PMC6357286_01
Axial view of pre-contrast (a) and contrast-enhanced (b) CT demonstrated a multi-nodular tumor with heterogeneous enhancement in the anterior mediastinum.
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Contrast-enhanced CT demonstrated a multi-nodular and heterogeneous mass 5.4 cm in max. dia. located mainly in the anterior mediastinum (Fig. 1).
MRI revealed a mass with iso-signal intensity relative to muscles on a T1-weighted image (a) and low signal intensity on a T2-weighted image (b). This lesion showed hyperintensity on DWI with a b-value of 1000s/mm2 (c), and the ADC values ranged from 0.7 to 0.9 x 10-3 mm2/s (d). The dynamic contrast-enhancement study revealed a rapid-plateau pattern (e,f).
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The mass showed isointensity relative to muscles on T1-weighted images (Fig. 2a) and hypointensity on T2-weighted images (Fig. 2b). This lesion showed hyperintensity on the DWI (Fig. 2c), and the ADC values ranged from 0.7 to 0.9 x 0.10-3 mm2/s (Fig. 2d). We then plotted the average signal intensity within the ROI against time, and a time-intensity curve (TIC) was constructed which revealed a rapid-plateau pattern (Fig. 2e,f).
18F-FDG-PET/CT showed a high accumulation of FDG with a maximum standardized uptake value of 9.88 (a). No other abnormal uptake was observed (b).
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An 18-fluorodeoxyglucose (FDG)-PET examination revealed abnormal uptake in this tumor with a maximal standardized uptake (SUVmax) value of 9.66 (Fig. 3).
Macroscopically, the tumor was circumscribed and solid. Partial infiltration toward the right upper lobe was observed (a,b). Microscopically, polygonal, spindle, or epithelioid-shaped cells with bizarre nuclei proliferated in a sheet, storiform, or fascicular pattern. Fibrous, hyalinized and myxomatous stroma was also seen. Both epithelioid (c) and sarcomatous (d) components were observed. These findings indicated a malignant mesothelioma with a biphasic pattern.
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Histopathologically, both epithelioid and sarcomatous components were identified (Fig. 4).