Is it posible to have a molar in placenta during pregnancy?

Are you talking about a molar pregnancy?

http://www.google.ca/url?sa=t&rct=j&q=molar+in+placenta&source=web&cd=1&ved=0CE0QFjAA&url=http%3A%2F%2Fwww.americanpregnancy.org%2Fpregn ancycomplications%2Fmolarpregnancy.html%2F&ei=HsgpUJfRM8rtigKt5IDoAg&usg=AFQjCNHIzPQN3Hj1400avb5vDyF6-u5GJA&cad=rja

If so, yes, it's possible, but very rare.