[Incidence of malignant lesions in patients with clinically benign thyroid nodules: observational and prospective study in a cohort of 50 patients followed during two years]. / Incidência de malignidade na doença nodular da tiróide com baixa suspeita clínica: estudo observacional prospectivo por dois anos numa coorte de 50 pacientes.

INTRODUCTION: To study the frequency of malignant lesions in patients with clinically benign thyroid nodules and the value of the repetition of fine needle aspiration biopsy (FNAB). METHODS: Observational and prospective 2-year study in a cohort of 50 patients with clinically benign thyroid nodules. Patients were initially submitted to clinical examination, ultrasound (US) and FNAB1 patients, followed by a second FNAB and US. RESULTS: Palpation is not a good test for diagnosis and follow-up of thyroid nodules. On the other hand, the initial consideration that these patients should harbor benign lesions is a very useful parameter, since 47/50 patients (94%) did not present malignant lesions during the follow-up. FNAB1 and FNAB2 were concordant in 33/39 patients when FNAB1 was negative (85%); 11 patients were operated, 8 by suspicious FNAB and 3 due to nodule growth. We observed 2 patients with non-invasive papillary microcarcinoma and 1 patient with papillary carcinoma outside of the main nodules. CONCLUSION: there was concordance between initial clinical benign diagnosis, FNAB and the follow-up. In one case there was a papillary carcinoma. In addition, ultrasonography should be considered for all patients with suspected thyroid nodules. Finally, we demonstrated that a second cytology usually confirms the result of the first cytology in benign thyroid nodules.

Basal serum thyroglobulin measured by a second-generation assay is equivalent to stimulated thyroglobulin in identifying metastases in patients with differentiated thyroid cancer with low or intermediate risk of recurrence.

BACKGROUND: Guidelines for the follow-up of differentiated thyroid cancer (DTC) recommend the measurement of TSH-stimulated thyroglobulin (s-Tg) instead of basal Tg on T4 therapy (b-Tg). However, these guidelines were established using first-generation Tg assays with a functional sensitivity (FS) of 0.5-1.0 ng/ml. Current more sensitive second-generation Tg assays (Tg2G; FS 0.05-0.10 ng/ml) have shown that low-risk DTC patients with undetectable b-Tg rarely have recurrences. OBJECTIVES: This study was undertaken to compare b-Tg using a chemiluminescent Tg2G assay (Tg2GICMA; FS 0.1 ng/ml) with s-Tg in DTC patients with an intermediate risk of recurrence. METHODS: We evaluated 168 DTC patients with a low (n = 101) and intermediate (n = 67) risk of recurrence treated by total thyroidectomy (147 also treated with radioiodine), with a mean follow-up of 5 years. RESULTS: b-Tg was undetectable with the Tg2GICMA in 142 of 168 patients. s-Tg was <2 ng/ml in 138 of these 142 patients, and only 3 of these 138 (2%) presented metastases on cervical ultrasound (US). Of the 4 of 142 patients with s-Tg >2 ng/ml, 1 had cervical metastases seen after radioiodine. Furthermore, 26 of 168 patients presented detectable b-Tg with the Tg2GICMA; 17 of these 26 patients also presented s-Tg >2 ng/ml. In 10 of these 17 patients, metastases were detected. Cervical US or b-Tg were positive in 14 of 15 patients with recurrent disease. Globally, the sensitivity and negative predictive value of the Tg2GICMA plus US were 93 and 99%, respectively. CONCLUSION: b-Tg measured with a Tg2GICMA and cervical US, used together, are equivalent to s-Tg in identifying metastases in patients with DTC with a low or intermediate risk of recurrence.

Development of a sensitive and specific quantitative reverse transcription-polymerase chain reaction assay for blood thyroglobulin messenger ribonucleic acid in the follow-up of patients with differentiated thyroid carcinoma.

CONTEXT: Serum thyroglobulin is a sensitive tumor marker in the follow-up of patients with differentiated thyroid carcinoma (DTC), but the presence of endogenous anti-thyroglobulin antibodies (TgAb) can interfere on its measurement. To prevent interference by TgAb, several investigators have tried to quantify blood mRNA Tg by real-time RT-PCR, but the results have been variable, not reporting a correlation between mRNA Tg and the presence of metastases. OBJECTIVE: The aim of the study was to evaluate the development of a sensitive and specific quantitative RT-PCR assay for blood mRNA Tg in the follow-up of patients with DTC. DESIGN AND PATIENTS: An assay employing primers located in a region not affected by alternative splicing or single nucleotide polymorphisms was developed to study 104 DTC patients (13 of 104 with positive TgAb). RESULTS: The assay is specific for thyroid tissue because we found mRNA Tg expression in normal thyroid tissue, but we did not find any mRNA Tg expression in any extrathyroidal tissues. Quantitative mRNA Tg levels were significantly different between patients "free of disease" (82 of 104) and those with metastases (22 of 104) (2.61 +/- 0.26 vs. 27.58 +/- 1.62 pg mRNA Tg/microg RNA) (P < 0.0001). A cutoff point of 5.51 was able to discriminate between the two groups. In addition, the measurement of mRNA Tg was not affected by the presence of TgAb. CONCLUSION: This new mRNA Tg quantification is a reliable method that allowed us to differentiate patients free of disease from those with metastases, and it could represent an appropriate molecular marker for the follow-up of patients with DTC, especially those with positive TgAb.

Incidência de malignidade na doença nodular da tiróide com baixa suspeita clínica: estudo observacional prospectivo por dois anos numa coorte de 50 pacientes / Incidence of malignant lesions in patients with clinically benign thyroid nodules: observational and prospective study in a cohort of 50 patients followed during two years

OBJETIVOS: Verificar a ocorrência de lesões malignas em pacientes com nódulos tiroidianos clinicamente benignos e o valor da repetição da citologia aspirativa da tiróide (PAAF). MÉTODOS: Estudo observacional prospectivo por 2 anos em coorte de 50 mulheres com nódulos tiroidianos clinicamente benignos, com exame clínico, ultra-sonografia (US) e PAAF inicial, seguidas por acompanhamento clínico, US e repunção dos mesmos nódulos (PAAF2). RESULTADOS: A palpação não é bom método para o seguimento dos nódulos quando comparada ao US. O quadro clínico foi parâmetro de confiança, pois 47/50 pacientes (94 por cento) evoluíram sem malignidade durante o seguimento. PAAF1 e PAAF2 concordaram em 33/39 pacientes quando PAAF1 foi negativa (85 por cento); 11 pacientes foram operadas, 8 por PAAF suspeita e 3 por aumento do volume nodular durante o seguimento. O anátomo-patológico (AP) foi benigno nas lesões suspeitas (8 adenomas e 3 bócios colóides). Houve 2 casos de microcarcinoma papilífero não invasivo em área distante dos nódulos e 1 caso de carcinoma papilífero não invasivo em bócio multi-nodular. CONCLUSÕES: Houve concordância entre características clínicas de benignidade com PAAF, US e acompanhamento clínico ou cirurgia; numa paciente encontramos carcinoma papilífero. O US deve ser considerado em pacientes com suspeita de nódulos de tiróide ao exame clínico; na maioria das vezes quando o resultado da PAAF1 é negativo para malignidade, o segundo exame citológico confirma o primeiro.

Análise critica de dois radioimunoensaios segmento-específico para a medida de paratormônio no diagnóstico de hiperparatiroidismo primário

Foram estudados os resultados obtidos com dois radioimunoensaios segmento-específicos para a medida de paratormônio sérico, um aminoterminal e outro carboxiterminal, em 29 pacientes com hiperparatiroidismo primário comprovado. Os resultados foram comparados com os observados em 69 indivíduos normais e em dez pacientes com hipercalcemia näo relacionada a hiperparatiroidismo primário. Analisando-se a capacidade de detecçäo de hiperparatiroidismo primário no universo de pacientes com hipercalcemia, o método aminoterminal específico mostrou sensibilidade de 82,8% e especificidade de 100%, enquanto que com o carboxiterminal obtivemos 59 e 70%, respectivamente. Os autores concluem que a medida do paratormônio, através de um ensaio específico para a porçäo biologicamente ativa (aminoterminal) é de maior valor diagnóstico, ressalvando-se a necessidade da dosagem concomitante da calcemia