Pathological features of CD10⁻MUM1⁺ follicular lymphoma. In H&E sections, the lymphoma cells form definite follicular structures (A). The follicular structures are confirmed by follicular dendritic cell (FDC) meshwork stained for CD21 (B). In this case, almost all lymphoma cells are large cells and their proliferation shows a “sheet-like” pattern (E). This patient was diagnosed as grade 3B. Lymphoma cells are positive for CD20 (C) and MUM1 (D,F). All figures are from patient 7. Original magnification: (A-D) × 10, (E-F) × 100. Images were visualized using an Olympus AX80 microscope (Olympus, Tokyo, Japan), equipped with (A-D) an Olympus Planapo 4×/0.16 numerical aperture (NA) objective or (E-F) an Olympus Planapo 40×/0.95 NA objective. Images were captured using an Olympus DP70 camera and Olympus DP controller software, and were processed using Olympus DP manager software.