Microscopic examination of a tumor shows Call-Exner bodies. They are seen in:
Granulosa cell tumor
Yolk Sac tumor
Choriocarcinoma
Dysgerminoma
Microscopic examination of granulosa cell tumor shows predominantly granulosa cells with pale, grooved, "coffee bean" nuclei. The characteristic microscopic feature is the Call-Exner body -- a rosette arrangement of cells around an eosinophilic fluid space. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 36. Ovarian Germ Cell and Sex Cord-Stromal Tumors. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.