HURTHLE CELL TUMOR DWELLING IN HOT THYROID-NODULES - PREOPERATIVE DETECTION WITH TECHNETIUM-99M-MIBI DUAL-PHASE SCINTIGRAPHY

Single injection dual-phase scintigraphy (early and late acquisitions) with Tc-99m-MIBI was used to differentiate benign and malignant hot t hyroid nodules. Methods: Thirteen euthyroid and two hyperthyroid patie nts displaying a hot thyroid nodule on the Tc-99m scan due to an auton omously functioning thyroid nodule (AFTN) underwent early (15-30 min) and late (3-4 hr) thyroid scintigraphy after the administration of 740 -1000 MBq (TC)-T-99m-MIBI. Visual scoring was done to assess nodular t racer uptake and retention. In addition, the nodular-to-thyroid (N/T) uptake ratio in the early and late image and the washout rates (WO) fr om the nodule and thyroidal tissue were measured. All patients underwe nt thyroid surgery. Results: Histopathology revealed a Hurthle cell tu mor in three nodules, a benign adenoma with oxyphilic metaplasia in tw o nodules and a benign adenoma without oxyphilic cells in the remainin g 10 nodules. The Hurthle cell tumor nodules displayed intense and per sistent uptake of Tc-99m-MIBI (N/T was 2.81 +/- 0.52 and 5.53 +/- 1.06 in early and late images, respectively; WO from the nodule was 12.33 +/- 0.47, WO from the thyroidal tissue was 22.00 +/- 3.56). The benign nodules showed intense uptake in the early image and intense uptake t o absent retention in the late image (N/T was 2.94 +/- 1.31 and 1.62 /- 0.50 in the early and late images, respectively; WO from the nodule was 20.25 +/- 2.92, WO from the thyroidal tissue was 20.33 +/- 2.92). Conclusion: Single injection dual-phase Tc-99m-MIBI scintigraphy of t he thyroid with AFTN can identify nodules as a result of the activity of a Hurthle cell tumor, since these tumors cause intense and persiste nt tracer uptake in contrast with a benign AFTN.