Endocrine Abstracts

Introduction: Adrenal incidentaloma prevalence is rising with the advancement of imaging techniques. The hormonal work-up should always include free metanephrines for the diagnosis of a pheochromocytoma and 1 mg overnight dexamethasone suppression test for the diagnosis of autonomous cortisol secretion. These tumors have two distinct embryologic origin and don’t usually coexist, and when they do, it occurs in case of an ectopic adrenocorticotropic hormone (ACTH) production by the pheochromocytoma. We herein describe a pheochromocytoma with an ACTH-independent possible autonomous secretion of cortisol.

Observation: We report the case of a 57 years old woman, with a history of an insulin-treated type 2 diabetes mellitus, high blood pressure treated with captopril and amlodipine, atrial fibrillation treated with beta-blockers and vitamin K antagonists, referred to our department for an adrenal incidentaloma. It was a left adrenal mass measuring 28*23*32 mm with a spontaneous density of 28HU, an absolute washout of 71% and relative washout of 40%. She didn’t have any clinical sign of pheochromocytoma or Cushing syndrome. On laboratory investigation, she had a glycated hemoglobin of 8,7%, a low potassium level at 3.4 mmol/l and TSH levels at 1.38 μUI/ml. Adrenal hormonal work-up found urinary fractionated metanephrines levels at 364 nmol/creatinine (3*normal) and urinary fractionated normetanephrines levels at 463 nmol/creatinine (1.65*normal) confirming the diagnosis of pheochromocytoma. Cortisol levels after 1 mg overnight dexamethasone suppression test were at 87 nmol/l, confirming a possible autonomous secretion of cortisol with ACTH levels inferior to 5 pg/ml excluding an ectopic secretion of ACTH. Aldosterone and renin levels were assessed and a secondary hyperaldosteronism was discovered with aldosterone levels at 740 pmol/l, renin levels at 53 pg/ml and aldosterone/renin ratio at eight. Sex hormones and steroid precursors were normal. The diagnosis of a corticomedullary mixed tumor of the adrenal gland is suspected in our patient. Complementary work up didn’t find osteoporosis, calcitonin and calcium levels were normal, transthoracic echocardiography concluded to a concentric hypertrophy of the left ventricule. The patient was put under alpha blockers and was referred to surgery.

Conclusion: This case illustrates the presentation of a corticomedullary mixed tumor, which is a rare adrenal tumor presenting as a pheochromocytoma with an ACTH-independent cortisol production. The pre and peri operative management includes the management of a pheochromocytoma and an autonomous cortisol secretion. Confirmation of this diagnosis relies on histology and immunohistochemistry.