2381/45398 Gaurav Singh Gulsin Gaurav Singh Gulsin Madeleine Louisa Bryson Jacobs Madeleine Louisa Bryson Jacobs Shailesh Gohil Shailesh Gohil Adam Thomas Adam Thomas Miles Levy Miles Levy Competing interests in a lung cancer with metastasis to the pituitary gland: syndrome of inappropriate ADH secretion versus diabetes insipidus. University of Leicester 2019 neuroimaging magnetic resonance imaging computed tomography vasopressins conflict of interest cancer diabetes insipidus hypopituitarism inappropriate adh syndrome neoplasm metastasis breast diagnosis pituitary gland sodium lung cancer metastasis to the lung pituitary adenoma water balance secondary malignant neoplasm of pituitary gland lung cancer stage iv 2019-08-29 14:32:41 Journal contribution https://figshare.le.ac.uk/articles/journal_contribution/Competing_interests_in_a_lung_cancer_with_metastasis_to_the_pituitary_gland_syndrome_of_inappropriate_ADH_secretion_versus_diabetes_insipidus_/10210202 Metastases to the pituitary gland are rare; cancers that most commonly metastasize to the pituitary are breast and lung cancers. No specific computed tomography or magnetic resonance imaging features reliably distinguish primary pituitary masses from metastases. A combination of a detailed clinical assessment together with specialist endocrine and neuroradiology support is essential to make the rare diagnosis of a pituitary metastasis. We present the case of a man with metastatic lung cancer, initially presenting as hypopituitarism. Subtle features in the history, together with neuroimaging findings atypical for pituitary adenomas, provided clues that the diagnosis was one of the pituitary metastases. Treatment of diabetes insipidus (DI) with replacement antidiuretic hormone (ADH) was complicated by extreme difficulties in achieving a satisfactory sodium and water balance. This was the result of coexistent DI and syndrome of inappropriate ADH secretion perpetuated by the patient's primary lung cancer, a phenomenon not previously described in the literature.