Could Polyp Cause Missed Periods Followed By Spotting?

my period was late it usualy comes on the 25th and it came on the 30th til the 6th october and i havent had sex and i been to the clinic because i started to get light spotting on the 18th of october and wasnt sure how because i havent had intercourse.. i was told i have a polyp. im really confused how did i get this?