mmHg; and no pericardial effusion. A transoesophageal echocardiogram (TOE; Figure 1BandCandSupplementary material online, Video S1) showed massive masses in the left atrium and ventricle, seemingly perforating the mitral valve and extending into the left ventricular outflow tract (LVOT), resulting in functional LVOT obstruction and functional mitral stenosis.
Positron emission tomography/computed tomography. (A) The Positron emission tomography/computed tomography scan revealed masses suspicious for malignancy (due to strong tissue metabolic activity) in the left atrium, left ventricle, and septum. All lymph nodes in the mediastinum were without strong metabolic activity and thought to be benign. The PET tracer used was 18F-fluorodeoxyglucose. Panels A-C show axial view images, and Panel D shows the frontal view. Computed tomography is contrast-enhanced in the venous phase. L, left; R, right.
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Chest X-ray (see Supplementary material online, Figure S2) showed pulmonary congestion, Kerley B lines, and bilateral pleural effusion. As the nature of the detected mass was still unclear, a PET/CT scan (Figure 2) was performed, revealing masses suspicious for malignancy (due to strong tissue metabolic activity) in the left atrium, left ventricle, and septum.
Gross pathology and histopathology. (A) Gross specimen after tumour resection. The resected tumour measured 85 x 80 x 30 mm. (B-E) Histopathology, haematoxylin, and eosin stain. The pathological assessment revealed an intimal sarcoma with non-radically resected tumour borders. (B) Myocardium (left) and infiltrating tumour cells, lymphocytes, and macrophages (right). Degenerated myocytes are seen in the transition zone. (C) Myocardium (right) and tendinous cord (middle). The tumour (left) fills out the whole ventricular cavity and has grown into the endocardium which has thickened as a reaction to the tumour. (D) Myocardium (upper left), tendinous cord (middle), and tumour. The myocytes have reversible changes (including fluid accumulation and degeneration of myofibrils), most likely as a reaction to the tumour. (E) Close-up of tumour with blood vessels.
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Apart from non-radical tumour resection (Figure 3A), the surgery included patch implantation in the left atrium and left ventricle (Supple Peri-Guard, model number 60PC-0404SN), bioprosthetic mitral valve replacement (Epic Mitral 31 mm FlexFit valve, model number E100-31M), and a Freestyle 27 bioprosthesis (model number FR995-27) for the aortic root. Postoperative TTE (9 days after the surgery; see Supplementary material online, Figure S3) showed well-functioning bioprostheses, no visible residual tumour masses, and a normal left ventricular ejection fraction. The pathology assessment revealed an intimal sarcoma with non-radically resected tumour borders (Figure 3B-E).