FIG. 2.

Immunohistochemistry for P450 aromatase in poorly differentiated Sertoli-Leydig cell tumors and a Sertoli cell tumor of the ovary. In poorly differentiated Sertoli-Leydig cell tumors, cytokeratin-negative undifferentiated cells with plump cytoplasm were immunoreactive for P450 aromatase, whereas cytokeratin-positive plump cells, suggestive of poorly differentiated Sertoli cells, were not immunoreactive for aromatase. In a Sertoli cell tumor, tall columnar Sertoli cells expressed P450 aromatase. Upper, hematoxylin and eosin (H.E.); middle, cytokeratin (CAM5.2) immunostain; lower, P450 aromatase immunostain. Original magnification, 40×.