Rendimiento del sistema Bethesda en el diagnóstico citopatológico del nódulo tiroideo en un centro universitario (Hospital de Clínicas) de Uruguay, diez años de experiencia / Performance of the Bethesda SYSTEM in the cytopathological diagnosis of the thyroid nodule in a university center (Hospital de Clínicas) in Uruguay, ten years of experience / Desempenho do sistema Bethesda no diagnóstico citopatológico de nódulos tireoidianos em um centro universitário (Hospital de Clínicas) no Uruguai, dez anos de experiencia

Resumen: Introducción: el estudio citológico por punción ecoguiada se caracteriza por ser rápido, confiable, mínimamente invasivo y rentable. Permite reducir procedimientos quirúrgicos innecesarios y clasifica apropiadamente a los pacientes con nódulos sospechosos o malignos para una intervención quirúrgica oportuna. Objetivo: el objetivo del presente estudio es evaluar la correlación citológica-anatomopatológica del sistema Bethesda en un centro universitario (Hospital de Clínicas) de Uruguay. Metodología: se realizó un estudio de tipo observacional, retrospectivo, descriptivo, basado el análisis de historias clínicas de pacientes sometidos a cirugía tiroidea en el Hospital de Clínicas, en el período comprendido entre enero de 2008 y diciembre de 2018. Resultados: del total inicial de 119 pacientes, 93 cumplieron los criterios de inclusión. El rango de edad de la muestra fue entre 15 y 79 años. Del total de puncionados 49,5% (46) fueron informados como benignos y 50,5% (47) como malignos. Se calculó en forma global una sensibilidad de 96% (0,96) con IC 1,0-0,90, especificidad de 98% (0,97) con IC 1,0-0,93, un VPP de 98% y VPN de 96%. La sensibilidad diagnóstica para la categoría IV, V y VI fue de 96%, con una especificidad de 100, 94 y 100% respectivamente. Conclusiones: el sistema Bethesda aplicado a las PAAF de nódulos tiroideos potencia la certeza diagnóstica y asiste en la decisión terapéutica. En nuestra institución contamos con una buena correlación citopatológica, similar a otros trabajos reportados en la literatura, lo que permite predecir adecuadamente el riesgo de malignidad y facilitar la toma de decisiones.

Summary: Introduction: the ultrasound-guided fine needle aspiration biopsy (FNAB) study is characterized by being fast, reliable, minimally invasive, and cost-effective. It reduces unnecessary surgical procedures and appropriately classifies patients with suspicious or malignant nodules for timely surgical intervention. Objective: the objective of this study is to evaluate the cytological-pathological correlation of the Bethesda System in a university center (Hospital de Clínicas) in Uruguay. Methodology: an observational, retrospective, descriptive study was carried out, based on the analysis of medical records of patients undergoing thyroid surgery at the Hospital de Clínicas, in the period between January 2008 and December 2018. Results: of the initial total of 119 patients, 93 met the inclusion criteria. The age range of the sample was between 15 and 79 years. Of the total of punctured, 49.5% (46) were reported as benign and 50.5% (47) as malignant. A sensitivity of 96% (0.96) with CI 1.0-0.90, specificity of 98% (0.97) with CI 1.0-0.93, a PPV of 98% and NPV of 96%. The diagnostic sensitivity for categories IV, V and VI was 96% with a specificity of 100, 94 and 100% respectively. Conclusions: the Bethesda system applied to FNA of thyroid nodules enhances diagnostic certainty and assists in the therapeutic decision. In our institution we have a good cytopathological correlation, similar to other works reported in the literature. This makes it possible to adequately predict the risk of malignancy and facilitate decision-making.

Resumo: Introdução: o estudo citológico por punção guiada por ultrassom caracteriza-se por ser rápido, confiável, minimamente invasivo e de baixo custo. Permite reduzir procedimentos cirúrgicos desnecessários e classificar adequadamente pacientes com nódulos suspeitos ou malignos para intervenção cirúrgica oportuna. Objetivo: avaliar a correlação citológico-patológica do Sistema Bethesda em um centro universitário (Hospital de Clínicas) no Uruguai. Metodologia: foi realizado um estudo observacional, retrospectivo, descritivo, baseado na análise de prontuários de pacientes submetidos à cirurgia de tireoide no Hospital de Clínicas, no período janeiro de 2008-dezembro de 2018. Resultados: do total inicial de 119 pacientes, 93 preencheram os critérios de inclusão. A faixa etária da amostra foi entre 15 e 79 anos. Do total de punções, 49,5% (46) foram relatadas como benignas e 50,5% (47) como malignas. No geral, uma sensibilidade de 96% (0,96) com IC 1,0-0,90, uma especificidade de 98% (0,97) com IC 1,0-0,93, um VPP de 98% e VPN de 96%. A sensibilidade diagnóstica para as categorias IV, V e VI foi de 96% com especificidade de 100, 94 e 100%, respectivamente. Conclusões: o sistema Bethesda aplicado à PAAF de nódulos tireoidianos aumenta a certeza diagnóstica e auxilia na decisão terapêutica. Em nossa instituição temos uma boa correlação citopatológica, semelhante a outros trabalhos relatados na literatura. Isso permite prever adequadamente o risco de malignidade e facilitar a tomada de decisão.

Utilidad para médicos no radiólogos de la clasificación tirads y las características ecográficas de los nódulos tiroideos / Usefulness for non radiologist physicians of tirad classification and ecographic characteristics of thyroid nodules

Dada la mayor accesibilidad a la ecografía tiroidea, se diagnostican más nódulos de forma incidental aumentando su prevalencia al 65% en las tres últimas décadas. Todo ello ha supuesto un aumento de punciones innecesarias. El objetivo de nuestro estudio es identificar la utilidad de la clasificación TIRADS y de las características ecográficas de los nódulos tiroideos para establecer la probabilidad de malignidad de los mismos y seleccionar aquellos sospechosos para realizar la punción y aspiración con aguja fina (PAAF). Se encontró una relación estadísticamente significativa entre la malignidad y nódulo sólido, hipoecogenicidad, márgenes irregulares y microcalcificaciones. Sin embargo, no se encontró relación estadísticamente significativa entre malignidad y número de nódulos, tamaño nodular, diámetro craneocaudal y vascularización central. Asimismo, un 26.1% de los nódulos TIRADS-2 (todos ellos microcarcinomas), un 30% de los TIRADS-3 y un 54 % de los TIRADS-4 fueron malignos (p 0.027). Tanto el TIRADS como las características ecográficas aisladas son útiles para identificar nódulos sugerentes de malignidad.

Owed to the easier accessibility to thyroid ecography, more incidental nodules are discovered reaching their prevalence the 65 % of population in the last three decades. All of it has resulted in a growth of unnecessary fine needle aspirations (FNA). Our study objective is to identify the TIRADS classification utility and the nodules sonographic characteristics to establish their probability of malignancy and to select those suspicious susceptible of FNA. We found a statistically significant relationship between malignancy and solid nodule, hypoechogenicity, irregular margins and microcalcifications. However we didn´t find a relation between malignancy and number, size, shape (taller than wide) and central vascularity. With respect to TIRADS classification, 26,1% of TIRADS-2 (all of them microcarcinomas), 30% of TIRADS-3 and 54% of TIRADS-4 were malignant (p: 0,027). Both of them, TIRADS and individual sonographic characteristics are useful to identify nodules suspicious of malignancy.

Is thyroid nodule volume predictive for malignancy?

ABSTRACT Objective: We aimed to determine the roles of preoperative thyroid nodule diameter and volume in the prediction of malignancy. Subjects and methods: The medical records of patients who underwent thyroidectomy between January 2007 and December 2014 were reviewed. The nodule diameters were grouped as < 1 cm, 1-1.9 cm, 2-3.9 cm and ≥ 4 cm, and volume was grouped as > 5 cm3, 5-9.9 cm3 and > 10 cm3. ROC (Receiver Operating Characteristic) curve analysis was performed to find the optimal cutoff value of diameter and volume that can predict malignancy. Results: There were 5561 thyroid nodules in 2463 patients. Five hundred and forty (9.7%) nodules were < 1 cm, 2,413 (43.4%) were 1-1.9 cm, 1,600 (28.8%) were 2-3.9 cm and 1,008 (18.1%) were ≥ 4 cm. Malignancy rates were 25.6%,10.6%, 9.7% and 8.5% in nodules < 1 cm, 1-1.9 cm, 2-3.9 cm and ≥ 4 cm, respectively. When classified according to volume, 3,664 (65.9%) nodules were < 5 cm3, 594 (10.7%) were 5-9.9 cm3 and 1,303 (23.4%) were ≥ 10 cm3. The malignancy rates were 12.7%, 11.4% and 7.8% for the nodules < 5 cm3, 5-9.9 cm3 and ≥ 10 cm3, respectively (p < 0.001). In ROC curve analysis, an optimal cutoff value for diameter or volume that can predict malignancy in all thyroid nodules or nodules ≥ 4 cm could not be determined. Conclusion: In this surgical series, malignancy risk did not increase with increasing nodule diameter or volume. Although the volume of malignant nodules ≥ 4 cm was higher than that of benign nodules ≥ 4 cm, there was no optimal cutoff value. The diameter or volume of the nodule cannot be used to predict malignancy or decide on surgical resection.

Modelo ambulatorial de atendimento de nódulo de tireoide / Ambulatory care model thyroid nodule

A prevalência de detecção de nódulos na tireoide através da palpação é de aproximadamente 5%. Essa prevalência sobe para 19 a 67% quando utilizada a avaliação ecográfica. A importância da avaliação clínica dessa entidade está na necessidade de diagnosticar o câncer de tireoide que ocorre em 5 a 10% dos casos. O relato descreve o perfil dos atendimentos realizados no ambulatório de nódulos de tireoide do Hospital Municipal Dr. Mário Gatti no período de 01/05/17 a 27/07/18 de pacientes que tiveram diagnóstico ultrassonográfico de nódulo de tireoide e realizaram punção aspirativa por agulha fina, a fim de inferir a respeito da capacidade de resolutividade do ambulatório interdisciplinar (endocrinologia e cirurgia de cabeça e pescoço) no diagnóstico e tratamento do câncer de tireoide. A organização do ambulatório com atendimento integral e por equipe multidisciplinar, possibilita uma melhora na qualidade assistencial além de ser elemento facilitador para o ensino, aprendizado e pesquisa. (AU)

The rate of thyroid node detection by touch is approximately 5%. This rate goes up to a range between 19 and 67% when a sonographic evaluation is used. The importance of the clinical evaluation of those thyroid nodes is within the need of diagnosing the cancer that occurs in 5 to 10% of the cases. This paper describes the profile of consultations performed at the Outpatient Clinic Thyroid Node Unit of the Municipal Hospital Dr. Mário Gatti (HMMG) from 01/05/17 to 07/27/18, of patients who had ultrasonographic diagnostics of thyroid node and underwent fine-needle aspiration, in order to draw conclusions about the capacity of the interdisciplinary clinic (Endocrinology and Head and Neck surgery) to diagnose and treat thyroid cancer effectively. The organization of the outpatient clinic, with comprehensive care and multidisciplinary team, enables an improvement in medical assistance as well as facilitating teaching, learning and research. (AU)

Malignancy rates for Bethesda III subcategories in thyroid fine needle aspiration biopsy (FNAB)

OBJECTIVES: Most thyroid diseases are nodular and have been investigated using ultrasound-guided fine needle aspiration biopsy (FNAB), the reports of which are standardized by the Bethesda System. Bethesda category III represents a heterogeneous group in terms of lesion characteristics and the malignancy rates reported in the literature. The objective of the present study was to evaluate the differences in the malignancy rates among Bethesda III subcategories. METHODS: Data from 1,479 patients who had thyroid surgery were reviewed. In total, 1,093 patients (89.6% female, mean age 52.7 (13-89) years) were included, and 386 patients were excluded. FNAB results (based on Bethesda Class) and histopathological results (benign or malignant) for coincident areas were collected. Bethesda III patients were subcategorized according to cytopathological characteristics (FLUS: follicular lesion of undetermined significance, Bethesda IIIA; AUS: atypia of undetermined significance, Bethesda IIIB). Data were correlated to obtain the malignancy rates for each Bethesda category and the newly defined subcategory. RESULTS: FNAB results for these patients were as follows: Bethesda I: 3.1%; Bethesda II: 18.6%; Bethesda III: 35.0%; Bethesda IV: 22.1%; Bethesda V: 4.1%; and Bethesda VI: 17.1%. The malignancy rates for Bethesda Class IIIB were significantly higher than those for Bethesda Class IIIA (p<0.001) and Bethesda Class IV (p<0.001). Bethesda Class IIIA showed significantly lower malignancy rates than Bethesda Class III overall (p<0.001) CONCLUSIONS: Improvements of the Bethesda System should consider this subcategorization to better reflect different malignancy rates, which may have a significant impact on the decision-making process.

Likelihood of malignancy in thyroid nodules according to a proposed Thyroid Imaging Reporting and Data System (TI-RADS) classification merging suspicious and benign ultrasound features

ABSTRACT Objective The aim of this study was to describe the ultrasound features of benign and malignant thyroid nodules and evaluate the likelihood of malignancy associated with each feature according to the Bethesda System for Reporting Thyroid Cytopathology and histopathology. With this analysis, we propose a new TI-RADS classification system. Materials and methods The likelihood of malignancy from ultrasound features were assessed in 1413 thyroid nodules according to the Bethesda System for Reporting Thyroid Cytopathology and histopathological findings. A score was established by attributing different weights to each ultrasound feature evaluated. Results Features positively associated with malignancy in bivariate analysis received a score weight of +1. We attributed a weight of +2 to features which were independently associated with malignancy in a multivariate analysis and +3 for those associated with the highest odds ratio for malignancy (> 10.0). Hence, hypoechogenicity (graded as mild, moderate or marked, according to a comparison with the overlying strap muscle), microcalcification and irregular/microlobulated margin received the highest weights in our scoring system. Features that were negatively associated with malignancy received weights of -2 or -1. In the proposed system a cutoff score of 2 (sensitivity 97.4% and specificity 51.6%) was adopted as a transition between probably benign (TI-RADS 3) and TI-RADS 4a nodules. Overall, the frequency of malignancy in thyroid nodules according to the categories was 1.0% for TI-RADS 3, 7.8% for TI-RADS 4a, 35.3% for TI-RADS 4b, and 84.7% for TI-RADS 5. Conclusion A newly proposed TI-RADS classification adequately assessed the likelihood of malignancy in thyroid nodules.

Correlation of Thyroid Imaging Reporting and Data System [TI-RADS] and fine needle aspiration: experience in 1, 000 nodules / Correlação entre a classificação Thyroid Imaging Reporting and Data System [TI-RADS] e punção aspirativa por agulha fina: experiência com 1. 000 nódulos

ABSTRACT Objective To correlate the Thyroid Imaging Reporting and Data System (TI-RADS) and the Bethesda system in reporting cytopathology in 1,000 thyroid nodules. Methods A retrospective study conducted from November 2011 to February 2014 that evaluated 1,000 thyroid nodules of 906 patients who underwent ultrasound exam and fine needle aspiration. Results A significant association was found between the TI-RADS outcome and Bethesda classification (p<0.001). Most individuals with TI-RADS 2 or 3 had Bethesda 2 result (95.5% and 92.5%, respectively). Among those classified as TI-RADS 4C and 5, most presented Bethesda 6 (68.2% and 91.3%, respectively; p<0.001). The proportion of malignancies among TI-RADS 2 was 0.8%, and TI-RADS 3 was 1.7%. Among those classified as TI-RADS 4A, proportion of malignancies was 16.0%, 43.2% in 4B, 72.7% in 4C and 91.3% among TI-RADS 5 (p<0.001), showing clear association between TI-RADS and biopsy results. Conclusion The TI-RADS is appropriate to assess thyroid nodules and avoid unnecessary fine needle aspiration, as well as to assist in making decision about when this procedure should be performed.

RESUMO Objetivo Apresentar a correlação entre o Thyroid Imaging Reporting and Data System (TI-RADS) e o sistema Bethesda, para relatar citopatologia em 1.000 nódulos tireoidianos. Métodos Estudo retrospectivo realizado no período de novembro de 2011 a fevereiro de 2014, que avaliou 1.000 nódulos tireoidianos de 906 pacientes submetidos a exame de ultrassonografia e à punção aspirativa por agulha fina. Resultados Observou-se associação significativa entre o TI-RADS e o resultado da classificação de Bethesda (p<0,001). A maioria dos indivíduos com TI-RADS 2 ou 3 teve resultado citológico Bethesda 2 (95,5% e 92,5%, respectivamente). Entre aqueles classificados TI-RADS 4C e 5, a maioria teve resultado Bethesda 6 (68,2% e 91,3%, respectivamente; p<0,001). A proporção de malignidades em TI-RADS 2 foi 0,8% e em TI-RADS 3 foi 1,7%. Entre TI-RADS 4A, foi de 16,0%, 43,2% em 4B, 72,7% em 4C e em 5 foi de 91,3% (p<0,001), mostrando clara associação entre o TI-RADS e os resultados da biópsia. Conclusão O TI-RADS é apropriado para avaliar nódulos da tireoide e evitar punção aspirativa por agulha fina desnecessária, além de auxiliar na decisão sobre quando este procedimento deve ser realizado.

Differentiation between Benign and Malignant Solid Thyroid Nodules Using an US Classification System

OBJECTIVE: To evaluate the diagnostic accuracy of a new ultrasound (US) classification system for differentiating between benign and malignant solid thyroid nodules. MATERIALS AND METHODS: In this study, we enrolled 191 consecutive patients who received real-time US and subsequent US diagnoses for solid thyroid nodules, and underwent US-guided fine-needle aspiration. Each thyroid nodule was prospectively classified into 1 of 5 diagnostic categories by real-time US: "malignant," "suspicious for malignancy," "borderline," "probably benign," and "benign". We evaluated the diagnostic accuracy of thyroid US and the cut-off US criteria by comparing the US diagnoses of thyroid nodules with cytopathologic results. RESULTS: Of the 191 solid nodules, 103 were subjected to thyroid surgery. US categories for these 191 nodules were malignant (n = 52), suspicious for malignancy (n = 16), borderline (n = 23), probably benign (n = 18), and benign (n = 82). A receiver-operating characteristic curve analysis revealed that the US diagnosis for solid thyroid nodules using the 5-category US classification system was very good. The sensitivity, specificity, positive and negative predictive values, and accuracy of US diagnosis were 86%, 95%, 91%, 92%, and 92%, respectively, when benign, probably benign, and borderline categories were collectively classified as benign (negative). CONCLUSION: The diagnostic accuracy of thyroid US for solid thyroid nodules is high when the above-mentioned US classification system is applied.

Comparação das classificações dos nódulos de tireoide ao Doppler colorido descritas por Lagalla e Chammas / Comparison of color Doppler-evaluated thyroid nodule classifications as described by Lagalla and Chammas

OBJETIVO: Avaliar as classificações da vascularização dos nódulos de tireoide ao Doppler colorido descritas por Lagalla e cols. e Chammas e cols. MÉTODOS: Foram estudados 265 nódulos de tireoide com Doppler colorido e citopatologia. RESULTADOS: No diagnóstico de nódulos com citopatologia maligna, os padrões IV e V de Chammas mostraram sensibilidade de 16,7 por cento, especificidade de 97,6 por cento, valor preditivo positivo de 33,3 por cento, valor preditivo negativo de 94,1 por cento e acurácia de 92,1 por cento. O padrão III de Lagalla mostrou sensibilidade de 44,4 por cento, especificidade de 19,4 por cento, valor preditivo positivo de 3,9 por cento, valor preditivo negativo de 82,8 por cento e acurácia de 21,1 por cento. CONCLUSÃO: A classificação de Lagalla mostrou baixas sensibilidade e acurácia na detecção de nódulos com citopatologia maligna, enquanto a classificação de Chammas mostrou alta acurácia, porém baixa sensibilidade. O Doppler colorido mostrou-se insuficiente para substituir a punção com agulha fina e o estudo citopatológico no diagnóstico dos nódulos malignos da tireoide.

ABSTRACTOBJECTIVE: Evaluate the vascularization classification of thyroid nodules with color Doppler ultrasonography described by Lagalla and cols. and Chammas and cols. METHODS: A total of 265 thyroid nodules were studied with color Doppler and citopathology. RESULTS: In the diagnosis of nodules with malignant citopathology, Chammas's IV and V patterns showed sensibility of 16.7 percent, specificity of 97.6 percent, positive predictive value of 33.3 percent, negative predictive value of 94.1 percent and accuracy of 92.1 percent; Lagalla's III pattern showed sensibility of 44.4 percent, specificity of 19.4 percent, positive predictive value of 3.9 percent, negative predictive value of 82.8 percent and accuracy of 21.1 percent. CONCLUSION: Lagalla's classification showed low sensibility and accuracy in the detection of nodules with malignant citopathology, while Chammas's classification showed high accuracy, however, low sensibility. Color Doppler was also insufficient to substitute the small needle punction and the citopathologic study in the diagnosis of malignant thyroid nodules.

Classificação ultra-sonográfica dos nódulos tireóideos segundo o risco de malignidade / Ultrasonographic classification of thyroid nodules according the risk of malignancy

A ultra-sonografia da tireóide, por ser um método simples, não invasivo e apresentar boa correlação com os aspectos macroscópicos dos nódulos tireóideos é um procedimento cada vez mais empregado na avaliação inicial da lesão nodular da tireóide. Nenhum sinal ultra-sonográfico é patognomônico para nódulo maligno mas a associação de algumas características como ausência de halo, presença de microcalcificações, hipoecogenicidade e contornos irregulares, aumenta o risco de malignidade de uma lesão. Dessa forma, o ultra-som pode identificar as lesões nodulares com maior potencial de malignidade, permitindo selecionar nódulos para biópsias em uma tireóide multinodular / Thyroid ultrasound is widely used as the initial work-up in patients with thyroid nodules. This imaging method is easy, noninvasive and very sensitive for detecting subtle variations in thyroid nodule architecture. However, there has been no reliable sonographic signs for distinguishing benign from malignant thyroid conditions. In the case that multiple ultrasonographic abnormalities are simultaneously present in a thyroid nodule, such as absence or an incomplete peripheral halo, internal microcalcifications, hypoechoic pattern and irregular margin, this echographic appeareance may favour the diagnosis of malignancy...

Evaluación de nódulos tiroídeos mediante punción aspirativa con aguja fina bajo ultrasonido: experiencia en 120 casos / Evaluation of thyroid nodules using ultrasound guided fine needle aspiration biopsy: experience in 120 cases

Los nódulos tiroideos son un problema clínico común, su prevalencia es de un 4 a 7 por ciento. La mayoría son benignos, pero alrededor de un 0,1 a 20 por ciento son malignos. La PAAF guíada por ultrasonido nos permite seleccionar aquellos nódulos que requieren cirugía con un alto grado de sensibilidad y especificidad evitando procedimientos innecesarios y costosos. El propósito del estudio es establecer la eficacia del método, determinando la incidencia de cáncer en la población estudiada y los parámetros técnicos mas adecuados que permitan una punción óptima

Solitary thyroid nodule: a study of 100 cases.

One hundred cases of solitary thyroid nodules attending the thyroid clinic, Institute of Postgraduate Medicine & Research, Dhaka (IPGMR) and the Institute of Nuclear Medicine (INM) were included in a prospective study. Thyroid ultrasonography (USG), scintiscanning, radioactive iodine (I131) uptake (RAIU), estimation of serum total T3, T4 & TSH and Fine Needle Aspiration Cytology (FNAC) were performed in all cases. Surgical resection with histopathologic study was performed in selected cases. Extra-nodular part of the thyroid gland was normal in 68 and diffusely enlarged in 32, RAIU was normal in 62, high in 36 and very low in two subjects. Nodules were solid at USG in 67 subjects, cystic in 16 subjects and of mixed consistency in 17 subjects. Goitrous subjects had significantly lower T4 (p < 0.001) and higher T3 (p < 0.01) and TSH (p < 0.001) than non-goitrous ones. Colloid nodule was the commonest pathology occurring in 41 cases, followed by thyroid cysts (26), follicular adenoma (23), adenoma with cystic change (7), subacute thyroiditis (2) and papillary carcinoma (1). Colloid nodules were more common in goitrous subjects which could hint at iodine deficiency as the major cause of such nodules. Hyperfunctioning follicular adenomas occurred exclusively in non-goitrous subjects. Carcinoma appeared to be uncommon in patients with solitary nodules. It gives an opportunity to our physicians to be more conservative in selecting patients with solitary thyroid nodules for surgical treatment.

Punción de nódulos tiroídeos con aguja fina: análisis de los resultados obtenidos utilizando una nueva metódica con examen histológico de la muestra / Fine needle punction of thyroid nodules: analysis of obtained results using a new method with histological test of the sample

Fine needle aspiration biopsy (FNAB) is the most usuful preoperative work up method for patients with nodular goiter. We analyze 173 patients that underwent FNAB and were subsequently operated. The sample obtained with FNAB was processed both for cytological and histological study, using methods developed at the hospital. The preoperative diagnosis reached was compared with that obtained with the surgical piece. Results showed that the the histological analysis of the FNAB sample improved the sensitivity of the method, when compared with the cytological study, from 68,5 percent to 87.8 percent (p<0,035) without modifying specificity (100 percent for both methods). It is concluded that FNAB with histological study of the sample has a high diagnostic yield and is exempt of complications