Fig. 2.

Positron emission tomography image of the patient and microscopic and immunohistochemical findings of the primary and recurrent tumors. (A) Positron emission tomography scan shows metastasis to the muscle, lung, mediastinal lymph node (white arrows), liver (black arrow), buttocks, and bones. (B, C) Initial (in 2007) and recurrent tumors (in 2013) show sheets of monotonous cells with oval nuclei with salt-and-pepper chromatin pattern. The recurrent tumor in 2013 shows microvascular proliferation. (D) Glial fibrillary acidic protein is robustly positive in tumor cells. (E) Epithelial membrane antigen shows dot-like positivity, suggesting ependymal tumor. (F) L1CAM shows diffuse strong positivity in the tumor cells, suggesting RELA fusion-positive ependymoma. (G) Ki-67 labeling index in the recurrent tumor was high (37.3%).