O-04 A diagnostic riddle of an adrenal incidentaloma

Abstract

Abstract Clinical case A 78-year-old male underwent preoperative CT as transcatheter aortic valve implantation was planned. In addition to a 6 cm incidental mass in the right adrenal, it also revealed unspecific pulmonary nodules. The patient was referred to the Endocrine unit. Non-contrast adrenal CT demonstrated a heterogenous 6 cm tumor, < 10 HU. The patient had a history of psoriasis, type 2 diabetes mellitus, hypertension, chronic kidney disease, atrial fibrillation, peripheral artery disease, aortic stenosis and coronary artery disease. Clinical examination revealed no signs of Cushing's syndrome. First, normal blood metanephrine/normetanephrine concentrations confirmed that pheochromocytoma was ruled out. The possibility of a metastatic tumor mass was investigated by tumor biopsy, histopathology was compatible with an adrenocortical neoplasm, Ki67 2%. Further laboratory work-up is given in Table 1. How should the laboratory findings be interpreted? Primary aldosteronism was ruled out. Cortisol was not suppressed on 1mg DST, in contrast to perfectly normal 24h urinary free cortisol. Late night salivary cortisol (LNSC) was markedly increased, 1210 nmol/l and low ACTH concentration further suggested true hypercortisolism. Does the patient suffer from hypercortisolism? The patient had no clinical signs of Cushing syndrome, albeit cardiometabolic diseases. False positive DST and LNSC results were suspected. Indeed, the patient was using 1% hydrocortisone lip lotion. On repeat screening after discontinuation of hydrocortisone, LNSC was 3.8 nmol/l, and DST remained positive (258nmol). The patient was diagnosed with autonomous cortisol excess (MACS) (1). Should the patient undergo surgery for the right adrenal mass? MACS in combination with relevant co-morbidities and large tumor size indicated surgery (1), which the patient consented to. After surgery, cortisol concentrations remained suppressed which prompted hydrocortisone replacement therapy. Final pathology review classified the tumor as an adenoma, Weiss Score 0/9 and Ki-67 2%. Conclusion False positive cortisol screening tests are common and must be ruled out before surgery. For DST, common explanations are exogenous glucocorticoid use, drugs that accelerate dexamethasone metabolism and estrogen induced increase in CBG. The most common pitfalls for LNSC are deranged circadian rhythm and exogenous hydrocortisone. Reference (1). Fassnacht el al. European Society of Endocrinology clinical practice guidelines on the management of adrenal incidentalomas. European Journal of Endocrinology,2023; 189(1): G1–G42.Table 1