PMC6580310_01
A computed tomographic scan of the chest shows an anterior mediastinal mass.
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An asymptomatic 55-year-old woman underwent a chest roentgenogram during a routine checkup; it showed an abnormal shadow in the mediastinal left upper lung field (Fig. 1).
A computed tomographic scan of the chest shows an anterior mediastinal mass.
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Chest computed tomography images showed a well-defined anterior mediastinal mass measuring 4.8 x 4.0 cm (Fig. 2).
Magnetic resonance imaging of the chest shows high intensity on T2-weighted images with suspected invasion to the upper lobe of the left lung.
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Chest magnetic resonance imaging showed an iso-intensity mass on T1-weighted images and high-intensity mass on T2-weighted images, with suspected invasion to the upper lobe of the left lung (Fig. 3).
Positron emission tomography with 18F-fluorodeoxyglucose shows high 18F-fluorodeoxyglucose accumulation at the lesion.
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Positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) showed high FDG accumulation at the lesion [maximum standardized uptake value (SUVmax) of 12.75] (Fig. 4).
(A) The tumor cells with hyperchromatic nuclei proliferatein layered nest pattern with peripheral palisading and necrosis. Tumor embolism of the left innominate vein (B) or venous permeation in the tumor (C) are found. (D) Tumor cells are immunohistochemically positive for synaptophysin.
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Histopathological examination of the tumor specimen revealed tumor cells with hyperchromatic nuclei proliferating in a layered nest pattern with peripheral palisading and necrosis (Fig. 5A). Tumor emboli (Fig. 5B) or venous permeation (Fig. 5C) were frequently seen. Immunohistochemically, the tumor cells were positive for synaptophysin (Fig. 5D) and chromogranin A, but negative for cytokeratin 5/6.