[Diagnostic strategy in persistent hyperparathyroidism. Report of two cases and review of the literature].

Ectopic adenoma is the main cause of surgery failure in the treatment of primary hyperparathyroidism (HPT). Localization of the abnormal glands is therefore necessary before a reoperation. We report two cases illustrating the interest of MRI and selective venous sampling of parathormone. In two patients with persistent hyperparathyroidism, ultrasound and sestamibi scanning failed to localize the ectopic glands. MRI suggested the presence of an adenoma in the mediastinum for the first patient and inside the thyroid for the second. In both cases, the localisation was confirmed by venous sampling and the reoperation was a success. We review the recent literature on this topic and we propose a diagnostic approach of persistent HPT.