Hypopituitarism caused by intrasellar aneurysms.

OBJECTIVE: To determine the prevalence, clinical presentation, and outcome of hypopituitarism due to an intrasellar aneurysm.

PATIENTS AND METHODS: We performed a retrospective review of Mayo Clinic, Rochester, Minn, medical records from 1950 through 1995. We calculated the prevalence of hypopituitarism, characterized the clinical presentation, and evaluated postoperative outcomes.

RESULTS: Of 4087 patients with a diagnosis of hypopituitarism, 7 had hypopituitarism due to an intrasellar aneurysm, accounting for a prevalence of 0.17%. Adrenal, thyroid, and gonadal deficiencies were observed in 7, 6, and 5 patients, respectively. The prolactin level was increased in the 2 patients in whom it was measured. No patient had diabetes insipidus. All had visual impairment. In 5 patients an intrasellar aneurysm of the internal carotid artery was diagnosed preoperatively based on 1 or more imaging procedures. In the other 2 patients (1 with an internal carotid artery aneurysm and 1 with an anterior cerebral artery aneurysm), the diagnosis was made at surgical exploration. Four patients underwent a surgical procedure: 2 had direct packing of the aneurysm, and 2 had a bypass with proximal carotid occlusion or aneurysm trapping. Pituitary function remained unchanged postoperatively.

CONCLUSION: An intrasellar aneurysm is a rare cause of hypopituitarism (0.17% of cases). Preoperative diagnosis is essential for successful surgical outcomes. Hypopituitarism is usually permanent.