Can Extra Adrenal Cortisol Secretion Occur in an Adrenalectomized Patient?

Abstract

Abstract Background: Established medical practice is that adrenalectomized patients require lifelong steroid replacement. We report a case which challenges that assumption. Clinical Case: A 38 year old female underwent transsphenoidal resection of a proven ACTH secreting pituitary adenoma. Post operatively her pituitary function was preserved, but due to residual tumour activity and the desire to preserve fertility, she had a bilateral adrenalectomy one year later and commenced hydrocortisone replacement. Subsequent pituitary imaging did not show recurrence of the tumour and her visual fields were stable, however her ACTH remained elevated at 100 and 130ng/L (09:00 <50 ng/L) despite steroid replacement.14 years after adrenalectomy she noticed weight gain and increased body hair. She also reported sometimes missing her hydrocortisone due to her busy job without ill effects. Her 9 am cortisol pre-hydrocortisone was elevated at 333 nmol/L (9am: 140–690 nmol/L) with ACTH of 203.0 ng/L (09:00 <50ng/L) She was able to suppress cortisol normally after a Dexamethasone suppression test. CT of her adrenals found no adrenal tissue. By now she had weaned herself off hydrocortisone, keeping an emergency supply. SST showed a cortisol of 320 nmol/L at 30 minutes, 360 nmol/L at 60 minutes with an elevated ACTH of 140 ng/L (09:00 <50 ng/L). Her weight gain and body hair growth stabilised. Discussion: We have demonstrated that this adrenalectomized patient has ACTH driven endogenous cortisol secretion which may be due to residual adrenal tissue due to seeding after surgery or the presence of steroid synthesis elsewhere. Extra adrenal sources for glucocorticoid production are known such as skin, gonads and thymus. However, the levels are insufficient to mount a significant stress response. There is evidence of adrenal regeneration in adrenalectomized animals. The regeneration is primarily of the adrenal cortex and does not involve the medulla. There has been one case report in literature of a 11 year old German boy who had adrenal regeneration detected on adrenal scintigraphy (Bilateral normal adrenal glands with normal activity) 13 years after adrenalectomy for Cushing’s disease.