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Complete hydatidiform mole with a coexistent embryo
R N Baergen1, T Kelly, M J McGinniss
1Department of Pathology, UCSD School of Medicine, San Diego, CA 92103-8720, USA.
Human Pathology
|July 1, 1996
Summary
This study reports the first documented case of a complete hydatidiform mole coexisting with a viable embryo, confirmed by genetic analysis. The mole originated from a single sperm fertilizing an empty egg, despite initial signs of a normal pregnancy.
Area of Science:
- Reproductive Medicine
- Genetics
- Obstetrics
Background:
- Complete hydatidiform mole (CHM) is a placental abnormality typically arising from androgenetic fertilization of an anucleated egg.
- CHM usually results in early pregnancy loss and is associated with a risk of gestational trophoblastic neoplasia.
Observation:
- A 19-year-old woman presented with an early intrauterine pregnancy showing a gestational sac and fetal heart activity.
- Follow-up ultrasound revealed absence of embryonic structures and a pattern consistent with CHM.
- Histological examination confirmed a classic hydatidiform mole with a normal 46,XX maternal karyotype.
Findings:
- Molecular genetic analysis using variable number of tandem repeat (VNTR) probes demonstrated that the placental tissue contained only paternal DNA.
- The genetic profile indicated two genomic copies of each paternal allele, consistent with androgenetic origin.
- This genetic profile confirms the diagnosis of complete hydatidiform mole originating from an empty ovum fertilized by a single sperm.
Implications:
- This case presents the first documented instance of a complete hydatidiform mole coexisting with a living embryo, verified by comprehensive genetic analysis.
- It challenges previous assumptions about the non-viability of embryos in complete hydatiform moles.
- Further research may explore the mechanisms allowing embryonic survival in such genetic contexts and refine diagnostic criteria.