AVP and neoplasm: Although an ectopic and inappropriate production of antidiuretic hormone (ADH) is uncommon in RCC compared with other tumor types, it may partially explain the occurrence of hyponatremia, as well as a postnephrectomy renal dysfunction.17,20 In addition, hyponatremia can occur as a consequence of gastrointestinal, neurological, or endocrinological adverse events during ICI treatment.