Amenorrhea-galactorrhea due to occult hypothyroidism

A 25-year-old woman with galactorrhea, oligomenorrhea, hyperprolactinemia, and CT evidence of pituitary enlargement had transsphenoidal microsurgery with initial resolution of hyperprolactinemia, but persistent oligomenorrhea and galactorrhea. In retrospect, she had biochemical evidence of primary hypothyroidism before operation, despite being clinically euthyroid. Administration of thyroid hormone resulted in resolution of the pituitary enlargement and the symptoms.