Mesentery solitary fibrous tumor with postoperative recurrence and sarcomatosis: A case report and review of literature

Figure 4 Microscopic features. The heterogeneous cell population comprised of mostly spindle cells with fibrous collagen proliferation as well as various other cell populations exhibiting patternless or storiform growth. No tumor necrosis, nuclear polymorphism, or cellular atypia was noted. The nuclear mitotic index was 4 mitoses/50 high-power fields (A: × 100 original magnification; B: × 400 original magnification).