Endocrine Abstracts

A 66-year-old man was referred in May 2004 with history of rapid onset of diabetes, severe back pain with vertebral collapse and hypokalaemia (K+2.9 mmol/l). GP suspected Cushing’s syndrome. Random cortisol was 905 nmol/l and 24 h urinary free cortisol 1741 nmol/24 h.

He was admitted for investigations which were highly suggestive of ectopic ACTH secretion with cortisol levels failing to suppress after low- and high-dose dexamethasone and ACTH levels high at 270 ng/l and no cortisol response to a CRF test.

CT scan of lungs showed a possible endobronchial lesion but bronchoscopy was normal. Subsequent CT lung in Feb 2005 showed a 14 mm well defined ovoid shaped soft tissue nodule in L lower lobe. CT and MRI showed L adrenal enlargement but no discreet mass. MRI pituitary was normal.

Clinically he was judged too unwell for surgical intervention or petrosal catheter and was started on metyrapone. A metyrapone day curve showed marked improvement with a mean cortisol level of 383 nmol/l and he improved slowly during a prolonged admission.

At clinic follow up 10 weeks after discharge his diabetes was well-controlled but although he had initially felt better he had felt less well for 2 weeks with anorexia and nausea. Random cortisol was 63 nmol/l. Over the next 2 months metyrapone was adjusted downwards with repeated day curves and in December mean cortisol was 94 nmol/l on low dose metyrapone and this was stopped. In January mean day curve cortisol off metyrapone was 98 nmo/l with symptoms of hypoadrenalism and he was started on a small dose of Hydrocortisone. Subsequently he continues to be well with no evidence of recurrent Cushing’s but cortisol low enough to need ongoing hydrocortisone replacement.

His bronchial lesion has been reviewed with repeated scans by lung cancer MDT who report insufficient suspicion of tumour to recommend surgery.

Conclusion: This patient had severe Cushing’s syndrome with features of ectopic ACTH secretion which appears to have progressed spontaneously to hypoadrenalism. Is this cyclical Cushing’s? Is there any indication to excise the bronchial lesion?