Providing Optimal Preoperative Localization for Recurrent Parathyroid Carcinoma: A Combined Parathyroid Scintigraphy and Computed Tomography Approach

Abstract

PURPOSE: The incidence of parathyroid carcinoma is approximately 0.5% to 5% in patients with primary hyperparathyroidism. Recurrent parathyroid carcinoma is treated with surgical resection of all sites of disease to ameliorate systemic manifestations of hyperparathyroidism, primarily hypercalcemia. This study investigates the role of parathyroid scintigraphy and computed tomography (CT) imaging in recurrent parathyroid carcinoma. MATERIALS AND METHODS: A retrospective chart review was performed on 8 patients diagnosed with recurrent parathyroid carcinoma at our tertiary care institution between 1975 and 2001. Surgical reports, histopathology, parathyroid scintigraphy, and CT findings were recorded. Surgical reports and radiologic studies were compared for concordance of recurrence sites. RESULTS: There were 32 imaging studies before reoperation: 15 parathyroid scintigraphy and 17 CTs. Of 15 sites of recurrence potentially seen on scintigraphy, 10 were true-positive (67%). Of 17 sites of recurrence potentially seen on CT, 9 were true-positive (53%). Of the 8 false-negatives on CT, 7 of these recurrences were in the surgical bed (88%). There were 9 instances in which CT and scintigraphy were performed preoperatively for comparison and correlation. CT and scintigraphic findings were incongruent in 7 of 9 of these cases (78%). CONCLUSION: Successful surgical intervention for recurrent parathyroid carcinoma requires accurate preoperative localization studies and complete excision of metastases. Our data supports combined analysis of parathyroid scintigraphy and CT for patients with recurrent disease before reoperation. Additionally, our review suggests that sensitivity may be optimized with SPECT parathyroid scintigraphy and close correlation with CT.