Fig. 4From: Chordoma dedifferentiation after proton beam therapy: a case report and review of the literaturea Unlike tissue from the first biopsy, the recurrent tumor had prominent areas of necrosis (arrows; 5× magnification). b Mitotic figure (circled) and nuclear pleomorphism were seen at 40× magnification. Spindle cells were seen, but physaliphorous cells were not notedBack to article page