Double pituitary adenomas: a series of three patients.

Multiple pituitary adenomas may occur in up to 1.6-3.3% of patients with Cushing's syndrome. We report three patients with double pituitary adenomas detected at surgery. Two patients had Cushing's disease, but trans-sphenoidal exploration revealed a small prolactinoma in each. One prolactinoma also contained small numbers of basophils. Re-operation in both patients because of persistent Cushing's syndrome showed an ACTH-secreting micro-adenoma. The third patient with acromegaly had two macro-adenomas discovered in different parts of the gland at surgery: one plurihormonal and one null cell tumour. Careful evaluation of pre-operative MRI may not always detect more than one pituitary adenoma.