PRL and hyperprolactinemia: Invasive giant prolactinoma is one of the rare subtype of prolactin (PRL)-secreting pituitary neuroendocrine tumors (Pit-NETs), measuring > 40 mm, accounting for only 0.5% of all Pit-NETs, and 4.4% of all prolactinomas, often presenting with headaches, vision loss, hyperprolactinemia, hypopituitarism as the first clinical manifestations [1–3].