[793] Sall4 and SF-1 Are Sensitive and Specific Markers for Distinguishing Granulosa Cell Tumors from Yolk Sac Tumors

Shuting Bai, Shi Wei, Amy Ziober, Yuan Yao, Zhanyong Bing. Hospital of the University of Pennsylvania, Philadelphia, PA; University of Alabama at Birmingham, Birmingham, AL

Background: Granulosa cell tumors could be misinterpreted as yolk sac tumors when thry exhibit “reticular” growth patterns and contain prominent mitotic activities. Even though immunostains of alpha-fetoprotein and inhibin can be used to distinguish these two tumors, the reliability of antibodies targeting alpha-fetoprotein in tissues is often questioned. Since the approach to treating these two tumors is very different, alternative markers need to be explored. Sall4 is a relatively specific marker for germ cell tumors including yolk sac tumor. Steroidogenic factor-1 (SF-1) is a nuclear receptor and has been shown to be expressed in various sex cord stromal tumors. Whether Sall4 and SF-1 can be used as markers to distinguish yolk sac tumors from granulosa cell tumors has not been elucidated.
Design: 24 cases of granulose cell tumors and 27 cases of yolk sac tumors, retrieved from the pathology archives of the Hospital of the University of Pennsylvania and University of Alabama at Birmingham Hospital, were immunohistochemically stained with SF-1 and Sall4 antibodies by following manufacturers' instruction. Nuclear stains for both antibodies were considered as positive and the intensity of staining was graded as negative, weak, moderate, and strong. Statistical significance was derived utilizing the student's t test.
Results: There were 24 female patients and 27 male patients. All the cases were reviewed to confirm the diagnoses. 23 out of 24 granulose cell tumors (96%) were from ovaries, one (4%) was from a testis. Most of the yolk sac tumors were from testis (18 cases, 67%), 1 case from ovary (4%) and rest cases are from anterior mediastinal area or other sites with metastatic tumors (8 cases, 29%) of male patients. All yolk sac tumors were positive for Sall4 (100%) with moderate to strong grade staining intensity and negative for SF-1 (100%). In contrast, all granulose cell tumors were positive for SF-1 (85% moderate to strong grade staining intensity and 15% mild grade staining intensity) and negative for Sall4 (100%). The difference was statistically significant (p<0.01).
Conclusions: This study showed that all granulose cell tumors were positive for SF-1 and negative for Sall4. In contrast, yolk sac tumors were positive for Sall4 and negative for SF-1. This result indicated that these two markers could be used to distinguish these two tumors in a difficult situation.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 161, Monday Morning

 

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