Introduction Prolactin-secreting adenomas are the most common pituitary tumors and a common cause of pathological hyperprolactinemia. Prolactinomas are classified according to their size: microprolactinomas are <1 cm in diameter and macroprolactinomas range from 1 to 4 cm. Giant prolactinomas are > 4cm. Giant prolactinomas are rare and account for only 1-5 % of all prolactinomas. In giant prolactinomas, the prolactin levels are usually between 1,000-100,000 ng/mL. They may be locally aggressive leading to visual damage and ophthalmoplegia. The typical clinical manifestations in men include hypogonadism, erectile dysfunction, visual symptoms, weakness, and headaches. Women usually present amenorrhea, headaches, visual dysfunction, and galactorrhea. Treatment goals include normalizing hormonal levels and promoting tumor shrinkage with dopamine agonists. Surgery and radiotherapy may be considered for refractory cases.