To Örebro University

Objective: To investigate the contemporary presentation of pituitary metastases.

Patients: Thirty-eight patients diagnosed with pituitary metastases from 1996 to 2018 in Sweden.

Methods: Pituitary metastases were confirmed by histopathology (n 5 27) or considered highlylikely according to radiological findings, including rapid tumor progression (n 5 11). Medicalrecords were reviewed and sellar images reexamined centrally.

Results: Breast and lung cancers were the most common primary tumors, in 45% and 21% ofpatients, respectively. Sixty-seven percent of breast cancers overexpressed human epidermalgrowth factor receptor 2 (HER2); 53% of pituitary metastases from breast cancers appeared $10years after diagnosis of the primary tumor. At presentation, 71% appeared to have ACTH de-ficiency, 65% had TSH deficiency, and 26% had diabetes insipidus. Fatigue, nausea/vomiting, lossof appetite, weight loss, myalgia, and/or arthralgia were reported in 47% of patients withmorning cortisol ,100 nmol/L vs 23% with cortisol $200 nmol/L. Sixteen patients had visual fielddefects, and eight had diplopia. Intrasellar and suprasellar tumor growth was the most frequentfinding. Initially, a pituitary adenoma was considered the etiology in 18% of patients.Radiotherapy, pituitary surgery, and chemotherapy were used in 68%, 68%, and 11% ofpatients, respectively. One and 2 years after diagnosis of pituitary metastases, 50% and 26% ofpatients were alive.

Conclusion: Pituitary metastases may be mistaken for pituitary adenomas and can appear late,especially in breast cancer. Breast cancers overexpressing HER2 seem prone to metastasize tothe pituitary. Hypocortisolism may be misdiagnosed as cancer-related malaise. An increasedawareness of pituitary metastases and undiagnosed pituitary failure can improve management inthese patients.