Uncommon presentation of small cell lung carcinoma with ectopic adrenocorticotropic hormone secretion and resistant hypokalemia: A case report

Abstract

Paraneoplastic syndromes can serve as initial indicators of malignancy, with small cell lung cancer accounting for 13% of new lung cancer diagnoses. The most prevalent paraneoplastic syndrome associated with small cell lung cancer is inappropriate antidiuretic hormone syndrome, followed by ectopic adrenocorticotropic hormone-mediated Cushing’s syndrome. Cushing’s syndrome manifests as hypercortisolemia and presents with diverse symptoms, including central obesity, plethora, menstrual irregularities, hypertension/diabetes mellitus, ecchymoses, osteoporosis, muscle weakness, virilization/hirsutism, skin atrophy, decreased libido, and infertility. This case report details the uncommon presentation of small cell lung carcinoma manifesting with ectopic adrenocorticotropic hormone secretion (EAS), leading to resistant hypokalemia and rhabdomyolysis. This case emphasizes the importance of considering EAS in severe cases of Cushing's syndrome and highlights the diagnostic and therapeutic challenges associated with this condition.

Keywords

• Small cell lung cancer
• Cushing’s syndrome
• Hypokalemia