Representative photomicrographs of the tumor specimens. Higher cell densities (A, B; 100×, 200×, respectively, H & E) with perinuclear haloes (C; 200×, H & E; arrows), and microscopically round-to-oblong cells with hyperchromatism and pleomorphism (D; 400×, H & E), are compatible with AO. (E, F) Clusters of capillary or plexiform capillaries (arrows), and the irregular mitosis densities were higher (100×, 200×, respectively, H & E). (G, H) Obvious false fence structure (thick arrows)-shaped necrosis (slim arrows; 100×, 200×, respectively, H & E). (I, J) After the right iliac bone marrow needle biopsy, cells in the bone marrow specimen from the patient were small and round with a thin rim of eosinophilic cytoplasm (400×, H & E).