Endocrine Abstracts

Introduction: Cushing’s syndrome is characterised by glucocorticoid excess. This is more commonly caused by excess adrenocorticotropic hormone (ACTH) produced either by a pituitary tumour (Cushing’s disease) or ectopic secretion. An example of the latter is the production of ACTH by a lung carcinoma (typically small cell)¹. Other causes of Cushing’s syndrome include long term steroids or adrenal carcinoma.

Case history: A 62-year-old lady was admitted with a history of breathlessness. On examination she had signs of Cushing’s syndrome including pigmented skin, proximal myopathy and easy skin bruising. She was noted to have lost some weight. Twenty-four hour urine collection for cortisol was 1942 and 2252 nmol on 2 consecutive days. She failed overnight, low and high dose dexamethasone supression tests. She had raised ACTH levels, 24 h urinary 5HIAA and 24 h urinary cortisol following a high dose dexamethasone suppression test, all of which suggested ectopic ACTH secretion rather than adrenal disease. An abdominal CT scan showed bilateral adrenal nodular enhancement. CT scan of thorax showed a 2 cm ill defined nodule in the posterior segment of the left upper lobe of the lung. CT biopsy of her adrenal masses showed adenoma with no evidence of malignancy. CT biopsy of the lung nodule revealed small cell lung carcinoma. She was referred to Oncology for chemotherapy for her lung carcinoma and endocrine review, she was commenced on Metyropone 250 mg three times daily for treatment of Cushing’s syndrome.

Discussion: This lady presented with weight loss rather than weight gain along with signs of Cushing’s syndrome which highlights the possibility of ectopic ACTH secretion, ultimately found to be secreted by lung carcinoma, which was classically small cell.

Reference: 1. Paraneoplastic syndromes. West J Med 1980 March 132 (3) 189–208.