Milky discharge from nipple. is that a tumor?

Nipple milk discharg: True galactorrhea, milk secretion from the breast, can be caused by excessive prolactin production from the pituitary - usually a small tumor or microadenoma. If the prolactin is high an MRI of the pituitary will be needed. Several drugs can increase prolactin levels, particularly tranquillizers. Also need to rule out under active thyroid with TSH measurement as this can increase prolactin levels.