Diploid/triploid mosaic placenta with fetus. Towards A better understanding of 'partial moles'.

We describe a case of partial molar change in a placenta that was associated with a normal female fetus who died in utero. The analysis of molar and normal placental tissue, as well as the karyotypic study of amnionic fluid indicate a complex origin of this conceptus. We review the possible mechanisms leading to this pregnancy and the general topic of partial hydatidiform mole. The formation of moles is complex and it is not easily divisible into so-called partial and complete hydatidiform moles. Rather, individual genetic study is needed to make an accurate diagnosis because macroscopic or microscopic examination alone fails to assess the complexity of these entities.