Impact of thyroid nodular disease on 99mTc-sestamibi scintigraphy in patients with primary hyperparathyroidism

Primary hyperparathyroidism with coexisting thyroid nodular disease (TND) has been considered a contraindication for selective parathyroidectomy because the low sensitivity of preoperative localization studies, especially 99(m)Tc-sestamibi scanning (MIBI) and ultrasound. The aim of this study was to assess the impact of concomitant TND in the preoperative image studies.

A total of 236 consecutive patients who had parathyroidectomy for sporadic hyperparathyroidism and the preoperative localization study that was done with MIBI were reviewed. Patients were divided into three groups: those who did not have any thyroid disease, those who had concomitant TND not necessary to resect, and those in whom thyroid resection due to TND was necessary at the time of parathyroidectomy.

MIBI showed a sensitivity of 78.5% in patients without concomitant TND, 73% in patients with TND but not thyroidectomy needed, and 54.5% in the cases that thyroid resection was necessary. When MIBI and ultrasound were both suspicious for an adenoma, the sensitivity was not influenced by the TND.

In patients with coexisting thyroid disease but not thyroidectomy needed, MIBI scintigraphy contributes to the detection of a solitary adenoma. When thyroid resection is required, MIBI imaging is often negative.