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Updated: Jun 4, 2026
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Microsatellite DNA Genotyping and Flow Cytometry Ploidy Analyses of Formalin-fixed Paraffin-embedded Hydatidiform Molar Tissues
Published on: October 20, 2019
Hydatidiform moles: ancillary techniques to refine diagnosis
Brigitte M Ronnett1, Cheryl DeScipio, Kathleen M Murphy
1Department of Pathology, The Johns Hopkins University School of Medicine and Hospital, Baltimore, Maryland, USA. bronnett@jhmi.edu
Summary
Accurate diagnosis of hydatidiform moles (CHM, PHM) and nonmolar specimens is crucial for patient management. Molecular techniques like p57 immunostaining and genotyping improve diagnostic accuracy beyond morphology.
Area of Science:
- Gynecologic Pathology
- Reproductive Genetics
- Trophoblastic Disease Diagnosis
Background:
- Morphological diagnosis of hydatidiform moles (complete hydatidiform mole [CHM], partial hydatidiform mole [PHM]) and nonmolar specimens has poor interobserver reproducibility.
- Accurate distinction is vital due to differing risks of persistent gestational trophoblastic disease and distinct clinical management strategies.
Purpose of the Study:
- To review current challenges in hydatidiform mole diagnosis.
- To highlight the utility of molecular techniques in refining diagnosis and assessing associated risks.
- To discuss an algorithmic approach for routine diagnostic practice.
Main Methods:
- Immunohistochemical analysis of p57 expression (evaluating maternal and paternal gene imprinting).
- Short tandem repeat (STR) genotyping to determine the parental origin of alleles.
- Integration of molecular findings with morphological assessment.
Main Results:
- p57 immunostaining effectively identifies CHMs by detecting the absence of maternal DNA.
- STR genotyping can differentiate between CHMs (androgenetic diploidy), PHMs (diandric triploidy), and nonmolar specimens (biparental diploidy).
- An algorithmic approach combining morphology and molecular techniques enhances diagnostic accuracy.
Conclusions:
- Morphological assessment alone is insufficient for accurate hydatidiform mole subclassification.
- Molecular techniques, particularly STR genotyping, are essential for definitive diagnosis.
- Refined diagnosis ensures appropriate risk assessment and clinical management of gestational trophoblastic disease.
