Is insulin growth factor-1 (IGF-1) playing a role for aneurysm formation in patients with pituitary gland tumor?

The combination of pituitary gland tumor and aneurysmal disease has previously been described. Most of these aneurysms have affected intracranial arteries. The purpose is to present 2 patients with thoracoabdominal aortic aneurysm and pituitary gland tumor and further to discuss the mechanism behind this combination of diseases. A 59-year-old male patient was admitted with abdominal pain and a 120 mm thoracoabdominal aortic aneurysm type III. He was operated with resection and graft replacement. During the operation, it was noted that his intra-abdominal arteries were extremely enlarged. The diagnosis acromegaly was confirmed in the late 50's and he had received irradiation therapy and underwent partial trans-sphenoidal hypophysectomy. His growth hormone values eventually declined while he had elevated insulin growth factor-1 (IGF-1) levels. The patient died from stroke 6 years after operation. Patient n. 2 is a 73-year-old female with a type II thoracoabdominal aortic aneurysm. She was operated for a pituitary adenoma in 1988. There were no clinical or biochemical signs of acromegaly. However, she had elevated serum values of IGF-1. The maximum diameter of the aneurysm was 60 mm. Because of comorbidity the patient has been followed at the outpatient clinic. The mechanism behind the combination of pituitary gland tumor and aneurysm is obscure. One of our patients had classical acromegaly. Growth hormone decreased over the years, while his IGF-1 values were normal or elevated. The other patient had increased levels of IGF-1 without typical acromegaly. This might indicate that IGF-1 could play a role in the development of aneurysm in patients with pituitary tumor. This combination of diagnoses should be kept in mind when dealing with patients having aneurysmal disease.