Syndrome of inappropriate antidiuretic hormone secretion (SIADH) results in impairment of water excretion and excessive free water reabsorption in the collecting ducts due to increased antidiuretic hormone secretion relative to serum osmolality. This condition is associated with various malignancies. A 44-year-old female was admitted to our hospital with the complaints of general weakness, nausea, vomiting, poor intake, and lethargy. Initial laboratory results revealed a Na of 102 mmol/L with normal renal function. Further work up for SIADH confirmed the diagnosis. The patient was treated with hypertonic saline with appropriate rate in HCU and she improved symptomatically. Then we recognized the patient has difficulties swallowing solid food, decreased appetite for the last 3 months, and weight loss of around 7 kg in the last 5 months. Upper endoscopy was performed, revealing the presence of an ulcerative and proliferative growth in the mid-esophagus. Histopathology of the growth revealed a well differentiated, papillary type adenocarcinoma. This case demonstrates that esophageal adenocarcinoma could induce SIADH as a paraneoplastic syndrome.

Keywords: Carcinoma of esophagus, Paraneoplastic syndrome, Syndrome of inappropriate antidiuretic hormone secret, SIADH