Radiological imaging is routinely used in patients with primary hyperparathyroidism to localize the abnormal adenoma and to plan surgical approach. We report an unusual cause of false-positive localization on parathyroid sestamibi scan, i.e., not previously described in the literature.

A 66-year-old man with primary hyperparathyroidism showed a discrete persistent focus in the left infraclavicular area during localization using sestamibi scan. Ultrasound of the neck was negative showing only small bilateral thyroid nodules. Single-photon emission and four-dimensional computed tomography (CT) scans showed an intense focus of the tracer uptake and a 1-cm lesion near the left subclavian vein (SCV), corresponding to the infraclavicular hot spot. Initial infraclavicular exploration showed the lesion to be a collapsible saccular varix of the left SCV. Bilateral neck exploration led to the discovery of the actual right parathyroid adenoma beneath an exophytic thyroid nodule. The patient made an uneventful recovery and remains normocalcemic at 1-year follow up.

Hot spot on parathyroid imaging outside the line of embryological descent should be interpreted with caution. Vascular retention of injected isotope within a saccular varix of the neck vein can give rise to falsepositive results on sestamibi scans. Bilateral neck exploration remains the “gold standard” procedure when localization scans either are negative or turn out to have false-positive findings.

Singaporewalla RM, Negi A, Seow DYB, Chinchure D. An Unusual Cause of Hot Spot on Parathyroid Imaging. World J Endoc Surg 2016;8(2):164-167.