Pseudo-Cushing’s state in a patient with non-functioning pituitary adenoma

Abstract

© BMJ Publishing Group Limited 2021. No commercial reuse. See rights and permissions. Published by BMJ. DESCRIPTION A 65yearold Japanese woman was referred for investigation of hypertension. She had medical histories of osteoporosis, cataract and glaucoma, but no history of diabetes mellitus, polycystic ovary syndrome, depression or excessive alcohol intake. She had severe obesity (body mass index: 39.5 kg/m) and had suffered from continuous pain due to internal derangement of the knee for 2 weeks. Physical assessment revealed Cushing’s signs of moon face, buffalo hump and centripetal obesity (figure 1A). Both plasma adrenocorticotropin hormone (ACTH) and serum cortisol levels at 17:00 were high (77.9 pg/mL and 18.22 μg/dL, respectively). Pituitary contrastenhanced MRI showed a pituitary tumour (24×23×21 mm), suggesting adenoma (figure 2A). Adrenal CT showed normal shapes. These results indicated Cushing’s disease (CD), and she was admitted to our hospital 3 weeks later for thorough endocrinological examinations. Basal plasma ACTH and serum cortisol levels were normal (33.3 pg/mL and 11.4 μg/ dL, respectively) with preserved circadian rhythms (figure 2B). A 24hour urine collection showed a normal level of free cortisol (44.8 μg/ day), and overnight administration of 0.5 mg of dexamethasone reduced the serum cortisol level (0.7 μg/dL) (figure 2B). Results of stimulation tests for anterior pituitary hormones, including corticotropinreleasing hormone (CRH), gonadotropinreleasing hormone and thyrotropinreleasing hormone, were unremarkable (figure 2C). We made a provisional diagnosis of nonfunctioning pituitary adenoma in a pseudoCushing’s state (PCS), and endoscopic endonasal transsphenoidal surgery for the pituitary tumour was performed. Histopathology of the resected tumour confirmed pituitary adenoma with negative ACTH staining. PCS is a mimic condition of overt hypercortisolism; the differential diagnosis between CD and PCS can be very challenging. 2 Patients with obesity, metabolic syndrome, polycystic ovary syndrome, chronic alcoholism, depression and extreme physical stress are known to develop PCS. Obese patients have been reported to have hyperactivation of the hypothalamus– pituitary–adrenal (HPA) axis in response to both physical and psychosocial stressors, as in our patient. 2 4 The coincidental finding of