Benign and malignant tumors in patients with acromegaly.

Growth hormone and its principal mediator insulinlike growth factor I are known promoters of normal growth. To determine whether excessive secretion of growth hormone is associated with an increased occurrence of benign and of malignant tumors, we studied records of 87 patients with acromegaly seen in the Lahey Clinic Medical Center (Burlington, Mass) from 1957 to 1988 and compared the rate of tumor occurrence with a control group of patients with pituitary tumors (198) and with findings from a cancer registry. Patients with acromegaly had a 2.45-fold increased rate of malignant tumors (95% confidence interval, 0.98 to 5.04) compared with findings from the tumor registry. Female patients had a higher rate than male patients. The rate of carcinoma of the thyroid was excessive and previously underscribed, but the rate of carcinoma of the colon was not increased as reported by others. Among benign lesions, goiters, predominantly nodular, were seen in 25% of patients in addition to a large number of mesenchymal lesions.