[1126] Evaluation of Wilm's Tumor-1 (WT-1) Immunohistochemistry in Synchronous Primary Adenocarcinomas of the Endometrium and Ovary

Taylor M Deal, John R Ross, Michael G Conner. University of Alabama at Birmingham, Birmingham, AL

Background: Primary ovarian papillary serous (OPS) carcinomas often demonstrate metastases to the uterus. Occasionally, specimens show tumor within the ovary as well as endometrium without evidence of metastases to the uterine serosa. Many consider these to be synchronous primary papillary serous (SPPS) carcinomas that developed independently. WT-1 immunohistochemistry has been shown to be positive in > 90% of primary OPS carcinomas but in less than 20% of cases of isolated primary endometrial papillary serous (EPS) carcinoma; endometrioid pattern carcinomas are consistently negative. These different immunoprofiles suggest separate biological mechanisms of development for OPS and EPS. To our knowledge, no study has evaluated a series of SPPS to determine if the ovarian and endometrial components demonstrate a similar or dissimilar WT-1 immunohistochemical profile.
Design: The following cases were collected from UAB archives: SPPS (N=7), synchronous primary endometrioid adencocarcinoma (N=11), and isolated EPS adenocarcinoma (N=12). WT-1 IHC was performed on representative tumor sites and the slides were evaluated on an intensity scale based on percentage of darkly staining tumor cells: 0, 1+ (<20%), 2+ (20-50%), 3+ (50-80%), 4+ (80-100%). Cases showing 2+ and greater staining were considered significantly positive.
Results: 57% of the SPPS cases (4/7) showed strong staining (3+ and 4+) in both the ovarian and endometrial tumor. Positive cases showed similar staining profiles while negative cases showed absence of expression in both tumors. WT-1 was positive in 17% (10/12) of the isolated EPS cases. All 11 synchronous endometrioid cases were negative for WT-1.
Conclusions: Our results for isolated EPS and synchronous endometrioid carcinomas are in concurrence with previous studies. A greater percentage of SPPS cases showing WT-1 expression and absence of heterogeneity between both carcinoma components suggest two possibilities: 1) metastasis of tumor between ovary and endometrium instead of two independent tumors and 2) SPPS tumors have a different biological mechanism of development due to negative WT-1 in the majority of isolated EPS while WT-1 showed expression within the endometrial tumor in a majority of SPPS cases. Additionally, both mechanisms may play a role. Distinguishing these possibilities is important for determining prognosis and appropriate therapy in these patients. Future studies involving a greater number of these cases as well as molecular evaluation are required to further evaluate these unusual tumors.
Category: Gynecologic & Obstetrics

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 173, Monday Morning


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