Paraneoplastic Cushing's syndrome associated with bronchopulmonary carcinoid tumor in youth: A case report and review of the literature.

Paraneoplastic Cushing's syndrome (CushingPS) caused by bronchopulmonary carcinoid tumors presents a diagnostic challenge for clinicians. The present study reports the case of an 18-year-old male patient presenting with rapid weight gain, polyuria, polydipsia and progressive muscle weakness. Chemical and imaging findings suggested ectopic secretion of adrenocorticotropin. Whole-body fluorine-fluorodeoxyglucose (FDG-PET/CT) positron-emission tomography revealed an increased uptake of FDG-PET/CT in the right middle lung mass and lobar lymph node. Postoperative pathology confirmed the presence of a typical carcinoid, as well as a lobar lymph node metastasis. The patient underwent a right middle lobectomy with mediastinal lymph node resection, which resulted in symptom clearance, followed by rapid weight loss. No CushingPS or tumor recurrence was observed at the 3-month postoperative follow-up.