A somatotropin-producing pituitary adenoma with an isolated adrenocorticotropin-producing pituitary adenoma in a female patient with acromegaly, subclinical Cushing's disease and a left adrenal tumor.

A 67-year-old female with hypertension and impaired glucose tolerance was admitted to our hospital because of a typical acromegalic appearance, including large, thickened bulky hands and feet, and a large prominent forehead and tongue. She did not have a Cushingoid appearance, such as a moon-face, buffalo hump, purple striae or central obesity. The laboratory data revealed a serum GH level of 4.6 ng/mL and serum insulin-like growth factor-1 level of 811 ng/mL. The oral glucose tolerance test showed no suppression of the GH values. An endocrine examination showed a lack of circadian rhythmicity of ACTH and cortisol. Cortisol was not suppressed by a low dose of dexamethasone during the suppression test, but was suppressed by a high dose of dexamethasone. A radiological study revealed two isolated adenomas in the pituitary and a left adrenal tumor. These findings strongly suggested a diagnosis of acromegaly with subclinical Cushing's disease and a left adrenal incidentaloma. Transsphenoidal surgery was performed. Hematoxylin and eosin staining showed that the left and right pituitary adenomas were composed of basophilic and acidophilic cells, respectively. Immunohistochemical staining showed the left adenoma to be positive for ACTH and negative for GH. In contrast, the right adenoma was GH-positive and ACTH-negative. This is a rare case of independent double pituitary adenomas with distinct hormonal features. We also provide a review of the previously reported cases of double pituitary adenomas and discuss the etiology of these tumors.