Fig. 2

Exemplary histopathological microphotographs. Navigational MRI (a) showing the target point for stereotactic biopsy in the same patient as in Fig. 1, A and B. Despite preoperative CST and radiological regression, the histopathological analysis was clearly diagnostic for PCNSL showing typical large pleomorphic lymphoblastic tumor cells with patternless growth, partly cuffed around vessels and few apoptotic tumor cells (b). Immunohistochemistry was excessively positive for CD20 (c). Navigational MRI and target point (d) of a patient without preoperative CST. Microphotographs show diffusely patternless growth of lymphoblastic tumor cells in HE staining (e) and distinct positive immunohistochemistry for CD20 (f) in this patient without preoperative CST. All histopathological images were generated with 200-fold magnification. Recognizable color differences are due to different age of histopathological specimens