[972] Chromosome In Situ Hybridization To Differentiate Early Partial Hydatidiform Mole from Hydropic Abortus: A Validation Study

AK Folkins, LZ Cruz, DP Goldstein, RS Berkowitz, CP Crum, DW Kindelberger. Brigham and Women's Hospital, Boston, MA

Background: The distinction between partial hydatidiform mole (PM) and hydropic abortus (HA) has important implications for patient management. Immunohistochemical detection of p57kip2 protein has greatly facilitated the separation of early complete mole (CM) from HA, but no single technique has emerged that rapidly distinguishes early PM from HA. Flow cytometry, karyotype, and fluorescence in situ hybridization are expensive and require specialized equipment and expertise. Colorimetric chromosome in situ hybridization (CrISH) has recently been introduced as a possible alternative. The goal of the current study was to validate CrISH using a single chromosome 10 probe in triploid and diploid placentas.
Design: Fifty (50) hydatidiform moles and 25 hydropic abortuses characterized by flow cytometry were studied. De-paraffinized 5-micron sections were permiablized with Proteinase K and Triton X-100 and incubated with a biotin-labeled Chromosome 10 probe and visualized with 3,3'-diaminobenzidine and hydrogen peroxide according to standard protocols. The stained sections were independently evaluated by two observers (AKF and DWK). One hundred nuclei were scored for the number of signals. Gain in chromosome 10 was recorded when 15% or more of the nuclei of interest showed at least three (3) signals.
Results: Of the 50 hydatidiform moles, 22 were diagnosed as PM and 28 as CM. CrISH performed on the CM cases showed two signals in 25 cases and four signals in three. Twenty of 22 PMs (91%) contained three signals; two cases showed two signals. The concordance between CrISH and flow cytometry for the molar gestations was 96%. In the 25 cases of non-molar HA, CrISH studies revealed two (2) signals in 24 (96%). The remaining case had three signals. The overall agreement between the CrISH and flow cytometry was 96%.
Conclusions: CrISH using a single DNA probe is highly effective at differentiating between PM and CM and between PM and hydropic abortus. CrISH with a single DNA probe, used in combination with p57 immunohistochemistry, provides a simple, rapid, cost-effective means to exclude hydatidiform mole in the setting of HA.
Category: Gynecologic

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 158, Tuesday Afternoon