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

Area of Science:

• Reproductive Medicine
• Pathology
• Genetics

Background:

• Hydatidiform moles (HM) are gestational trophoblastic diseases characterized by abnormal chorionic villi and trophoblastic hyperplasia, stemming from genetic material imbalances.
• The differential diagnosis for HM includes androgenetic/biparental mosaic/chimeric (ABMC) conceptions, which present with both molar and non-molar forms.

Observation:

• ABMC conceptions involve a mix of androgenetic and biparental cell populations, arising from zygotic errors like mosaicism or chimerism.
• These rare lesions exhibit distinct features such as multiple villous populations, discordant p57 immunostaining, and mixed genotypes.

Findings:

• This report details two cases of ABMC conceptions with molar components in pregnant patients presenting with ultrasound findings suggestive of HM.
• Diagnostic challenges include differentiating ABMC from complete HM, necessitating advanced techniques.

Implications:

• Accurate diagnosis of ABMC conceptions, particularly the molar form, is vital due to the risk of persistent gestational trophoblastic disease, requiring appropriate management.
• Utilizing ancillary techniques like p57 immunohistochemistry, FISH, and genotyping aids in precise identification, though diagnostic pitfalls remain.