INS and polycystic ovary syndrome: Hyperplasia of ovarian theca cells seems to be the most likely explanation, which would suggest that PCOS belongs to a spectrum of abnormal reactivity of the ovary to human Chorionic Gonadotrophin (hCG) stimulation along with luteoma and luteinic cyst of pregnancy.  Insulin resistance could worsen hyperandrogenism but is not enough to explain virilization.