Focused parathyroidectomy without intra-operative parathormone monitoring: The value of PTH assay in preoperative ultrasound guided fine needle aspiration washout

BACKGROUND The accurate identification of hyperfunctioning parathyroid (HP) gland is the only issue for definitive surgical treatment in primary hyperparathyroidism (pHPT). Various imaging and operative techniques have been proposed to confirm the localization of the diseased gland. Nevertheless, none of these methods proved to be the gold standard. The presented study aimed to assess the value of parathyroid hormone assay in preoperative ultrasound guided fine needle aspiration (FNA)-PTH washout fluid to verify the correct localisation for focused parathyroidectomy without intra-operative PTH monitoring. MATERIAL AND METHODS The retrospective analysis of 57 patients with pHPT who underwent FNA-PTH was conducted from a prospective database. Biochemical assessment together with radiological (ultrasonography) and nuclear (MIBI scan) imaging was reviewed. Associations between FNA-PTH washout values and localization technics were evaluated and compared in terms of operative findings. RESULTS Focused parathyroidectomy without intraoperative PTH monitoring was performed to 45 patients with high FNA-PTH values. The median largest diameter of the target parathyroid lesion identified by ultrasonography was 13 mm (range, 6 to 36). The median serum PTH level was 190 pg/mL (range, 78 to 1709; reference range, 15 to 65) whereas the median washout PTH was 2500 pg/mL (range, 480 to 3389). According to operative findings high FNA-PTH levels correctly identified parathyroid adenoma in 40 cases (89% of sensitivity and 100% of specificity and positive predictive value) whereas MIBI scan localized the lesion in 36 of these cases (80% of sensitivity). CONCLUSIONS The higher level of PTH in preoperative ultrasound guided FNA washout is a considerable data to predict the correct localization of HP, particularly in circumstances of greater values than the serum PTH level. However, although its specificity is high, in cases of coexisting nodular thyroid disease, associated additional HP might be missed at focused parathyroidectomy without PTH monitoring, leading to recurrent disease.