Rosiglitazone in Treating Patients With Pituitary Tumors

Inclusion Criteria: * Clinically demonstrable pituitary tumor, including either of the following subtypes: * ACTH-secreting adenoma * Residual or recurrent disease ≥ 1 month after prior pituitary surgery * Clinically demonstrable tumor, as evidenced by both of the following: * Elevated 24-hour urinary free cortisol (UFC) level * Lack of suppression of 8 a.m. serum cortisol to \< 1.8 µg/dL after administration of dexamethasone 1 mg at 11 p.m. the previous night * Tumor demonstrated by MRI performed with and without contrast and/or by inferior petrosal sinus sampling with evidence of a central ACTH source. * Normal visual field evaluation by Goldman perimetry * Hypopituitarism allowed as evidenced by any or all of the following: * Subnormal growth hormone (GH) response to arginine/GH-releasing hormone testing (normal response is an increase of 2-6 ng/me) * Low age and sex-matched IGF-1 levels * Low thyroid-stimulating hormone, free triiodothyronine, and free thyroxine levels * Low estradiol levels * Low leuteinizing hormone (LH) and low follicle-stimulating hormone (FSH) levels in post-menopausal female patients OR low testosterone, LH, and FSH levels in male patients * Patients with Cushing disease (i.e., harboring ACTH-secreting pituitary adenomas) must meet the following criteria: * Hypercortisolemic (i.e., uncured) despite ≥ 1 pituitary surgery * Refuse to undergo pituitary irradiation and/or bilateral adrenalectomy * Refuse alternate steroid-lowering therapy…