Fig. 2

The radiological, pathologic diagnosis and treatment of case 2. Brain contrast-enhanced MRI (a-d): A ring enhancement space-occupying lesion 4.7 × 4.6 × 3.4 cm in the right cerebellar hemisphere with an amygdala cerebelli herniation before treatment (In May, 2021) (a). Having a PR after 2 months treatment (In August, 2021) (b). Presenting a progressive disease after 6 months treatment (In December, 2021) (c). Achieving a CR after 13 months treatment (In August, 2022) and keeping a CR after 19 months treatment (In February, 2023) (d). Histological characteristics (e-h): Diffuse distribution of tumor cells with flaky coagulation necrosis was found. The volume of most cells is large. The nucleus is slightly irregular, and nucleolus enlargement and nuclear division were found (H&E staining, original magnification×200) (e). The diffuse expression of CD20-positive tumor cells (immunohistochemical staining, original magnification×200) (f). The tumor cells with positive expression of Pax-5 (immunohistochemical staining, original magnification×200) (g). The positive EBV-encoded small RNA (EBER) was found (situ hybridization, original magnification×200) (h). Treatment regimen adjustment (i)