Substantial shrinkage of adenomas cosecreting growth hormone and prolactin with use of cabergoline therapy.

Objective: To present 2 cases of patients with acromegaly and severe hyperprolactinemia whose primary therapy with cabergoline resulted in hormonal normalization and a considerable reduction in the size of their somatotroph macroadenomas.

Methods: We summarize the clinical presentation and the pertinent laboratory findings in 2 patients with acromegaly, as well as their clinical response to the therapy with cabergoline. A review of the literature regarding the use of cabergoline in acromegaly is also presented.

Results: A 48-year-old man (case 1) and a 26-year-old woman (case 2) were found to have acromegaly associated with very high levels of serum prolactin (2,700 and 5,250 ng/mL, respectively). These patients received first line therapy with cabergoline that resulted not only in clinical improvement and normalization of growth hormone, prolactin, and insulin-like growth factor-I levels but also in a substantial reduction in the size of their somatotroph macroadenomas. By 6 months after the patients began to take cabergoline, tumor shrinkage of 94% (in case 1) and of 70% (in case 2) was demonstrated by magnetic resonance imaging.

Conclusion: Our findings demonstrate that cabergoline should be considered for medical treatment of adenomas cosecreting growth hormone and prolactin, even in the presence of large tumors with appreciable suprasellar extension, because substantial tumor shrinkage is possible with this therapy.