Introduction: Ectopic ACTH syndrome (EAS) is associated with small cell carcinoma of the lung. It is reported as a rare condition. Here we report three cases of undiagnosed bronchogenic carcinoma who presented with EAS within a period of 12 months.
67-year-old lady, smoker, presented with severe proximal myopathy of 4 week duration. Clinically she appeared cushingoid. Newly diagnosed Type two diabetes. Lab tests potassium 2.3 mmol/l, bicarbonate 37 mmol/l. CXR showed abnormal shadow at left hilum. 0900 h cortisol 1406, ACTH 80 (normal 040). CT scan of thorax/abdomen/pelvis revealed large left hilar mass, infiltrating left main bronchus, multiple hepatic and bilateral adrenal metastatic lesion.
A 53-year-old female smoker presented with shortness of breath and weight loss. Her blood pressure had become uncontrolled despite being on several antihypertensives. Newly diagnosed diabetes.She was cushingoid and had severe proximal myopathy. Lab test potassium was 2.5 mmol/l, bicarbonate 35 mmol/l. Glucose 30 mmol/l. Chest radiograph right lower lobe consolidation. An early morning cortisol >1600l/l (normal range 450700 nmol/l). ACTH 96 ng/l (normal range <80 ng/l) in presence of high cortisol. Bronchoscopy-bronchogenic carcinoma. Histology small cell lung carcinoma (SCLC).
A 70-year-old male, non-smoker presented with shortness of breath for 6 months. He had dysphagia, weight loss and hoarseness of voice. Lab tests potassium of 2.5 mmol/l, with normal sodium, urea, creatinine. Bicarbonate 35 mmol/l. Chest radiograph left hilar mass, left basal consolidation. 0900 h cortisol sample 1595 nmol/l (normal 450700 nmol/l).
CT staging-multiple masses within the mediastinum and left hilum. There were multiple liver metastasis. Bronchoscopy-tumours in the left upper lobe. Histology-small cell lung carcinoma.
Discussion: EAS is reported as a rare diagnosis in SCLC (5% of all cases). Here we report three cases who presented with EAS in previously undiagnosed bronchogenic carcinoma. The clue to diagnosis was unexplained hypokalaemia and alkalosis in all cases which was confirmed by biochemical testing. Early recognition of the condition allows symptom control to improve quality of life but does not affect prognosis.