Placental Molar Disease

Abstract

The molecular cytogenetic analysis of specimens (genotyping) suspicious for hydatidiform mole (HM) significantly improves diagnostic accuracy over histopathology and immunohistochemical analysis alone, particularly in the classification of partial mole. However, the implementation of this advance in diagnostics has been slow. This study sought to identify the major benefit and potential barriers to the adoption of genotyping. A pilot Placental Molar Diagnostic (PMD) Service was established combining histopathology, p57 immunohistochemistry, and molecular genotyping analysis for both in-house and referred-in cases suspicious for HM or with a preliminary diagnosis of HM. A retrospective analysis of 117 cases received in the first 16 mo was conducted to identify the utility of the PMD Service and factors or barriers which precluded optimal results. A final diagnosis of HM was made in 73 cases (37 complete HMs and 36 partial HMs). The remaining 44 cases were hydropic abortuses. Three potential barriers were identified that could lead to less than optimal results from a PMD Service: prevalence of noninformative genotyping, lack of any available or appropriate paraffin blocks, and inappropriate deferral of genotyping. The major utility of this pilot PMD Service was to increase the specificity of a diagnosis of HM, and avoid unnecessary clinical follow-up in 37% of cases with an initial suspicion or diagnosis of HM. Measures can be undertaken to address potential barriers to the implementation of a comprehensive placental diagnostic platform. Underutilization of molecular genotyping in the diagnosis of HM likely leads to inappropriate management and "downstream" costs in a significant proportion of patients suspected of having HM.

Clinical presentation and treatment outcome of molar pregnancy: Ten years experience at a Tertiary Care Hospital in Dammam, Saudi Arabia

“…HM can be complete or partial: Complete mole (CM) accounts for the majority of HM which develops when either 1 or 2 sperm cells fertilize an egg containing a nucleus or DNA, with no identifiable fetus, whereas the partial mole contains some fetal tissue but no viable fetus. [12]…”

Androgenetic/Biparental Mosaic/Chimeric Conceptions With a Molar Component: A Diagnostic and Clinical Challenge

“…QF-PCR analysis (Aneufast QF-PCR kit, Genomed AG, Switzerland) to assess genotype as well as numerical abnormalities for chromosomes 13, 18, 21, and sex chromosomes was carried out on unstained 10 µm-thick formalin-fixed paraffin-embedded tissue sections. The details of this process have been described elsewhere (11) but briefly, a pathologist marked maternal tissue (i.e. decidua and/or endometrium) on a hematoxylin and eosin-stained slide as well as the chorionic villi with the 3 different areas of p57 immunohistochemical staining (discordant p57 staining, complete lack of p57 staining, and normal p57 expression pattern).…”