Galactorrhea. There are many causes of galactorrhea, and one is a pituitary adenoma (perhaps very small) that makes too much prolactin. Prolactin is the milk producing hormone that is naturally high post partum. A prolactinoma often causes menstrual disturbances. Sometimes these tumors can get large (>10 mm). The treatment is usually medical, not surgical, using Cabergoline or bromocriptine.