PMC6379877_01
(a) Stomach ulcer with epithelioid GIST (50x, hematoxylin and eosin stain). (b) Gastric epithelioid GIST (100x, hematoxylin and eosin stain). (c) Membrane pattern of KIT immunostaining in epithelioid GIST (100x, CD117).
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fig1
The histological diagnosis was ulcerating epitheloid GIST (Figure 1).
(a) Abdominal CT scan with IV contrast showing multiple liver metastases. (b) Chest CT scan showing a filling defect within the contrast-enhanced right atrium which was initially thought to be a large thrombus.
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fig2
The abdominal and chest CT scan (Figure 2) confirmed diffuse liver metastases and revealed an encircling wall architecture of the GIST around the hepatic hilum with a partial obstruction of the common bile duct and a shifting of the portal vein without signs of portal vein thrombosis.
Large atrial mass in (a) the TEE 3D 4-chamber view, (b) the TEE 2D bicaval view, and (c) the TEE 2D short-axis view, conclusive for a mobile large atrial mass.
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fig3
The transthoracic (TTE) and subsequent transoesophageal echocardiography (TEE) disclosed the presence of a 5.3 x 3.4 cm large mass in the right atrium with diastolic prolapsing through the tricuspid valve, without any clear attachment to the atrial wall, with an inhomogeneous appearance, and without vacuolisation (Figure 3), along with a similar 1.1 cm large mass in the IVC (Figure 4) with a suspected but no clear continuation between these two masses even after free style image acquisition.
TEE reveals a similar mass in the IVC.
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fig4
The transthoracic (TTE) and subsequent transoesophageal echocardiography (TEE) disclosed the presence of a 5.3 x 3.4 cm large mass in the right atrium with diastolic prolapsing through the tricuspid valve, without any clear attachment to the atrial wall, with an inhomogeneous appearance, and without vacuolisation (Figure 3), along with a similar 1.1 cm large mass in the IVC (Figure 4) with a suspected but no clear continuation between these two masses even after free style image acquisition.
Cardiac MRI confirms the mass in (a) the right atrium with prolapsing through the tricuspid valve and (b) the contiguous extension of the liver metastasis to the IVC and right atrium (white arrows).
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fig5
Prior to surgery, cardiac magnetic resonance imaging (Figure 5) verified the cardiac findings of echocardiography but also clearly exhibited a propagation of a liver metastasis as a continuous mass to the IVC and right atrium with no adherence to the cardiac wall.
Goldner's trichrome histological staining method at 20x magnification (a) and 80x magnification (b) exhibiting the tumor in the upper layer, fibrosis in the middle green layer, and thrombosis in the lower red layer. Between the fibrotic band and the thrombosis, there are identifiable gut endothelial cells from the VCI.
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fig6
The 50 x 60 mm resected tumor with endothelial infiltration of the IVC, concomitant local thrombosis (Figure 6), and no endocardial and myocardial infiltration of the right atrium was histologically and immunohistologically identical to the prediagnosed GIST (Figure 7) and was a contiguous extension of a liver metastasis to the heart.
(a) Metastasis of epithelioid GIST in the right atrium of the heart (50x, hematoxylin and eosin stain). (b) Strong cytoplasmic pattern of KIT immunostaining in epithelioid GIST in the right atrium of the heart (200x, CD117 antibody).
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fig7
The 50 x 60 mm resected tumor with endothelial infiltration of the IVC, concomitant local thrombosis (Figure 6), and no endocardial and myocardial infiltration of the right atrium was histologically and immunohistologically identical to the prediagnosed GIST (Figure 7) and was a contiguous extension of a liver metastasis to the heart.
Tumor recurrence one week after surgical removal.
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fig8
However, a week after surgery, transthoracic echocardiography (Figure 8) revealed a new mass in the right atrium indicative of early recurrence.