Pituitary tumors and aneurysms: case report and review of the literature.

A case of acromegaly from a growth hormone-secreting pituitary adenoma associated with dilatation of all major intracranial arteries and bilateral giant, cavernous aneurysms is presented. Although saccular aneurysms are randomly associated with all types of pituitary tumors, the frequency of this happening with growth hormone-secreting or "chromophobe adenomas" is greater than would be expected by chance alone. Intrasellar saccular aneurysms contiguous with tumors have been reported. Bilateral cavernous carotid aneurysms have also occurred in association with pituitary tumors. Both infectious (bacterial and fungal) and traumatic aneurysms can develop as complications of pituitary surgery. A single case of aneurysms due perhaps to actual tumor infiltration of the arterial wall has been reported. Radiation therapy has rarely been associated with aneurysmal dilatation for nonpituitary tumors and has been reported only once after treatment of a pituitary tumor. Aneurysms may mimic pituitary tumors by producing endocrine disturbances, such as hypopituitarism, hyperprolactinemia, and diabetes insipidus, and by compressing adjacent cranial nerves. Anomalous large arteries, such as the trigeminal or transsellar-carotid variants, may run through the sella, and there is a case reported in which the former was associated with a pituitary tumor. A knowledge of these aneurysmal types and vascular anomalies is essential for the pituitary surgeon. Magnetic resonance imaging is now the radiological procedure of choice in the preoperative assessment of patients suspected of having pituitary tumors or recurrences, because, in addition to depicting the tumor, it defines the arterial anatomy and excludes all but very small coexistent aneurysms.