Acromegaly: Underdiagnosed in Patients with Prolactinoma

Prolactin secreting adenomas are very common and account for 50-60% of all functional pituitary adenomas. Medical history pertaining to reproductive and sexual function initiates the work up for prolactinoma. At the time of initial assessment other pituitary hormones may be evaluated, including growth hormone (GH). Thereafter, patients are treated medically with dopamine agonist, typically with no further assessment of GH hypersecretion. Review of the literature suggests that up to 4% of patients with an established diagnosis of prolactinoma can develop acromegaly even after many years of the initial evaluation. Acromegaly is a rare disease with mortality rates 23 times higher as compared to that of the general population. The interval from onset of symptoms to the diagnosis may range from one year to several decades. Thus, omitting IGF-1 measurements at the initial evaluation of prolactinoma, and/or in the follow up period, can miss mild and subtle cases of acromegaly. Therefore, biochemical evaluation for GH excess should be considered in patients with prolactinoma initially as well as in the remote follow up.