Diverse cases of ectopic Cushing’s syndrome
JERRY GREENFIELD, EDITOR-IN-CHIEF, ENDOCRINOLOGY, DIABETES & METABOLISM CASE REPORTS | Hot topics
For this anniversary issue, we invited the Editors-in-Chief of the Society's journals to write about a topic of their choice.
Cushing’s syndrome from ectopic adrenocorticotrophin (ACTH) secretion is a rare clinical occurrence. Its diagnosis is often delayed due to its non-specific presentation. A number of case reports of ectopic ACTH secretion in Endocrinology, Diabetes & Metabolism Case Reports have been particularly instructive.
Faisal and Debono report a case of a 65-year-old man who presented during the COVID-19 pandemic with unintentional weight loss (atypical in Cushing’s disease), new-onset type 2 diabetes and resistant hypertension. The presence of Cushingoid features and typical biochemical abnormalities (hypokalaemia and neutrophilia) led to the rapid diagnosis of Cushing’s syndrome by endocrine testing. He was diagnosed with an ACTH-secreting metastatic small cell lung cancer and treated with metyrapone.
In addition, Chunharojrith et al. report a case of ectopic ACTH secretion from a primary renal neuroendocrine tumour treated with pasireotide and surgery. Finally, Lawrence et al. describe a case of ectopic ACTH secretion from a thymic neuroendocrine carcinoma, controlled by ketoconazole and mifepristone prior to mediastinal surgery.
These cases serve to highlight the masquerading presentation of Cushing’s syndrome due to ectopic ACTH secretion, and provide a reminder that the constellation of typical clinical features (diabetes, resistant hypertension, proximal myopathy) with hypokalaemia, neutrophilia and metabolic alkalosis should raise clinical suspicion of this possibility. Rapid control of hypercortisolism with medical therapy, followed by definitive treatment of the culprit tumour, offers the patient the best chance of survival.