Excessively high prolactin level in a patient with a nonprolactin-secreting adenoma. Case report.

The authors report the case of a 48-year-old woman who presented with a nonprolactin-secreting adenoma and a preoperative prolactin level of 662 ng/ml. The patient's neoplasm subsequently enlarged despite normalization of her prolactin level with dopamine agonist therapy. Hyperprolactinemia, with levels of prolactin as high as 150 ng/ml, is commonly associated with sellar tumors and is attributed to disruption of the normal delivery of dopamine to the adenohypophysis. The prolactin level found in this patient represents the highest level attributed to the stalk-section effect reported in the literature and underscores the need for repeated radiographic assessment of patients who are undergoing treatment with bromocriptine and have prolactin levels in the 25 to 1000 ng/ml range.