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BMJ Case Reports 2017; doi:10.1136/bcr-2017-219921
  • Rare disease
  • CASE REPORT

An unusual case of Cushing's syndrome due to bihormonal ACTH–prolactin secreting pituitary macroadenoma with rapid response to cabergoline

  1. Rinki Murphy1
  1. 1Department of Endocrinology, Auckland District Health Board, Auckland, New Zealand
  2. 2Department of Endocrinology, Waitemata District Health Board, Takapuna, New Zealand
  1. Correspondence to Dr Shalini Kunasegaran, shal84{at}gmail.com
  • Accepted 13 July 2017
  • Published 7 August 2017

Summary

A 23-year-old man presenting with florid Cushing's syndrome was found to have high plasma ACTH and very high serum prolactin. Pituitary MRI showed a large invasive macroadenoma. Low-dose cabergoline promptly suppressed both ACTH and prolactin levels within 2 weeks, with unexpected clinical and biochemical hypocortisolism requiring hydrocortisone replacement. Secondary hypogonadism was reversed. Clinical and biochemical remission of his Cushing's syndrome together with significant shrinkage of his macroadenoma has been maintained for 1 year on cabergoline 0.5 mg twice weekly. Reduction in pituitary tumour volume and brisk fall in serum prolactin in response to low-dose cabergoline is regularly observed in patients with macroprolactinomas, but the concurrent fall in the plasma ACTH level and hypocortisolism was a pleasant surprise. We assume that he most likely has a single bihormonal adenoma that is enriched with dopamine-2 receptors.

Footnotes

  • Contributors SK has produced the report and literature review. RM and MSC were involved in the patients' clinical care and contributed to the writing. IH provided guidance and contributed to the writing.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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