C7 (Clinical Case) ACTH-dependent Cushing’s in an 8-Year-Old: A Diagnostic Challenge

Abstract Introduction/Background Cushing’s syndrome (CS) is rare, with 2-5 cases per million annually, and only 10% of these occurring in children. disease (CD) (excessive adrenocorticotropic hormone [ACTH] secretion by a pituitary source leading to hypercortisolism) the most common organic etiology CS children (75-90%). Ectopic ACTH (EAS), contrast, accounts for less than 1%. Case Description An 8-year-old male presented extensive vertebral compression fractures, rapid weight gain, headaches. He was found have hypertensive urgency (blood pressure 170/110 mmHg, > 99.9 percentile) Cushingoid features. Investigations revealed hypokalemia (2.0 mmol/L), elevated serum cortisol (1654 nmol/L, ref 85-620) 24-hour urine (27244 nmol/day, < 25). (35pmol/L, 1.6-13.9) confirmed ACTH-dependent CS. Although non-invasive dynamic testing (high dose dexamethasone suppression desmopressin stimulation tests) suggested an ectopic source, inferior petrosal sinus sampling (IPSS) source. Unfortunately, anatomical (3T MRI Sella) functional imaging (18 F-DOPA Gallium-68 dotatate PET/CT scans) not identified causative lesion date. On 18 imaging, 1cm focus avidity small bowel, concerning neuroendocrine tumour. However, excisional biopsy mass as Meckel’s diverticulum persistently post-operatively. As such, he has been started on ketoconazole control hypercortisolemia reduce morbidity. This mainly effective, reduced 70 nmol/day. will undergo serial continue medical therapy long tolerated. Exploratory surgery may be considered if proves ineffective or overly burdensome over time. Discussion We present diagnostically challenging case syndrome, suspected disease. Non-invasive tests limited sensitivity specificity when used isolation. result, localization can challenging. Ultimately, IPSS suggestive despite multiple modalities anatomic imaging. Medical useful temporizing measure while pursuing further workup, but problematic side effects requires frequent laboratory monitoring. patient’s story highlights difficulty diagnosis choosing management strategy patient without excess ACTH, all options carry risk Conclusion rare paediatrics should exam findings refractory hypertension. Diagnostic workup proceed sequential order confirm hypercortisolemia, distinguish between central vs peripheral origin, localize responsible lesion. In inconclusive investigations, remains necessary localization.