Cushing Syndrome: Secondary to Squamous Cell Carcinoma of the Lung

Cushing syndrome secondary to ectopic Adrenocorticotrophic (ACTH) hormone secretion is an uncommon entity mostly caused by small cell lung cancer or bronchial carcinoids. It can be characterised by absence of classical cushingoid features. Ectopic ACTH syndrome is characterised by severe and progressive hypercortisolemia. Thus, prompt identification and treatment can significantly decrease morbidity in affected patients. A 57-year-old male patient with a history of Stage 4 squamous cell cancer of the lung presented with worsening hyperglycemia and hypokalemia. Physical exam was notable for facial plethora and hypertension. Hormonal testing showed a very high serum cortisol, ACTH and 24 hours urinary free cortisol levels. MRI of the brain was normal. A diagnosis of ectopic ACTH syndrome was confirmed. The patient was started on Ketoconazole and his cortisol levels improved. The patient was discharged and eventually was lost to follow up.