Contribution of scintigraphy and ultrasonography to the prediction of malignancy in thyroid nodules with indeterminate cytology

Abstract

Objective: To evaluate the contribution of 131 I scintigraphy and ultrasonography to the prediction of malignancy in thyroid nodules with indeterminate cytology in euthyroid patients. Subjects and methods: The sample consisted of 102 patients with thyroid nodules, submitted to FNAC and presenting an indeterminate cytological diagnosis (follicular neoplasm). Results: Malignancy was observed in 19/25 (76%) nodules with suspicious ultrasonographic characteristics versus 5/77 (6.5%) without suspicious findings. When 131 I scintigraphy showed a cold or hot nodule, the chance of malignancy was 38.5% and 2.5%, respectively. This exam was inconclusive in 10% of the patients. Conclusions: Surgery is indicated when a thyroid nodule with indeterminate cytology exhibits suspicious ultrasonographic characteristics. Otherwise, 131 I scintigraphy can exclude thyroidectomy when reveals uptake in the nodule, which is observed in half the cases. Arq Bras Endocrinol Metab. 2010;54(1):56-9 Keywords Thyroid nodule; indeterminate cytology; radionuclide imaging; ultrasonography resumo Objetivo: Avaliar a contribuição da cintilografia com 131 I e da ultrassonografia na predição de malignidade em nódulos tireoidianos com citologia indeterminada em pacientes eutireoidianos. Sujeitos e Métodos: A amostra foi composta por 102 pacientes com nódulos tireoidianos submetidos à punção aspirativa com agulha fina (PAAF), apresentando citologia indeterminada (neoplasia folicular). Resultados: Malignidade foi encontrada em 19/25 (76%) nódulos suspeitos na ultrassonografia versus 5/77 (6,5%) naqueles sem características suspeitas. Quando a cintilografia com 131 I mostrou nódulo hipo-ou hipercaptante, a chance de malignidade foi 38,5% e 2,5%, respectivamente, e em 10% dos pacientes esse exame foi inconclusivo. Conclusões: Cirurgia está indicada quando um nódulo tireoidiano com citologia indeterminada exibe características ultrassonográficas suspeitas. Quando não as exibe, a cintilografia com 131 I pode dispensar a tireoidectomia se revelar captação correspondente ao nódulo, o que ocorre em metade dos casos. Arq Bras Endocrinol Metab. 2010;54(1):56-9

Value of Ultrasound and Cytological Classification System to Predict the Malignancy of Thyroid Nodules with Indeterminate Cytology

“…However, when it was analyzed, only the 378 (15% of 2,468) patients were surgically treated in that studied group; the distribution of diagnoses was 10% of unsatisfactory sample and 61.4% of follicular lesion [13], similar to our data featuring 56% of indeterminate results. According to the literature, the frequency of malignancy in thyroid nodules <3-4 cm with indeterminate cytology (follicular neoplasms) ranges from 10% to 30% [8,26,27], which is in agreement with our results.…”

“…Rosário et al [8] confirmed malignancy in 23.5% of patients with indeterminate cytology, and 19 of these 25 (76%) nodules had suspicious sonographic features (P<0.05), similar to our results. This group verified the impact of cold nodule detection by I131 scintigraphic to predict malignancy (P< 0.05) [8], but these data are not found in our results. Stojadinovic et al [31] studied 216 patients with thyroid nodules undergoing US, electrical impedance scanning, and FNAC prior to thyroidectomy [31].…”

“…Sonographic features have shown to be good predictors of malignancy in these lesions [6][7][8]. The majority of the existing clinical predictors of malignancy are not yet clear for this group of tumors.…”

“…Rosario et al [8] studied the ultrasound and scintigraphic parameters of malignancy in 102 indeterminate cytology cases. Malignancy was detected in 23.5% (24/102) of cases and was directly correlated to suspicious US features [8].…”

Thyroid nodules and differentiated thyroid cancer: update on the Brazilian consensus

“…The iodine radioisotopes are absorbed and organified by the thyroid and are the preferred isotypes because 3 to 8% of nodules that are hyperfunctioning when mapped with 99m Tc scans are hypofunctioning with iodine (36). Scintigraphy is also indicated for nodules with cytology, which is suggestive of follicular tumor in patients with normal low or low TSH, if it was not performed earlier (37).…”