MON-431 Clinical Presentation of Metastases to the Pituitary: A Swedish Nationwide Study

Pituitary metastases (PM) are often considered to be associated with advanced stages of neoplastic disease, and diabetes insipidus the dominating endocrine consequence. With recent advancements in cancer therapy many patients survive relapses, and life expectancy has improved. In addition, enhanced follow-up programs including more sensitive radiological techniques facilitate earlier detection of metastases. Purpose: To investigate the current clinical presentation of PM, in particular hormonal disturbances, MRI tumor characteristics, and temporal relation to the primary tumor. Patients: Thirty-eight patients diagnosed with PM between 1996 and April 2018 at the University hospitals, Sweden. Methods: PM was confirmed by histopathological examination in 27 patients. In 11 patients the diagnosis of PM was based on radiological findings, including rapid progression of a pituitary lesion in patients with disseminated cancer. Medical charts served to identify presenting symptoms and signs, hormonal and ophthalmological status, treatment, and survival. MRI/CT of the sellar region were re-examined centrally. Results: Breast and lung cancer were the most common primary sources, found in 17 and 8 patients. In 9 patients (6 breast cancers), PM was the only detected metastasis. Nine of 17 PM from breast cancers appeared ≥10 years after diagnosis of the primary tumor. PM preceded the diagnosis of the primary tumor with 1 year in 3 patients. Twenty-five of 37 (68%) patients had TSH deficiency, 26/35 (74%) had ACTH deficiency. At presentation 10/17 with early morning cortisol ≤100 nmol/L vs. 3/13 with cortisol ≥200 nmol/L complained of fatigue, nausea/vomiting, loss of appetite, weight loss, myalgia/arthralgia. Ten of 38 patients had diabetes insipidus. Sixteen patients had visual field defects, 8 had diplopia. Intra/suprasellar extensions were the most frequent on imaging. Pituitary adenoma was initially considered as the only likely etiology in 7 patients. Conclusion: PM may be mistaken for a pituitary adenoma, present as the only metastasis, and appear late in time, especially in breast cancer. Hypocortisolism, the most common endocrine consequence of PM, may mask as cancer-related malaise. An increased awareness of PM and undiagnosed anterior pituitary failure, especially adrenal insufficiency, should improve management and quality of life of patients with malignancies.