PMC5457922_01
Mediastinal magnetic resonance imaging shows high signal intensity on T2-weighted imaging (arrow), and also on fat-suppressed T2-weighted imaging (arrow).
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MRI of the mediastinum revealed a low-intensity signal in the sternum on T1-weighted imaging (T1WI) and a high-intensity signal on T2-weighted imaging (T2WI) and fat-suppressed T2WI (Fig. 1).
Gallium-67 scintigraphy images in the anterior view (48 hours): showing abnormal uptake in the sternum (arrow).
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Gallium scintigraphy revealed abnormal uptake in the sternum (Fig. 2).
Pathological findings of the aorta. (A): Macroscopically, the aorta shows no tumorous lesion. (B): The aorta shows tumorous lesion in the intima [arrow; Hematoxylin and Eosin (H&E) staining, bar: 1 mm]. (C): Spindle tumor cells proliferate at the intimal surface (H&E staining, bar: 40 mum). (D) Tumor cells stain positive for vimentin (vimentin stain, bar: 40 mum).
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Immunohistochemical staining of tumor cells were positive for vimentin (Fig. 3), which suggests that the tumor cells were derived from mesenchymal cells.
Pathological findings of the superior mesenteric artery. (A): The superior mesenteric artery is obstructed by a fibrin thrombus [arrow, Hematoxylin and Eosin (H&E) staining, bar: 5 mm]. (B): The superior mesenteric artery is obstructed by a fibrin thrombus including tumor invasion (H&E staining, bar: 20 mum).
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S-100 protein, CD56, and desmin were negative; alphaSMA (smooth muscle actin) and HHF-35 (muscle-specific actin) were almost negative; and Ki-67 was positive for 16% cells. Spindle tumor cells were observed in the superior mesenteric artery (Fig. 4).
Pathological findings of the metastatic lesion. (A) Micrograph confirming metastasis in the sternum [Hematoxylin and Eosin (H&E) staining, bar: 50 mum]. (B) Micrograph confirming metastasis in the peritracheal lymph node (H&E staining, bar: 50 mum).
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Proliferation of spindle tumor cells was observed in the ribs, thoracic vertebrae, sternal medullary cavity near the sternoclavicular joint, and peritracheal lymph nodes (Fig. 5).