Cushing’s syndrome (CS) resulting from excess production of endogenous cortisol is rare, with an estimated incidence of 2-8 people per million annually.(1) Of endogenous CS, adrenal cortisol production independent of corticotrophin is the underlying aetiology in approximately 20-30%.(1)
Many features of CS are non-specific including weight gain, hypertension, hyperlipidaemia and insulin resistance or diabetes mellitus, whilst more specific features include facial plethora, easy bruising, and violaceous striae.(2)
A 36-year-old woman, 18-months post-partum, presented with secondary amenorrhoea 6-months post cessation of breast feeding, lethargy, sleep disturbance, easy bruising, facial plethora and abdominal striae. She additionally presented with carotenaemia, with yellowing of her hands and feet. Her diet was not suggestive of carotene excess.
Biochemical testing confirmed CS, in addition to hypercholesterolaemia with a LDL of 4.8nmol/L and an elevated serum carotene of 21.2umol/L (1.0-5.5umol/L). A CT adrenal study revealed a right-sided adrenal lesion measuring 30 x 23 x 41mm with +12.72 HU.
Histology following laparoscopic right adrenalectomy confirmed an adrenal cortical adenoma measuring 35mm. Hydrocortisone therapy was commenced and weaned to 10mg twice daily. Lipid profile is improving without lipid-lowering therapy, with a LDL of 3.2 nmol/L, and reducing carotene level of 16.5umol/L. Regular menses returned 2 months post-operatively. There has been a significant improvement in the clinical features and symptoms of CS, as well as improvement in skin yellowing.
Excessive ingestion of foods high in beta-carotene is the primary cause of carotenaemia, and less commonly due to an underlying disease such as diabetes mellitus, hypothyroidism and nephrotic syndrome.(3) A mechanism of carotenaemia common to such conditions is reported to be related to the elevation in serum lipids.(3)
At the time of writing, there is no other known case report of carotenaemia associated with Cushing’s disease or syndrome. Underlying dyslipidaemia associated with CS is a plausible correlation.