Endocrine Abstracts

Introduction: Cushing’s syndrome denotes pathologic hypercortisolism as a result of excessive adrenocorticotropic hormone (ACTH) production or autonomous adrenal production of cortisol according to the ACTH levels. However, 30% of the patients with CS have ACTH levels in the ‘grey zone’ (5–20 pg/ml), thereby posing a challenge in establishing the aetiological diagnosis.

Case presentation: A 20-year-old woman presented to our departement with the complaint of weight gain, facial plethora and spaniomenorrheaof 6 months duration. There was no previous medical or surgical history, no family history for endocrine disease. On examination, she had facial plethora, moon facies, centripetal obesity and purple striae on the abdomen and the four limbs. The rest of the exam was within normal limits. Investigations showedno suppression of cortisol after low dose dexamethasone confirming hypercortisolism. Early morning ACTH was 17,9 pg/ml. MRI of sella showed lesion on the left side of the pituitary measuring 5 mm. Since the ACTH level was in the gray zone, the dosage was controlled showing a low level (1,1 pg/ml) confirmed by a third ACTH sample (5,38 pg/ml). Computed tomography for adrenal gland showed a left adrenal mass, 4.4 cm in diameter (arrow), with a density of 30 Hounsfield units and a washout of contrast about 62% at 15 minutes. The diagnosis of pituitary ACTH-independent Cushing’s syndromewith pituitary incidentaloma was considered. The patient was subjected to surgery. The resected mass measured 5 cm. Histopathological examination was suggestive of adrenocorticaladenoma with modified Weiss score of 2/7.Postoperative hormonal evaluation showed 08:00 hours serum cortisol at 43.6 nmol/l and hydrocortisone supplementation was continued.

Discussion-conclusion: Cushing’s syndromeis a challenging disease to diagnose. The most common cause is Cushing’s disease accounting for 70–80% of the cases. Adrenal causes contribute 15–20%.The ACTH value of <5 pg/ml is suggestiveof ACTH-independent Cushing’s syndrome, while ACTH value of >20 pg/ml is suggestive of ACTH-dependent, and the levels between 5 and 20 pg/ml arein the ‘grey zone’. In this case, testsshould be repeated multiple times and clinicians should be cautious about the possibility of technical errors in any measuring systems. The presence of a pituitary microadenoma, if <6 mm in size, may be an incidental finding in this scenario and can be present in 3–27% of the healthy population. Therefore,multiple samplings for ACTH and adrenal imaging should be performed to exclude ACTH-independent CS.