Nonequivalent results of tetrofosmin and sestamibi imaging of parathyroid tumors.
OBJECTIVE
To report the case of a patient with a large parathyroid carcinoma missed by dual-phase technetium Tc 99m tetrofosmin (TETRO) parathyroid scanning.


METHODS
We present the clinical findings, laboratory results, imaging studies, and surgical pathology report in a man with parathyroid carcinoma and review the literature regarding the use of TETRO scintigraphy in patients with hyperparathyroidism.


RESULTS
In an 83-year-old man with hyperparathyroidism, severe hypercalcemia developed in the context of nephrolithiasis. An in-office ultrasonographic evaluation of the neck revealed a partially calcified mass (2.3 by 1.3 by 1.6 cm) at the inferoposterior border of the left thyroid lobe. Technetium Tc 99m sestamibi (MIBI) scanning was requested and reported as "negative." In fact, TETRO scanning had been substituted for MIBI scanning by the management of the nuclear medicine facility. Before neck exploration, performance of dual-phase MIBI parathyroid scintigraphy revealed radionuclide retention in the left lower neck area at 120 minutes, in the same site as the ultrasonographically visualized mass. A limited left inferior parathyroidectomy was performed, and intraoperative parathyroid hormone levels declined from 254 pg/mL to 28 pg/mL 10 minutes after near-complete resection of the mass. Pathology evaluation of the surgical specimen revealed a 2,000-mg parathyroid carcinoma.


CONCLUSIONS
Although both agents incorporate the same technetium Tc 99m radionuclide, TETRO and MIBI parathyroid scanning are not equivalent in the detection of parathyroid tumors with use of the dual-phase technique. We do not recommend substitution of TETRO for MIBI as a cost-control measure in the evaluation of hyperparathyroidism.
Harrell
R Mack
RM
North Broward Hospital District, Imperial Point Medical Center, Ft. Lauderdale, Florida 33308, USA.
Mackman
Dennis M
DM
Bimston
David N
DN
D000369:Aged, 80 and over; D002277:Carcinoma / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D011877:Radionuclide Imaging / Q000379:methods*; D017256:Technetium Tc 99m Sestamibi
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; C078700:technetium tc-99m tetrofosmin; D017256:Technetium Tc 99m Sestamibi