Idiopathic hyperprolactinemia with tumoral prolactin levels

The causes of hyperprolactinemia are varying, from physiological to pharmacological and pathological causes; but some cases are classified as “idiopathic” because of unknown causes. We describe a 29-year-old woman who presented to our department with galactorrhea and secondary amenorrhea. She had no clinical features of hypopituitarism and was not taking any medication. On physical examination, she had bilateral galactorrhea. Prolactin (PRL) level was high, up to 200 ng/ml, and other pituitary and thyroid indices were normal, including testing for macroprolactinemia. Pituitary magnetic resonance imaging was normal; and thoraco-abdominopelvic tomography was performed with no abnormalities detected. Cabergoline was started at the dose 0.5 mg/week. Galactorrhea disappeared, the menstrual cycle had become regular, and PRL level decreased to 26 ng/ml. Should all causes of hyperprolactinemia be ruled out and pituitary imaging revealed as negative, idiopathic hyperprolactinemia is therefore diagnosed. In symptomatic patients, treatment with dopaminergic agonists is indicated.