Syndrome of inappropriate antidiuretic hormone in a patient with leptomeningeal carcinomatosis

Leptomeningeal carcinomatosis is a condition in which metastatic cancer cells infiltrate the meninges of the brain and spinal cord, progressing to also involve the cerebrospinal fluid. Incidence of leptomeningeal carcinomatosis arising from an esophageal cancer is particularly rare. Here, we present a case report of a 76-year-old Caucasian man with a history of esophageal adenocarcinoma status-post chemoradiation followed by resection. He was admitted to our unit for intractable headache, nausea without emesis, anorexia, weakness, gait instability, delirium, syncope, and near syncope. Our diagnostic workup revealed leptomeningeal carcinomatosis and syndrome of inappropriate antidiuretic hormone. Our patient was treated with lumbar puncture for the headache, methotrexate for the leptomeningeal carcinomatosis, and table salt for the syndrome of inappropriate antidiuretic hormone. Despite our best efforts, our patient died 6 weeks posttreatment. Understanding the molecular pathogenesis of the development of syndrome of inappropriate antidiuretic hormone associated with leptomeningeal carcinomatosis from metastatic esophageal adenocarcinoma would help us to identify patients at risk and treat them accordingly.