Pre-operative localization and interventional treatment of parathyroid tumors: when and how?

A variety of diagnostic tests are currently used for parathyroid localization. In patients who have not had previous surgery, none of these are as sensitive or specific for the localization of abnormal parathyroid glands as an experienced surgeon. In these patients, no pre-operative localization procedures are normally needed. Patients who have had previous thyroid or parathyroid surgery require pre-operative localization. Noninvasive imaging procedures (ultrasound, scintigraphy, computed tomography, magnetic resonance imaging) should be performed until an abnormal gland is identified in the same location on at least 2 examinations. The order in which these studies are performed is not important. In the 50% to 70% of patients in whom noninvasive studies are inconclusive, suspicious lesions may be aspirated or biopsied with imaging guidance. If this cannot be done or is nondiagnostic, angiography and, if necessary, parathyroid venous sampling should be done. Intra-operative ultrasound examination of the neck is helpful during re-operations. In selected patients, parathyroid tumors may be ablated by injection of contrast material through an angiographic catheter into the artery supplying the gland, or by percutaneous injection of alcohol into the gland itself. Angiographic ablation is best used for mediastinal glands supplied by the internal thoracic artery or by a descending branch of the inferior thyroid artery. Percutaneous alcohol injection may injure the recurrent laryngeal nerve permanently and should be limited to the rare patient with a neck lesion who has a prohibitive surgical risk. Neither technique is as effective as surgery.