Endocrine Abstracts

Introduction: Chronic catecholamine overproduction in pheochromocytoma may lead to a proinflammatory and hypermetabolic state characterized by increased resting energy expenditure and brown adipose tissue activation. Non-neoplastic hypercortisolaemia aka pseudo-Cushing syndrome (PCS) is a physiological overactivation of the hypothalamic–pituitary–adrenal axis by e.g. depression, eating disorders, extreme exercise, obesity, alcoholism, poorly controlled diabetes and cachexia. Here we describe an unusual case of pheochromocytoma-induced PCS.

Case report: A 66-year-old woman was referred to the hospital due to pronounced weakness, loss of appetite, apathy and weight loss of 5 kg within a month, a newly diagnosed diabetes mellitus and poorly controlled hypertension. Because of a rapid weight loss and suspicion of malignancy a chest and abdominal CT was performed, showing a heterogeneous, well-demarcated litho-cystic lesion (measuring 32×25 mm) in the right adrenal gland, with inhomogeneous contrast enhancement. Metanephines’ levels in serum were markedly elevated, as well as ACTH (535 pg/ml), highly increased 24 h urinary free cortisol excretion, high plasma DHEAS and testosterone. The initial differential diagnosis was as follows: a coexistence of pheochromocytoma or an ACTH-dependent hypercortisolemia or ectopic ACTH production by pheochromocytoma. An MRI ruled out pituitary tumors and a Ga⁶⁸ DOTATE PET-CT scan showed a hypodense right adrenal nodule measuring 36×22 mm, probably litho-fluid with heterogeneous but high somatostatin receptor expression (with SUVmax 35.4). Considering clinical features, laboratory and imaging tests results, a suspicion of hypercortisolaemia due to ectopic ACTH-producing pheochromocytoma was raised. The patient was qualified for right adrenalectomy. Before the surgery the patient was treated with doxazosin and metyrapone, received enteral feeding and protein supplementation as well as intensive insulin administration. Interestingly, on this treatment we not only observed decreased cortisol levels (leading to a transient adrenal insufficiency), but also decreased levels of ACTH (150 pg/ml) and metanephrines. A right-sided laparoscopic adrenalectomy was performed. Post-surgery, the patient did not require further antidiabetic medication, experienced gradual weight gain, improved well-being, and did not need glucocorticoid supplementation. Histopathological examination confirmed a pheochromocytoma (pT1 NX, PASS 3, GAPP 2), and considering the immediate cortisol suppression with metyrapone, spontaneous ACTH decrease pre-surgery, absence of secondary adrenal insufficiency, and negative ACTH staining of the tumor, pheochromocytoma-induced PCS was diagnosed.

Conclusions: The case underscores the unique manifestation of PCS induced by pheochromocytoma, evident through clinical, laboratory, and histopathological findings, and highlights the successful resolution through adrenalectomy and supportive care.