SALL4 and SF-1 are sensitive and specific markers for distinguishing granulosa cell tumors from yolk sac tumors.

Granulosa cell tumors are classified as juvenile and adult types. They may be misinterpreted as a yolk sac tumor when they exhibit a "reticular" growth pattern and contain prominent mitotic activity. In this study, the authors performed immunohistochemical stains for SALL4 and steroidogenic factor-1 (SF-1) on 27 cases of yolk sac tumors and 24 granulosa cell tumors. Nuclear stains for both antibodies were considered as positive and the intensity of staining was graded as negative, weak, moderate, and strong. All the yolk sac tumors were positive for SALL4 (100%) with moderate to strong grade staining and negative for SF-1 (100%). In contrast, all the granulosa cell tumors were positive for SF-1 (85% moderate to strong grade staining and 15% weak staining) and negative for SALL4 (100%). The difference was significant (P < .01, Student's t test). This result indicates that these 2 markers could be used to distinguish these 2 tumors in a difficult situation.