Histopathological examination of the recurrent tumor. (a) Magnification, ×200. (b) Magnification, ×400. H&E staining showed that the tumor cells exhibited increased atypia and pleomorphism compared with those in the primary tumor, varying from small and bland to enlarged, bizarre, pleomorphic and multinucleated. Abundant myxoid matrix and elongated curvilinear capillaries were also observed.