Most common hypothalamus-pituitary tumor followed by primary or secondary amonorrhea is craniopharygioma which mainly arises form upper sella area and also have one or more neurologic symptoms such as deteriorating vision and severe headache. Decreased GnRH secretion due to stalk compression may result in panhypopituitarism. Unlike other pituitary hormones, prolactin secretion is mainly controlled by potent negative inhibition of hypothalamic dopamine. Large sella masses or traumatic injuries are common causes of hyperprolactinemia of broken dopamine regulation. A 19-year-old woman presented to us in gynecologic out patient department with history of amenorrhea for 14 months. She was a virgin, had no medical history. From the menarche stared 6 years ago, her menstruation cycle had been about two-month till the menstruation stopped a year ago. She said she gained 10kg for a year. Trans-rectal ultrasonography of pelvis showed small uterus 37x20mm, polycystic ovaries. Endometrial thickness was 2mm. On a blood test taken at a local clinic 2 months ago, LH (Luteinizing Hormone) 0.4mIU/mL, FSH (Follicle Stimulating Hormone) 2.0mIU/mL, E2 (Estradiol)<10pg/mL, TSH (Thyroid Stimulating Hormone) 1.0IU/mL, Prolactin 54.3ng/mL were checked. Re-checked prolactin level at our clinic was 58.78ng/mL. Under the diagnosis of hypogonadotropic hypogonadism, clomiphene 50mg for 5 days and carbegoline 0.5mg once in a week were prescribed. Finally the drug was stopped in fifteen months because the prolactin was lowered to 3.62ng/mL despited reducing the dosage to 0.125mg per two weeks. But the prolactin level rose to 122.80ng/mL just in eight weeks after stopping the drug. Because the prolactin level was too high, brain MRI (Magnetic Resonance Imaging) was done immediately, which demonstrated a 31x24x16mm delayed enhancing and cystic lesion in sellar and suprasellar area, probably craniopharyngioma. Acknowledgements: This work was supported by the Soonchunhyang University Research Fund