Galactorrhoea and pituitary mass: a typical prolactinoma?

A 21 year bid woman presenting with galactorrhoea, hyperprolactinaemia, and a pituitary mass on magnetic resonance imaging ((MRI) is described who was referred to us before planned pituitary surgery. Although a thorough histo ry did not suggest hypothyroidism, laboratory studies revealed profound pri mary hypothyroidism, At that time, pituitary MRT showed homogeneous enlarge ment of the pituitary gland consistent with pituitary hyperplasia due to pr imary hypothyroidism, With thyroid hormone replacement therapy the galactor rhoea resolved, concentrations of prolactin and thyroid hormones returned t o normal, and the pituitary shrunk to normal size within two months. This c ase illustrates that primary hypothyroidism can present only with galactorr hoea and pituitary mass, and should therefore be considered in the differen tial diagnosis of hyperprolactinaemia and pituitary enlargement.