McCune-Albright syndrome and acromegaly: clinical studies and responses to treatment in five cases.

We report here five new patients with McCune-Albright syndrome and acromegaly. In the five patients studied (three males and two females aged 18-42 years), acromegaly began before the age of 20 years and was recognized after the diagnosis of fibrous dysplasia, which was polyostotic in three cases and monostotic in two. Bone fibrous dysplasia always involved the base of the skull and in four patients prevented surgical removal of the pituitary adenoma, which was visualized easily by magnetic resonance imaging. Serum growth hormone (GH) levels ranged between 20 and 48 micrograms/l and were not suppressed by an oral glucose load. Thyrotropin-releasing hormone administration produced a paradoxical increase in serum GH levels in all the patients. Four of the five patients had hyperprolactinemia (43-670 micrograms/l). In the sole patient who could be operated on, a typical adenoma with positive immunostaining for GH was incompletely removed and postoperative radiation therapy failed to cure the acromegaly. In two patients, medical therapy with bromocriptine and/or octreotide was partially or totally ineffective whatever the dose (up to 1.5 mg per day) and duration (2-4 years) of octreotide treatment.