[1016] Histologic Patterns of Recurrent Endometrial Carcinoma.

Matthew Cesari, Douglas A Levine, Stephanie Wethington, Narciso Olvera, Daniel J Chiappetta, Karuna Garg, Robert A Soslow. Memorial Sloan-Kettering Cancer Center, New York, NY

Background: As targeted therapeutic agents are tested in recurrent endometrial carcinoma (REC), one cannot assume that patients with recurrence would benefit from targeted therapy based on evaluation of primary tumors. As part of a study evaluating the histologic, immunohistochemical (IHC) and genotypic (GEN) features of primary and REC, we first examine the histologic patterns of recurrence in this disease.
Design: Cases were identified (years 1999-2010) for which tissue blocks were available for both primary carcinomas and their recurrence(s). H&E-stained slides from the primary tumor and recurrence(s) were independently and randomly reviewed for histologic type and FIGO grade. The findings were considered discordant if any single pairing showed differences in either histologic type or FIGO grade.
Results: 31 primary tumors were identified with 39 recurrences. 24 (77%) cases included one recurrence and seven (23%) cases had multiple recurrences. Table 1 summarizes the histologic features of both primary and recurrent endometrial carcinomas. Concordant histology was seen in 20 (65%) cases; 11 (35%) cases were discordant. Two (66%) FIGO I endometrioid carcinomas were FIGO II at recurrence, while one appeared to recur as a tumor with ovarian-like low-grade serous morphology. Four (57%) FIGO II endometrioid carcinomas showed FIGO III (n=3) or ambiguous (n=1) histology at recurrence. One (25%) case, thought to represent FIGO III endometrioid carcinoma, recurred as serous carcinoma. Three (21%) serous carcinomas recurred as tumors with endometrioid patterns (n=2) or undifferentiated (n=1) carcinoma. All three primary carcinomas with ambiguous histology remained so at recurrence.

Histologic features of primary and recurrent endometrial carcinoma
FIGO I3/141/18
FIGO II7/148/18
FIGO III4/149/18

Conclusions: In about one third of cases, REC appears histologically different than the primary. Tumor progression or sampling error may account for recurrence morphology of FIGO I endometrioid carcinoma. In high grade carcinomas, morphology is protean and recurrences often do not closely resemble primary tumors. If morphology is linked to immunophenotypic and genotypic features, then primary histology may not be predictive of histology or response to targeted therapy at recurrence. If these preliminary findings were to be confirmed by GEN and IHC studies, then sampling/removal of REC may be required for better determination of eligibility for targeted therapy.
Category: Gynecologic & Obstetrics

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 159, Wednesday Afternoon


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