Giant aneurysms of the sellar region simulating pituitary adenomas: a diagnosis to be considered.

Aneurysms of the sellar region are commonly mistaken for pituitary adenomas, since they have similar clinical, endocrinological and neurological symptoms. The authors describe three patients with giant aneurysms of the internal carotid artery which were initially diagnosed as pituitary tumors. In all patients the clinical presentation was nonspecific, and consisted mainly of neurological symptoms such as headaches and visual field defects. Endocrine abnormalities were also found in the three cases. Patient no. 1 had short stature, lack of GH response to clonidine stimulation, low IGF-1 levels and blunted TSH response to TRH. Patient no. 2 had gonadotropin deficiency and patient no. 3 had hyperprolactinemia. CT scans showed a densely enhanced lesion in all patients, which was heterogeneous in one case and homogeneous in the remaining. Carotid angiography confirmed the diagnosis of aneurysm. Preoperative angiographic studies are necessary for the differential diagnosis of an aneurysm from a pituitary tumor. Furthermore, these studies could prevent the serious consequences of a transsphenoidal surgical approach in misdiagnosed cases.