[1127] Differential Vimentin Expression in Ovarian and Endometrial Endometrioid Adenocarcinomas: Diagnostic Utility in Distinguishing Double Primaries from Metastatic Tumors

Mohamed M Desouki, Sarah J Kallas, Omar Hameed, Dineo Khabele, Marta A Crispens, Oluwole Fadare. Vanderbilt University, Nashville, TN

Background: When an endometrioid adenocarcinoma involves both the endometrium and the ovary, the challenge of diagnosing synchronous lesions, and distinguishing such tumors as metastasis from one organ to the other, is well known. While vimentin is known to be strongly positive in endometrioid adenocarcinoma of primary endometrial origin, its expression in ovarian counterpart has not been analyzed in detail. We assess the diagnostic value of vimentin expression in resolving these diagnostic scenarios.
Design: Immunohistochemistry with anti-vimentin antibody was performed on whole tissue sections from endometrioid adenocarcinoma 1) confined to endometrium (n=25), 2) metastatic from endometrium to distant sites (n=14), 3) involving endometrium and ovary and thought to be synchronous primaries (n=5), 4) metastatic from endometrium to ovary (n=7), 5) metastatic from ovary to endometrium (n=5), 6) metastatic to regional lymph nodes (n=10), and 7) tissue microarrays of 91 primary endometrial and 23 primary ovarian endometrioid carcinomas (pan-stage). Vimentin expression was semiquantitatively scored as negative, weak/moderately and strongly positive.
Results: Table 1 summarizes the results of vimentin expression. Vimentin was negative in 98% (38/39) of primary ovarian endometrioid carcinoma irrespective of whether or not they were associated with an endometrial tumor. In contrast, 84% of primary endometrial carcinomas were vimentin-positive. Five cases with double primary tumors were positive in endometrial tumors and negative in ovarian counterparts. The pattern of vimentin expression in the endometrioid tumors was maintained in their respective distant metastases. All normal endometrial glands strongly expressed vimentin. No correlation was identified between vimentin staining and tumor grade or clinical stage.

Conclusions: Ovary and endometrial endometrioid adenocarcinomas have different patterns of vimentin expression with high sensitivity (97%), specificity (84%) and negative predictive value (99%). As such, vimentin expression may be an excellent diagnostic tool in differentiating endometrioid adenocarcinomas of primary endometrial from primary ovarian origin, and for diagnosing double primary tumors.
Category: Gynecologic & Obstetrics

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 118, Tuesday Morning


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