Squamous Cell Carcinoma of the Larynx with Syndrome of Inappropriate Secretion of Antidiuretic Hormone

Background: Paraneoplastic syndromes result from the secretion of hormones by a tumor giving rise to different syndromes. Lung carcinomas are the most common tumors causing paraneoplastic syndromes. The most common is the syndrome of inappropriate secretion of arginine vasopressin (SIADH).
Objective: To describe the case of a patient with larynx cancer and secondary SIADH and review of the literature.
Case Report: We present the case of an 80-year-old man with dry cough, dysphonia and severe hyponatremia. Physical examination was unremarkable. After admission he developed acute stridor and a tracheostomy was performed. Serum and urine analysis confirmed the presence of SIADH in the absence of renal, adrenal of thyroid dysfunction. No SIAHD producing drugs were reported. An ORL examination revealed the presence of a thickened area just below the right vocal cord. Hystopathological examination was suggestive of squamous cell carcinoma. After total laryngotomy, the final hystopathological exam reported the presence of a well differentiated squamous cell carcinoma. Hyponatremia was corrected with restriction of water intake to a maximum of 500 cc daily. Concomitant radiotherapy was administered.
Conclusion: Ectopic or inappropriate hormone secretion is uncommon in patients with the head and neck cancer. However, this condition should be included in the differential diagnosis of SIADH.