ABSTRACT Objective: A primary medical relevance of thyroid nodules consists of excluding thyroid cancer, present in approximately 5% of all thyroid nodules. Fine-needle aspiration biopsy (FNAB) has a paramount role in distinguishing benign from malignant thyroid nodules due to its availability and diagnostic performance. Nevertheless, intraoperative frozen section (iFS) is still advocated as a valuable tool for surgery planning, especially for indeterminate nodules. Subjects and methods: To compare the FNAB and iFS performances in thyroid cancer diagnosis among nodules in Bethesda Categories (BC) I to VI. The performance of FNAB and iFS tests were calculated using final histopathology results as the gold standard. Results: In total, 316 patients were included in the analysis. Both FNAB and iFS data were available for 272 patients (86.1%). The overall malignancy rate was 30.4%% (n = 96). The FNAB sensitivity, specificity, and accuracy for benign (BC II) and malignant (BC V and VI) were 89.5%, 97.1%, and 94.1%, respectively. For all nodules evaluated, the iFS sensitivity, specificity, and accuracy were 80.9%, 100%, and 94.9%, respectively. For indeterminate nodules and follicular lesions (BC III and IV), the iFS sensitivity, specificity, and accuracy were 25%, 100%, and 88.7%, respectively. For BC I nodules, iFS had 95.2% of accuracy. Conclusion: Our results do not support routine iFS for indeterminate nodules or follicular neoplasms (BC III and IV) due to its low sensitivity. In these categories, iFS is not sufficiently accurate to guide the intraoperative management of thyroidectomies. iFS for BC I nodules could be an option and should be specifically investigated

OBJETIVO: O objetivo deste estudo foi avaliar a acurácia da dosagem de tireoglobulina no lavado da agulha da punção aspirativa (PAAF-Tg) de linfonodos (LN) cervicais para detecção de metástases do câncer papilar de tireoide (CPT). SUJEITOS E MÉTODOS: Foram incluídos 43 pacientes (51,4 ± 14,6 anos) com diagnóstico de CPT e evidência de LN cervicais aumentados. Os LN suspeitos foram submetidos à punção aspiração com agulha fina guiada por ecografia para análise citológica e dosagem de tireoglobulina (PAAF-Tg). RESULTADOS: A mediana dos valores de PAAF-Tg nos LN metastáticos (n = 5) foi 3.419,0 ng/mL (11,1-25.538), enquanto nos LN não metastáticos (n= 38) a mediana foi de 3,7 ng/mL (0,8-7,4). Utilizando-se o nível de 10 ng/mL como ponto de corte, observaram-se sensibilidade e especificidade de 100%. Os níveis de TSH sérico não interferiram na dosagem de PAAF-Tg (3,3 e 3,8 ng/mL nos grupos com TSH supresso (TSH 0,07 mUI/mL) e hipotireoidismo (TSH 97,4 mUI/mL), respectivamente, P = 0,2). CONCLUSÃO: Os resultados demonstram que a dosagem de PAAF-Tg é uma ferramenta importante no diagnóstico de metástases do CPT, podendo ser utilizada independente do "status" tireoidiano.

OBJECTIVE: The aim of this study was to evaluate the accuracy of the measurement of thyroglobulin in washout needle aspiration biopsy (FNAB-Tg) to detect papillary thyroid cancer (PTC) metastases. SUBJECTS AND METHODS: Forty-three patients (51.4 ± 14.6 years) with PTC diagnosis and evidence of enlarged cervical lymph nodes (LN) were included. An ultrasound-guided fine-needle aspiration of suspicious LN was performed, for both cytological examination and measurement of FNAB-Tg. RESULTS: The median values of FNAB-Tg in patients with metastatic LN (n = 5) was 3,419 ng/mL (11.1-25,538), while patients without LN metastasis (n = 38) showed levels of 3.7 ng/mL (0.8-7.4). Considering a 10 ng/mL cutoff value for FNAB-Tg, the sensitivity and specificity was 100%. There were no differences on the median of FNAB-Tg measurements between those on (TSH 0.07 mUI/mL) or off levothyroxine (TSH 97.4 mUI/mL) therapy (3.3 vs. 3.8 ng/mL, respectively; P = 0.2). CONCLUSION: The results show that evaluation of FNAB-Tg in cervical LN is a valuable diagnostic tool for PTC metastases that can be used independent of the thyroid status.