Ectopic Cushing's Syndrome in Pediatric Age

Background: Cushing's syndrome due to ectopic ACTH secretion is a rare clinical condition resulting from a dysregulated ACTH secretion by neuroendocrine tumors, which can have various localizations and different histological differentiations. The overall incidence of endogenous Cushing's syndrome is 0.7–2.4 per million people per year. Children account for just 10% of all new cases that are reported each year. Case Report:: When the patient first presented clinically, she was a 17-year-old girl who displayed symptoms of schizophrenia (delirium, psychotic episodes, and hallucinations). Blood tests showed diabetes mellitus and hypokalemia. She was also affected by high blood pressure and osteoporosis complicated by D9-D10 and L1-L5 vertebral collapses. For these reasons, she was treated with aripiprazole, insulin glargine, potassium chloride, spironolactone, enalapril, and calcium carbonate. After two months of treatment, she was referred to the pediatrician endocrinologist, who diagnosed hypercortisolism after prescribing hormone tests (Table 1). After receiving her diagnosis, she began taking 1000 mg of metyrapone and had a whole-body CT scan, which revealed bilateral adrenal hyperplasia. The results of the 68Ga-PET/DOTATOC and 18FDG-PET scans were negative. The clinical course was intermittent in the months that followed, with hypercortisolism and eucortisolism alternating. After one year of treatment, a 68Ga-PET/DOTATOC showed a nodule in the thymic lodge (Fig. 1). The patient underwent a thymectomy. Unfortunately, after surgery, she continued to have high levels of cortisol, for which she continued metyrapone 750 mg/die. 68Ga-PET/DOTATOC repeated three months after surgery showed again an uptake corresponding to the thymic lodge (Fig. 2). In order to remove the neuroendocrine lesion, she had a new surgery, which resulting a finally resolutive. ACTH levels were monitored before, during, and post-surgery (Table 2). The laboratory provided the ACTH results very quickly and thoracic surgeons waited for hormonal results before concluding the procedure. The adopted strategy permitted us to monitor the outcome of the surgery. Conclusion:: The heterogeneity of ectopic Cushing's syndrome makes diagnosis difficult. Treatment of ectopic Cushing's syndrome requires close clinical, biochemical, and instrumental observation. Metyrapone is a drug able to control hypercortisolism in a lasting way with a good level of safety. 68Ga-PET/DOTATOC proves to be a tracer with good sensitivity and specificity for the identification of ACTH-secreting neuroendocrine lesions. The short half-life of ACTH is found to be a strategy to monitor the complete surgical resection of the neuroendocrine lesion. A multidisciplinary approach improves therapeutic success and reduces the risk of recurrence.