CO31 | Ectopic mediastinal parathyroid adenoma: a rare case of primary hyperparathyroidism

Introduction: Prevalence of primary hyperparathyroidism (PH) is increasing. A single para-thyroid adenoma is the most frequent cause of PH. PH can also be due to ectopic mediastinal parathyroid adenoma in 11-25% of patients. To detect ectopic adenoma guidelines recommend use of ultrasound, Tc-99 m-sestamibi scintigraphy, and contrast-enhanced 4D CT. The use of endoscopic ultrasound (EUS) is reported in some case and some cases in has been integrated with fine-needle aspiration and PTH sampling in the eluate. Case report: A 66-year-old female was admitted for a spontaneous neck hematoma. Laboratory exams revealed PH with elevated total serum calcium 10,9 mg/dl and high PTH 150 pg/mL. Neck ultrasound did not show images compatible with parathyroid. CT revealed complex vascularization of thyroid and a nodule between posterior side of right thyroid lobe and paraesophageal region. A double-tracheant scintigraphy revealed a 15 mm nodule compatible with ectopic parathyroid. A echoendoscopy detected a dysomogeneus, hyperechoic and elonged lesion was noted, with iperenhancement using CEUS. FNAB was performed. Cytological exam revealed non-atypical epithelial aggregates, results at PTH+ and TTF1– at immunophenotypic investigations. PTH dosage on the washing liquid was >2500 pg/ml, diagnostic of ectopic parathyroid. Conclusions: In patients with PH, second and third level diagnostic procedures as in this case could be useful to be sure of diagnosis, particularly if pluricomorbid patients must receive parathyroidectomy with major surgery could include potential severe complications.