A hydatidiform mole is a pregnancy/conceptus in which the placenta contains grapelike vesicles (small sacs) that are usually visible to the naked eye. The vesicles ...MolarpregnancyFromWikipedia,thefreeencyclopediaJumptonavigationJumptosearchAbnormalformofpregnancy(humandisorder)MolarpregnancyOthernamesVesicularmole,Hydatidmole,HydatidiformmoleHistopathologicimageofhydatidiformmole(completetype).H&Estain.SpecialtyObstetricsMolarpregnancyisanabnormalformofpregnancyinwhichanon-viablefertilizedeggimplantsintheuterusandwillfailtocometoterm.Amolarpregnancyisagestationaltrophoblasticdisease[1]whichgrowsintoamassintheuterusthathasswollenchorionicvilli.Thesevilligrowinclustersthatresemblegrapes.[2]Amolarpregnancycandevelopwhenafertilizedeggdoesnotcontainanoriginalmaternalnucleus.Theproductsofconceptionmayormaynotcontainfetaltissue.Itischaracterizedbythepresenceofahydatidiformmole(orhydatidmole,molahydatidosa).[3]Molarpregnanciesarecategorizedaspartialmolesorcompletemoles,withthewordmolebeingusedtodenotesimplyaclumpofgrowingtissue,oragrowth.Acompletemoleiscausedbyasinglesperm(90%ofthetime)ortwo(10%ofthetime)spermcombiningwithaneggwhichhaslostitsDNA.Inthefirstcase,thespermthenreduplicates,forminga"complete"46chromosomeset.[4]Thegenotypeistypically46,XX(diploid)duetothesubsequentmitosisofthefertilizingspermbutcanalsobe46,XY(diploid).[4]46,YY(diploid)isnotobserved.Incontrast,apartialmoleoccurswhenanormaleggisfertilizedbyoneortwospermwhichthenreduplicatesitself,yieldingthegenotypesof69,XXY(triploid)or92,XXXY(tetraploid).[4]Completehydatidiformmoleshavea2–4%riskofdevelopingintochoriocarcinomainWesterncountriesand10–15%inEasterncountriesanda15%riskofbecominganinvasivemole.Incompletemolescanbecomeinvasive(<5%risk)butarenotassociatedwithchoriocarcinoma.[4]Completehydatidiformmolesaccountfor50%ofallcasesofchoriocarcinoma.Molarpregnanciesarearelativelyrarecomplicationofpregnancy,makingup1in1,000pregnanciesintheUS,withmuchhigherratesinAsia(e.g.upto1in100pregnanciesinIndonesia).[5]Conte