ACTH silent adenoma shrinking under cabergoline

Objectives: The authors present a case report that proposes the use of cabe rgoline treatment in silent ACTH adenoma, an unusual member of the heteroge neous group of the so-called clinically nonfunctioning pituitary adenomas. Design: Following the clinical and radiological improvement of a recurrent silent ACTH adenoma in a 77-year-old patient treated with cabergoline (0.5 mg every 2 days for 2 years), in vitro studies of the original turner were performed, Methods: The original tumor from the patient was studied by in situ hybridi zation and dopamine D2 receptor autoradiography. It was compared with four macroprolactinomas and two macroadenomas from patients with Gushing's disea se. Results: The D2 receptor mRNA signal of the reported case was intense and o f the same order of magnitude as that observed in control prolactinomas. Do pamine D2 receptor autoradiography was twice that of control corticotroph a denomas and was close to that observed in prolactinomas. Conclusions: This is the first description of an in vivo shrinkage of an AC TH silent adenoma under cabergoline. We demonstrate in vitro, the presence of D2 receptors in the primitive tumor in concentrations similar to those f ound in control prolactinomas. These results suggest that therapeutic trial s with cabergoline might be undertaken in recurring cases of ACTH silent tu mors and more generally, non-functioning pituitary adenomas.