Parathyroid ectopia evidenced by 99mTc-sestamibi scintigraphy: Case report

Introduction The presence of an ectopic parathyroid gland is the most frequent cause of persistent hyperparathyroidism. Its detection constitutes a source of topographic diagnostic difficulties particularly for purely morphological explorations. The goal of this work is to elucidate the interest of scintigraphy using 99mTc-sestamibi in the diagnosis and the therapeutic orientation of ectopic parathyroid. Case report A 50-year-old patient was followed for persistent hyperparathyroidism after subtotal para thyroidectomy. The clinical examination was without particularity contrasting with an always high parathormone rate. Echography, computed tomography and magnetic resonance imaging were not conclusive. Scintigraphy carried out after intravenous injection of 740 MBq of sestamibi-Tc99m with acquisition of static images at 20 min and 2 h showed an area of high uptake in projection of the right upper mediastinum. The diagnosis of an ectopic parathyroid localization was retained. Resection and pathologic examination of the surgical specimen revealed parathyroid adenoma tissue. The evolution was marked by a normalisation of the rate of parathormone. Discussion 99mTc-sestamibi scintigraphy is a functional exploration with a higher sensitivity than the other morphological imaging techniques for preoperative topographic determination of ectopic parathyroid. It significantly contributes to an elective and more rapid surgical resection of these lesions. (authors)