Premises: Ectopic adrenocorticotropic hormone (ACTH) production has been reported with more frequency in recent years due to increased awareness of neuroendocrine neoplasms. Ectopic ACTH syndrome (EAS) also represents 15% of cases of small cell lung cancer.Description of the Case report: An Italian 78 year-old male, with history of arterial hypertention, diabetes and hypothyroidism, presented to the Emergency Department with generalized weakness and peripheral edema. He presented Cushing facies. The initial blood tests showed anemia (Hb 9.5g/dL) and hypokalemia (1.7mmol/L), BNP 298 pg/ml. Thoracic CT scan showed bilateral pleural effusion and emphysema. The severe hypokalemia didn’ t respond to treatments. so we dosed cortisolemia (62 ug/dl), ACTH (338 pg/ml) and cortisoluria (239.2 ug/ml). The LIDDLE-2 test with dexamethasone suggested for ectopic origin of Cushing syndrome. Digestive endoscopy with biopsy and abdominal US were negative. Bronchoscopy with EBUS and biopsy were made. The liquid-based cytology suspected neuroendocrin cancer. The istological diagnosis was small cell lung cancer. General conditions quickly got worse, the patient developed severe respiratory failure and a new lung TC scan showed Lymphangitis carcinomatosa. The patient died.Conclusions: Ectopic ACTH syndrome should always be considered in differential diagnosis with Cushing syndrome. The dignosis is rarely easy for clinicians. True diagnosis and then correct therapy can save the patient’s life.
A 2025 study studied this question.