SUN-408 Pituitary Metastasis: Central Diabetes Insipidus Unmasked by Corticosteroids: Case Series and Review of Literature

Background Metastasis to the pituitary gland is rare encounter and is more common amongst the elderly population with advanced malignancy. An estimated 1% of all pituitary tumour resections are metastatic. Primary sites that frequently metastasize include breast and lung carcinomas. In the recent decade, advancement in the field of oncology with multiple modalities of therapy has led to prolonged survival of patients with advanced stages of malignancy.Herein, we present three cases and review of literature of pituitary metastasis presenting as central diabetes insipidus incidentally unmasked following administration of corticosteroids. Objective To establish the common clinical features, establish variations in clinical presentations and natural progression of disease in patients with pituitary metastasis. Methods Three cases of central diabetes insipidus unmasked by corticostetoroids in pituitary metastasis were presented. A total of 9 other cases with central diabetes insipidus as first clinical manifestation unmasked by corticosteroid published from 2007-2018 were reviewed. Pertinent references were searched using windows remote search model on PubMed. Non-English articles were excluded. Results A compilation of 9 previously reported cases of central DI unmasked by corticosteroids from 2007 to 2017 along with the present 3 cases were performed (Table 1). There was equal gender prevalence with a mean age of 61 (range 56-80 years old). More than 75% of the cases described here had previously been diagnosed with advanced malignancies of varying primary sites. The remaining 25% presented with varying symptoms of hypopituitarism as the harbinger to the discovery of the primary neoplasm. Amongst the literature review and cases presented, primary malignancies with pituitary metastasis included lung adenocarcinoma (33%), breast carcinoma (25%), nasopharyngeal carcinoma (16%), renal cell carcinoma (8%), hepatocellular carcinoma (8%) and gastric adenocarcinoma (8%). It is noteworthy that two of three present cases identified, were the result of directly infiltration of nasopharyngeal carcinoma to the pituitary gland. There is limited data documenting the prevalence of nasopharyngeal carcinoma with pituitary metastasis within the Asian population. Conclusion Central diabetes insipidus unmasked by corticosteroids is a less recognized, potentially lethal but fully reversible complication of pituitary metastasis. Symptoms or signs of central diabetes insipidus should be sought in all patient with advanced malignancies presenting with polyuria and hypernatremia. Prompt restoration of pituitary hormones is warranted in affected patients to allow timely restoration of hormonal balance and preventing endocrine emergencies.