D. J. Goldberg1, J. Monchik1, T. Cotton1 1Brown University School Of Medicine,General Surgery,Providence, RI, USA
Introduction:
Giant parathyroid adenomas are poorly defined in the literature. There is limited data regarding preoperative localization and the incidence of multiglandular disease. The purpose of this study is to determine the utility of preoperative localization using ultrasound and sestamibi, as well as the incidence of multiglandular disease, in patients with a giant parathyroid adenoma.
Methods:
A retrospective review identified 870 patients who underwent surgery for primary hyperparathyroidism (PHPT) from January 2003 to September 2013. A giant parathyroid adenoma, defined as a single gland with a weight >2 grams, was identified in 78 patients. Seven hundred ninety-two patients had adenomas <2 grams and were placed in the non-giant adenoma group. All patients underwent ultrasound and sestamibi for preoperative localization. Ultrasound and sestamibi results were compared with operative findings. The criteria for completion of surgery was an intraoperative parathyroid hormone fall of 50% from the highest level and into the normal range 10 minutes following parathyroid gland resection. Accuracy of various localization techniques, as well as the incidence of multiglandular disease, was then compared between groups.
Results:
In the giant adenoma group (>2 grams), surgery identified a single adenoma in 70/78 patients (89.7%) and double adenoma in 8/78 (10.3%). There was no incidence of four gland hyperplasia. In the non-giant adenoma group, surgery identified a single adenoma in 683/792 patients (86.2%), double adenoma in 88/792 (11.1%), and 4 gland hyperplasia in 21/792 (2.7%). Giant adenomas were correctly localized by ultrasound in 60/78 patients (77%) compared to the non-giant adenoma group with 518/780 patients (66%, p=0.07). Giant adenomas were correctly localized by sestamibi in 72/78 patients (92%) compared to the non-giant adenoma group with localization of 618/785 patients (79%, p=0.002). Within the giant adenoma group alone, sestamibi was significantly more accurate at localizing the giant adenoma when compared with ultrasound (92% vs 77%, p=0.01). Of the 8 patients with a double adenoma in the giant adenoma group, 4/8 (50%) correctly localized one of the two adenomas by ultrasound compared to 7/8 (88%) with sestamibi (p=0.28).
Conclusion:
Giant parathyroid adenomas are reasonably common, occurring in 9% of parathyroidectomies for PHPT over a 10 year period. While 10.3% of giant adenoma patients had a double adenoma, none had four gland hyperplasia. Patients with a giant adenoma localized better with sestamibi than ultrasound and were more likely to localize with either modality than patients with non-giant adenomas.