ABSTRACT
A 15-year-old boy with idiopathic hyperprolactinemia is described. He was markedly obese, in early puberty, and had gynecomastia and galactorrhea. Serum prolactin level was high, up to 220 pg/ml. Thyroid function test was normal. Idiopathic hyperprolactinemia was diagnosed on the basis of elevated prolactin level, and no demonstrable pituitary tumor was revealed by computerized tomography brain scan and magnetic resonance imaging. Bromocriptine was started initially at the dose 2.5 mg/day, then increased to 7.5 mg/day. Galactorrhea disappeared and prolactin level decreased to < 10 ng/ml. A review of the literature indicates that idiopathic hyperprolactinemia in adolescent males is extremely rare. To our knowledge, this patient is the youngest reported case of hyperprolactinemia in Thailand.