Fig. 3
a Histological examination revealed a high grade sarcoma with a fusicellular proliferation organized in a partial storiform pattern, with irregular fascicles, high cellularity, and pleomorphic and bizarre tumor cells with marked atypia and a high mitotic index (hematoxylin and eosin ×20). b Staining was 25 % positive for Ki-67 in the tumor (Ki-67 ×20). c The resected sample was negative for muscle markers (smooth muscle actin ×20) and melanocytic markers CD45 and S10. d The immunohistochemical examinations were positive for CD68, vimentin, and alpha-1-antitrypsin (CD68 ×20)