hydatidiform mole

https://doi.org/10.1351/goldbook.10812

Vesicular or polycystic mass resulting from the proliferation of the trophoblast, with hydropic degeneration and avascularity of the chorionic villi.

Note: The abnormal tissue typically results from gene expression from paternally derived chromosomes and a loss of maternal chromosomes.
Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 765 [Terms] [Paper]