[1146] Differential Diagnosis between Early Complete and Partial Mole Using TSSC3 and P57 (Kip2) Antibodies: Correlation with DNA Ploidy

Masaharu Fukunaga. Jikei University Daisan Hospital, Komaeshi, Tokyo, Japan

Background: The differentiation of complete mole (CM), aberrant androgenetic conceptus, from partial mole (PM) and hydropic abortion (HA) in early gestation is very important for patient management. TSSC3 and p57 (Kip2) (p57) are products of a paternally imprinted, maternally expressed gene.
Design: Ten diploid voluntary artificial abortions (ABs), 20 diploid HAs, 20 triploid PMs, and 44 diploid CMs (including 4 persistent diseases), all of which were in the first trimester, were evaluated by immunohistochemistry of formalin-fixed tissues using monoclonal antibodies against p57 and TSSC3. p57 and TSSC3 are coded by different genes. DNA ploidy in all cases was analyzed by flow cytometry using formalin-fixed, paraffin-embedded block sections.
Results: In all diploid ABs, nuclear p57 was strongly expressed in cytotrophoblasts, villous and extravillous intermediate trophoblasts, villous stromal cells, and decidual stromal cells, but was absent in syncytiotrophoblasts. TSSC3 was only expressed in cytotrophoblasts. In diploid CMs, p57 expression in cytotrophoblasts and villous stromal cells was either absent (37 cases) or very low (7 cases). Villous intermediate trophoblasts stained for p57 in 12 cases of CM. TSSC3 was completely negative in these trophoblasts and villous stromal cells in all CMs. On the other hand, all diploid HAs and all triploid PMs showed TSCC3 levels comparable to the findings observed in diploid ABs. 16 diploid HAs and 19 triploid PMs expressed p57 positivity in cytotrophoblasts and villous stromal cells. The remaining 4 diploid HAs and one triploid PM with the lack of p57 staining exhibited typical histologic features of HA or PM. Decidual stromal cells provided a reliable internal control for p57, but there was no internal control for TSSC3.
Conclusions: The findings support the hypothesis that misexpression of p57 and TSSC3 is involved in the abnormal development of androgenetic CMs. The immunohistochemical results were highly concordant with the DNA ploidy status. Immunohistochemical analysis is a useful tool for the differential diagnosis of CMs versus PMs and HAs, and TSSC3 is more sensitive than p57. Since the immunohistochemical diagnosis of CM is based on a negative result, the absence of staining, the use of both markers (p57 and TSSC3) together could increase the level of confidence when making this prognostically important distinction.
Category: Gynecologic & Obstetrics

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 135, Tuesday Morning


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