The clinical features of 20 patients from five families with multiple endocrine neoplasia syndrome type I (MEN-I) were studied. Nineteen patients (95%) had hyperparathyroidism. Five patients who had a diagnosis during surgery of adenoma and who had fewer than 3.5 glands removed had recurrence of hypercalcemia after surgery. Fourteen patients (70%) had pancreatic islet cell tumors. All had one or more elevated serum polypeptide hormones, and six had symptoms related to the hormones produced. Multiple pancreatic tumors were identified in the nine patients who underwent surgery. Three patients who died had a mean survival of 6.3 +/- 2.9 years. Eight patients had pituitary tumors; seven had macroadenomas. Of the eight patients with pituitary tumors, seven had high serum prolactin and responded to bromocriptine therapy, whereas the eighth patient had acromegaly treated with radiotherapy. It was concluded that hypercalcemia due to hyperparathyroidism in MEN-I syndrome patients should be managed by a resection of four glands and transplantation of one half gland into the forearm because none of the patients has shown evidence of a recurrence, and serum calcium levels have been normal. Pancreatic tumors, which are usually multiple, may be asymptomatic. Patients with these tumors usually have long survival rates, even with distant metastasis. Total pancreatectomy may be the method of choice, especially in patients with gastrinoma caused by the diffuse nature of the disease. Long-term follow-up is needed, however, with more patients. Pituitary tumors are primarily prolactin-producing tumors, and medical treatment is the method of choice.
