Bilateral
adrenalectomy (BLA) is a treatment option for patients with
Cushing's Disease (CD) if transsphenoidal pituitary surgery fails or is not a therapeutic option. For most patients, BLA eliminates endogenous
glucocorticoid and
mineralocorticoid production, but for a small number of patients, endogenous secretion of adrenal
hormones from adrenal tissue continues or recurs, leading to signs and symptoms of
hypercortisolism. If adrenal tissue is confined to the adrenal bed, it is considered adrenal remnant tissue, while if it is outside the adrenal bed, it is considered adrenal rest tissue. We retrospectively evaluated morning serum
cortisol, nighttime serum
cortisol, nighttime salivary
cortisol, and 24-h urine free
cortisol on at least three occasions in 10 patients suspected of having endogenous
cortisol production. Imaging of adrenal remnant tissue was also reviewed. Ten of 51 patients who underwent BLA during this time period had adrenal remnant/rest tissue marked by detectable endogenous
glucocorticoid production; 9 of the 10 patients had signs and symptoms of
hypercortisolism. Localization and treatment proved difficult. We conclude that the incidence of adrenal remnant/rest tissue in those undergoing BLA following unsuccessful pituitary surgery was 12% although there may have been a selection bias affecting this prevalence. The first indication of remnant tissue occurrence is a reduction in
glucocorticoid replacement with symptoms of
hypercortisolism. If this occurs, endogenous
cortisol production should be tested for by
cortisol measurements using a highly specific
cortisol assay while the patient is taking
dexamethasone or no
glucocorticoid replacement. Endocrinologists need to monitor the development of both adrenal remnant tissue and Nelson's syndrome following BLA.