A Rare Case of Syndrome of Inappropriate Anti-diuretic Hormone in Non-small Cell Lung Cancer Presenting as Superior Vena Cava Syndrome.

Syndrome of inappropriate anti-diuretic hormone (SIADH) secretion is uncommon in small cell lung cancer (SCLC), but even more rare in cases of non-small cell lung cancer (NSCLC). We report a case of a 59-year-old male who presented with superior vena cava (SVC) syndrome. After further investigation, he was diagnosed with adenocarcinoma of the lung. He delayed his medical care and his condition worsened. He was diagnosed with SIADH as an incidental finding on routine lab draw. Radiotherapy was subsequently initiated, and after one week of treatment, the patient showed marked clinical improvement. In this article, we also review the current indications for radiotherapy in various lung cancers and the management of SIADH.