PMC5301097_01
Radiographs of the thigh at the initial presentation. a Anteroposterior view. b Lateral view. Abnormal opacity without calcification can be seen in the posteromedial thigh (white arrowheads).
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F1
On the plain radiographs, there was no calcification or scalloping of the femur (Fig 1).
On MRI, the lesion was depicted as a low-intensity lesion on T1WI (a) and as a high-intensity lesion on T2WI (b) in the semimembranosus muscle. The lesion was enhanced after gadolinium-based contrast administration (c, d).
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F2
T1-weighted image (T1WI) and as iso- to high intensity on the T2-weighted image (T2WI), which was enhanced after gadolinium-based contrast administration (Fig 2). The blood examination results were all in the normal range.
The cut surface of the tumor showed a white to tan red solid mass encapsulated in the muscle (a). Under hematoxylin and eosin staining, the tumor showed expansive growth inside the muscle (b), and was composed of oval to polygonal neoplastic cells with small round-to-oval nuclei admixed with variable amounts of lymphocytes, compatible with type B2 thymoma (c).
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F3
On histopathologic examination, the lesion was composed of oval to polygonal neoplastic cells with small round-to-oval nuclei, admixed with variable amounts of lymphocytes compatible with type B2 thymoma metastasis (Fig 3).