Pathologic classification of products of conception that are obtained from patients with unexplained pregnancy loss contributes significantly to clinical management. Distinction of hydropic abortus, partial hydatidiform mole, and complete hydatidiform mole can be impossible when based on morphology alone, yet these entities have different risk for persistent gestational trophoblastic disease. The combination of paraffin immunohistochemistry for p57 protein and FISH testing for aneuploidy can have great utility in facilitating these distinctions. One advantage to paraffin-based testing is that interpretation is directed to low-incident morphologic abnormality in a background of more abundant normal tissues.
Complete hydatidiform moles are characteristically androgenetic diploid (two paternal chromosomes). Partial hydatidiform moles are triploid (two paternal and one maternalchromosome), and non-molar products of conception are diploid (one paternal and one maternal chromosome). Complete moles demonstrate loss of both villous stromal and cytotrophoblast p57 staining, in contrast to partial moles and non-molar tissues. Recent publications suggest paraffin-based, combined p57 and FISH aneuploidy testing of products of conception that are morphologically suspicious for molar pregnancy.
Kipp BR et al. 2010 Feb. Comparison of fluorescence in situ hybridization, p57 immunostaining, flow cytometry, and digital image analysis for diagnosing molar and nonmolar products of conception. Am J Clin Pathol. 133(2):196-204.
I P57 and I P57 TC by Immunohistochemistry and Aneuploidy by FISH [F ANEU] for FFPE specimens now available at MPLN.