Diagnosis of prolactin-secreting pituitary microadenoma.

Four women with secondary amenorrhea associated with hyperprolactinemia were studied. Baseline hormonal evaluation, including serum FSH, serum LH, TSH, T3, T4, and plasma cortisols were normal. Plain sella turcia x-rays were also normal. Prolactin-secreting pituitary microadenomas were found in all of the patients only after further diagnostic studies were done. These studies included polytomography of the sella turcia, dynamic pituitary testing of growth hormone reserve, ACTH reserve, gonadotropin reserve, and prolactin suppression with L-dopa. The early diagnosis of a small prolactin-secreting adenoma may be possible if several diagnostic criteria are ulilized. The most sensitive techniques available are: (1) polytomography, (2) the magnitude of plasma prolactin evaluation, and (3) the failure of suppression of prolactin secretion with L-dopa. Our findings emphasize the importance of an extensive evaluation of all women with amenorrhea associated with hyperprolactinemia.