S. Dream1, B. Lindeman1, H. Chen1 1University Of Alabama at Birmingham,Birmingham, Alabama, USA
Introduction:
Radioguided surgery has been an effective tool for identifying hyperfunctioning parathyroid glands, including both adenomas and hyperplastic glands during routine parathyroidectomy for hyperparathyroidism. The purpose of this study was to examine the role of radioguided surgery for the identification of intrathymic adenomatous and hyperplastic parathyroid glands.
Methods:
Between March 2001 to February 2018, 2291 patients underwent parathyroidectomy by one surgeon for primary hyperparathyroidism. Of these patients 158 (7%) were identified to have an ectopic intrathymic parathyroid gland. All patients underwent radioguided parathyroidectomy with preoperative injection of 10 mci of TC-99m sestamibi. Ex vivo radionuclide counts were used to confirm parathyroid excision with specimen radioactivity of >20% of the background level.
Results:
The mean age was 56 ±1 years with 74% of the patients being female. Preoperatively, 122 patients underwent sestamibi scan with the scan correctly identifying the the affected gland 61% of the time. Mean preoperative calcium was 10.7± 0.1 mg/dL and the mean preoperative parathyroid hormone(PTH) was 112 ± 6 pg/mL. Mean background radionuclide count was 208 +/-7, mean ex vivo radionuclide count was 127 ± 9, with ex vivo counts of removed glands were >20% in all patients. Thymectomy was performed in 140 of the patients. Mean postoperative calcium was 9.3 ± 0.1 mg/dL and the mean postoperative PTH was 46 ± 3 pg/mL.
All ectopic parathyroid glands were successfully identified using gamma probe. Ex vivo counts found to be significantly higher in patients with adenomas. Patients with parathyroid adenomas also were older in age and had higher preoperative calcium levels (see table). While 10% of patients with primary hyperparathyroidism have hyperplasia, 42% of patients with thymic parathyroids had hyperplasia.
Conclusion:
Radioguided parathyroidectomy is useful in detecting ectopic parathyroid glands in the thymus. Patients with hyperplasia disproportionately have thymic parathyroid glands.
