Primary amenorrhea and pseudoprolactinoma in a patient with primary hypothyroidism. Reversal of clinical, biochemical, and radiologic abnormalities with levothyroxine.

A 15-year-old girl presented with primary amenorrhea, galactorrhea, hyperprolactinemia and an enlarged pituitary gland. She proved to have primary hypothyroidism. Therapy with levothyroxine resulted in prompt induction of regular menses, normalization of hormone levels, and a reduction in the size of the pituitary. Although hypothyroidism is known to produce secondary amenorrhea, hyperprolactinemia, and pituitary enlargement, this is believed to be the first computed tomographic documentation of such a "pseudoprolactinoma" presenting as primary amenorrhea.