Fig. 3.

A, Hematoxylin and eosin features of the tumor (original magnification 40 ×): sheets of poorly differentiated, monotonous, ovoid cells, with a high nuclear to cytoplasmic ratio. Homer-Wright rosettes were common. B, Tumor cells with necrotic areas and foci of calcifications .C, Immunoperoxidase for CD99 (40×) showed predominantly membranous staining of tumor cells composed of small round cells with round nuclei and scant cytoplasm arranged in cohesive lobules. D, Immunoperoxidase for ACTH (10×) showed Diffuse cytoplasmic staining of tumor cells.