Prolactinopituitary tumors, also known as pituitary lactinomas, can vary greatly in size, from small tumors less than 10 mm in diameter to larger ones larger than 10 mm in diameter, and with this value, pituitary lactinomas can be divided into pituitary lactin microadenomas and pituitary lactin macroadenomas. If the size can increase further, even to a diameter of 4 cm or more, it is called a pituitary lactin macroadenoma. Depending on the size, the treatment may vary. Microadenomas are usually treated with medication or minimally invasive surgery. However, larger pituitary lactinomas will most likely require open surgery, which is more invasive than minimally invasive surgery.