Incidência e mortalidade por câncer de tireóide no Brasil

Ultrasound classification of thyroid nodules: does size matter?

Objective

To determine whether the size of thyroid nodules in ACR-TIRADS ultrasound categories 3 and 4 is correlated with the Bethesda cytopathology classification.

Methods

Thyroid nodules (566) subclassified as ACR-TIRADS 3 or 4 were divided into three size categories according to American Thyroid Association guidelines. The frequency of different Bethesda categories in each size range within ACR-TIRADS 3 and 4 classifications was analyzed.

Results

Most nodules in both ACR-TIRADS classifications fell in the Bethesda 2 category, regardless of size (90.8% and 68.6%, ACR-TIRADS 3 and 4 respectively). The prevalence of Bethesda 6 nodules in the ACR-TIRADS 4 group was 14 times higher than in the ACR-TIRADS 3 group. There were no significant differences between nodule size and fine needle aspiration biopsy classification in any of the ACR-TIRADS categories.

Conclusion

Size does not appear to be an important criterion for indication of fine needle aspiration biopsy in thyroid nodules with a high suspicion of malignancy on ultrasound examination.

Thyroid nodules ≤ 1 cm and papillary thyroid microcarcinomas: Brazilian experts opinion

The indolent evolution of low-risk papillary thyroid microcarcinoma (mPTC) in adult patients and the consequences of thyroidectomy require a revision of the management traditionally recommended. Aiming to spare patients unnecessary procedures and therapies and to optimize the health system in Brazil, we suggest some measures. Fine-needle aspiration of nodules ≤ 1 cm without extrathyroidal extension on ultrasonography should be performed only in nodules classified as "very suspicious" (i.e., high suspicion according to ATA, high risk according to AACE, TI-RADS 5) and in selected cases [age < 40 years, nodule adjacent to the trachea or recurrent laryngeal nerve (RLN), multiple suspicious nodules, presence of hypercalcitoninemia or suspicious lymph nodes]. Active surveillance (AS) rather than immediate surgery should be considered in adult patients with low-risk mPTC. Lobectomy is the best option in patients with unifocal low-risk mPTC who are not candidates for AS because of age, proximity of the tumor to the trachea or RLN, or because they opted for surgery. The same applies to patients who started AS but had a subsequent surgical indication not due to a suspicion of tumor extension beyond the gland or multicentricity. Molecular tests are not necessary to choose between AS and surgery or, in the latter case, between lobectomy and total thyroidectomy. The presence of RAS or other RAS-like mutations or BRAFV600E or other BRAF V600E-like mutations should not modify the management cited above; however, the rare cases of mPTC exhibiting high-risk mutations, like in the TERT promoter or p53, are not candidates for AS.

Does the Bethesda category predict aggressive features in differentiated thyroid cancer?

OBJECTIVE

To analyze the importance of preoperative cytology of thyroid nodules and its relationship with mortality risk, recurrence risk, dynamic stratification, and aggressive characteristics (vascular invasion, aggressive histology, incomplete tumor resection, extrathyroidal extension of the tumor, and presence of lymph node and distant metastases).

SUBJECTS AND METHODS

Retrospective evaluation of 153 patients diagnosed with differentiated thyroid carcinoma (DTC) and following up at the Hospital Universitário Presidente Dutra between January 1999 and December 2016.

RESULTS

In all, 96% of the patients were female, 79.7% had papillary carcinoma and the most common fine-needle aspiration (FNA) result was Bethesda II (29.4%). The mean age was 43.11 ± 12.8 years. Overall, 85% of the patients progressed without any evidence of disease. There was a statistically significant relationship between the presurgical FNA and the presence of extrathyroidal extension, vascular invasion, and lymph node metastasis.

CONCLUSIONS

The preoperative cytology of the nodule may have an impact on the follow-up of patients with DTC. Future studies in a larger population are required to confirm this finding.

Thyroid cancer burden and economic impact on the Brazilian public health system

OBJECTIVE

Recent data indicates an increasing incidence of thyroid cancer not accompanied by a proportional increase in mortality, suggesting overdiagnosis, which may represent a big public health problem, particularly where resources are scarce. This article aims to describe and evaluate the procedures related to investigation of thyroid nodules and treatment and follow-up of thyroid cancer and the costs for the Brazilian public health system between 2008 and 2015.

MATERIALS AND METHODS

Data on procedures related to investigation of thyroid nodules and treatment/follow-up of thyroid cancer between 2008 and 2015 in Brazil were collected from the Department of Informatics of the Brazilian Unified Health System (Datasus) website.

RESULTS

A statistically significant increase in the use of procedures related to thyroid nodules investigation and thyroid cancer treatment and follow-up was observed in Brazil, though a reduction was noted for procedures related to the treatment of more aggressive thyroid cancer, such as total thyroidectomy with neck dissection and higher radioiodine activities such as 200 and 250 milicuries (mCi). The procedures related to thyroid nodules investigation costs increased by 91% for thyroid ultrasound (p = 0.0003) and 128% in thyroid nodule biopsy (p < 0.001). Costs related to treatment and follow-up related-procedures increased by 120%.

CONCLUSION

The increase in the incidence of thyroid cancer in Brazil is directly associated with an increased use of diagnostic tools for thyroid nodules, which leads to an upsurge in thyroid cancer treatment and followup-related procedures. These data suggest that substantial resources are being used for diagnosis, treatment and follow-up of a potentially indolent condition.

High Serum Thyrotropin Concentrations within the Reference Range: A Predictor of Malignancy in Nodular Thyroid Disease

OBJECTIVE

This study assessed whether or not a simple biochemical parameter, serum thyrotropin (TSH), within the reference range can predict the likelihood of thyroid malignancy in subjects undergoing fine-needle aspiration biopsy (FNAB) for thyroid nodules.

SUBJECTS AND METHODS

This cross-sectional study evaluated 236 patients without overt thyroid dysfunction who were not on levothyroxine therapy. They underwent FNAB of the thyroid nodules at the Clementino Fraga Filho University Hospital between 2011 and 2012. The reference range and serum TSH quartiles were determined according to age-specific values for serum TSH and then compared between the cases with benign thyroid nodular disease and differentiated thyroid carcinoma (DTC) based on surgical pathology reports.

RESULTS

Of the 236 patients, 201 (85.1%) underwent a surgical procedure (thyroidectomy) and 89/236 (44.3%) had DTC. The mean TSH concentrations were 2.09 ± 1.15 mU/L in benign patients versus 2.73 ± 1.33 mU/L in cases of DTC (p < 0.01). As TSH increased from quartiles 1 to 4, the frequency of a malignant diagnosis also increased progressively from 22% in quartile 1 to 65% in the last quartile (p ≤ 0.001).

CONCLUSION

Thyrotropin levels were positively associated with the diagnosis of DTC in thyroid nodules.

Correlation among ocular surface disease, xerostomia, and nasal symptoms in patients with differentiated thyroid carcinoma subjected to radioiodine therapy: A prospective comparative study

BACKGROUND

Some complications of radioiodine therapy have been reported, but the involvement of the eyes and adnexa is rarely discussed. The purpose of this study was to determine the correlation among ocular surface changes, xerostomia, and changes in the nasal mucosa associated with radioiodine therapy.

METHODS

Patients subjected to radioiodine therapy (group 1) or not subjected (group 2) were prospectively evaluated by examinations of the ocular surface and tear film, saliva production, and nasal endoscopy. Ocular and nasal symptoms and xerostomia were evaluated using questionnaires.

RESULTS

Evaluation of the ocular surface did not indicate significant differences between the groups. Nasal endoscopy revealed higher mucosal pallor in group 1 and worsening of the endoscopic appearance. Worsening of ocular symptoms and nasal symptoms, xerostomia, and a significant decrease in salivary production was also observed in group 1.

CONCLUSION

Subjective worsening of xerostomia, xerophthalmia, nasal symptoms, and changes in the nasal mucosa in group 1 was observed.

Lacrimal System Obstruction After Radioiodine Therapy in Differentiated Thyroid Carcinomas: A Prospective Comparative Study

BACKGROUND

Radioiodine therapy (RIT) is an established treatment for differentiated thyroid carcinomas, and is widely used throughout the world, given the increasing incidence of this malignancy. Although serious adverse effects are infrequent, complications such as dry mouth, sialadenitis, and dysphagia have been described. The involvement of the eyes and accessory visual structures is not commonly discussed, despite dry eye, keratoconjunctivitis, and lacrimal system obstruction (LSO) being reported, especially after high cumulative doses of radiopharmaceuticals. The incidence of LSO is not well established.

OBJECTIVES

The aim of this study was to determine the frequency of LSO in patients undergoing RIT at 2, 4, 6, and 12 months after treatment.

METHODS

Patients with differentiated thyroid carcinoma undergoing (group 1) and not undergoing (group 2) RIT were evaluated in the preoperative and postoperative periods and 2, 4, 6, and 12 months post surgery or post RIT. Patients underwent tear film evaluation and lacrimal system probing and irrigation.

RESULTS

Group 1 (n = 44; 88 eyes) contained three patients (four eyes) with LSO, corresponding to an incidence of 4.55% (four events in 88 eyes) or 6.8% (three cases in 44 patients). Group 2 (n = 43; 86 eyes) did not present any cases of LSO.

CONCLUSIONS

In this study, an active prospective investigation allowed LSO detection during the first six months after RIT. This finding demonstrates the importance of making this association clear to patients and health professionals, with a view to early diagnosis, appropriate treatment, and preventing LSO-related complications.

Can Ultrasound Predict Malignancy in Patient with Thyroid Cold Nodule?

Thyroid nodule is one of the most common endocrine diseases in the world; it occurs in 4–7% of the general population. Depending on the method of discovery, 4–8% nodules are discovered using palpation, 10–41% with ultrasound (US), and 50% through autopsy where only 20% or less of cold thyroid nodules are caused by cancerous lesions. The aim of this study was to assess US as supporting modality for thyroid scintigraphy to predict malignancy in patient with thyroid cold nodules. In a retrospective study between 2009 and 2013, we analyzed 399 subjects with cold thyroid nodule, where 39 subjects (36 women and 3 men) presented with malignant thyroid cold nodule and 19 subjects underwent US. The US showed malignancy parameters in 8 (42.11%) subjects, while the rest of the 11 (57.89%) subject were benign. Out of all the subjects who underwent US in this study, only 8 (42.11%) subjects shown malignancy characteristics in cold thyroid nodule with papillary thyroid cancer (PTC). That means US parameters of malignant thyroid nodule do not always show up in malignant cold thyroid nodule.

Familiar Papillary Thyroid Carcinoma in a Large Brazilian Family Is Not Associated with Succinate Dehydrogenase Defects

BACKGROUND

Thyroid cancer is the most common endocrine gland malignancy. Advances in understanding the genetic basis for thyroid cancer revealed the potential involvement of several genes in the formation of thyroid tumors. Mutations in the gene coding for succinate dehydrogenase subtype B (SDHB) have been implicated in papillary thyroid cancer (PTC). Succinate dehydrogenase (SDH) is a heterotetrameric protein composed of four subunits, SDHA, SDHB, SDHC, and SDHD, and participates in both the electron transport chain and the tricarboxylic acid cycle. The aim of the study was to evaluate the association between variants in the SDHA, SDHB, SDHC, and SDHD genes and familiar PTC in a large Brazilian family.

METHOD

Four patients with PTC, 1 patient with PTC and gastrointestinal stromal tumor (GIST), 1 patient with GIST, and their relatives - several of them with different thyroid problems - from a large Brazilian family were screened for genetic variations of SDHx genes with the use of polymerase chain reaction-single-stranded conformational polymorphism and direct sequencing.

RESULTS

Only one rare variation in SDHA was found in some of the family members, but not segregating with the disease. No other genetic variants of these genes were detected in the family members that presented with PTC and/or GIST.

CONCLUSION

Familiar PTC and a GIST were not associated with SDHx mutations; additional genetic defects, yet unknown, may be responsible for the development of tumor.

Morphometric information to reduce the semantic gap in the characterization of microscopic images of thyroid nodules

BACKGROUND

The analyses of several systems for medical-imaging processing typically support the extraction of image attributes, but do not comprise some information that characterizes images. For example, morphometry can be applied to find new information about the visual content of an image. The extension of information may result in knowledge. Subsequently, results of mappings can be applied to recognize exam patterns, thus improving the accuracy of image retrieval and allowing a better interpretation of exam results. Although successfully applied in breast lesion images, the morphometric approach is still poorly explored in thyroid lesions due to the high subjectivity thyroid examinations.

OBJECTIVE

This paper presents a theoretical-practical study, considering Computer Aided Diagnosis (CAD) and Morphometry, to reduce the semantic discontinuity between medical image features and human interpretation of image content.

METHOD

The proposed method aggregates the content of microscopic images characterized by morphometric information and other image attributes extracted by traditional object extraction algorithms. This method carries out segmentation, feature extraction, image labeling and classification. Morphometric analysis was included as an object extraction method in order to verify the improvement of its accuracy for automatic classification of microscopic images.

RESULTS

To validate this proposal and verify the utility of morphometric information to characterize thyroid images, a CAD system was created to classify real thyroid image-exams into Papillary Cancer, Goiter and Non-Cancer. Results showed that morphometric information can improve the accuracy and precision of image retrieval and the interpretation of results in computer-aided diagnosis. For example, in the scenario where all the extractors are combined with the morphometric information, the CAD system had its best performance (70% of precision in Papillary cases).

CONCLUSION

Results signalized a positive use of morphometric information from images to reduce semantic discontinuity between human interpretation and image characterization.

Estabilidad de la mortalidad por cáncer de tiroides en un país emergente

<p><strong>Objetivo</strong> Establecer características y tendencia de la mortalidad por cáncer de tiroides en Colombia.</p><p><strong>Materiales y Métodos</strong> Estudio de la mortalidad por cáncer de tiroides empleando las bases oficiales nacionales de muertes en Colombia (1998-2010). Se analizaron año de defunción, sexo, edad y departamento de residencia. Se utilizaron proporciones, media aritmética y mediana. El valor de <em>p</em> límite para significación estadística fue 0,05. Se calcularon tasas crudas, específicas y ajustadas por edad.</p><p><strong>Resultados</strong> En total, 2 570 personas, 1 827 (71,1 %) muertes ocurrieron en mujeres. Las edades medianas a la muerte fueron de 68 años en hombres y de 70 años en mujeres. La tasa anual media de mortalidad por cáncer de tiroides ajustada (2006-2010) fue de 0,52 muertes por 100 000 personas (ambos sexos), 0,32 muertes por 100 000 hombres y 0,70 por 100 000 mujeres.</p><p><strong>Conclusiones</strong> Deben realizarse estudios que muestren posibles factores asociados a muerte a más temprana edad en mujeres colombianas.</p><p> </p>

Analysis of pattern of occurrence of thyroid carcinoma between 2001 and 2010

INTRODUCTION

An ongoing discussion is found in medical literature about the reasons for changes in thyroid carcinoma incidence patterns over the last decades.

OBJECTIVE

To analyze the clinical and pathological characteristics of thyroid carcinoma cases over a decade.

METHODS

Cross-sectional study over an historical cohort. Medical records of 628 thyroid cancer cases in a single center were reviewed. 597 patients were included. Microcarcinoma cases were selected for a qualitative analysis phase, in which medical records were reviewed for better understanding of thyroid nodule and thyroid cancer diagnosis process.

RESULTS

An increase in the proportion of cases with thyroid cancer diagnosis was observed throughout the decade; new cases were predominantly tumors of less than 2 cm, with histopathological signs of low aggressiveness. There was an increase in proportion of cases with malignant cytological results among microcarcinomas.

CONCLUSION

There is a trend for increase in thyroidectomies due to cancer in this institution, with proportional increment of cases with histopathological characteristics indicative of early disease. Among microcarcinomas, there is an increasing group represented by cancer cases that were not incidentally diagnosed, related to an enhancement in preoperative diagnostic methods.

Evolution in the profile of thyroid cancer cases treated in an oncology reference service: what changed in the last 20 years

Objective: To evaluate the characteristics of thyroid carcinoma cases treated at a reference hospital for cancer between 2008 and 2010.Methods: we studied 807 cases and analyzed the following clinicopathologic variables: symptoms, risk factors, diagnostic tests, staging, histological type, treatment performed and complications.Results: Females were more affected, with 660 cases (82%). The average age at diagnosis was 44.5 years. Prior exposure to ionizing radiation was reported by 22 (3%) patients, a family history of thyroid cancer by 89 (11%), and 289 (36%) individuals reported other types of cancer in the family. The fine needle aspiration biopsy was the main parameter for surgical indication and was suggestive of carcinoma in 463 patients (57%). Papillary carcinoma was the most common histological type, with 780 cases (96.6%). There were 728 (90%) total thyroidectomies, 43 (5.3%) reoperations or partial thyroidectomies followed by totalization, 23 (2.8%) extended thyroidectomies and only 13 (1.6%) partial thyroidectomies (lobectomy with isthmectomy). Neck dissection associated with thyroidectomy was done in 158 patients (19.5%). We observed a predominance of tumors classified as T1 in 602 (74.6%) patients. Transient hypocalcemia was the most frequent complication.Conclusion: The results show that the worldwide increase in the incidence of thyroid cancer has changed the profile of patients seen at a referral service. In addition, there were changes in the type of surgical treatment used, with increased use of total thyroidectomy in relation to partial and subtotal ones, and decreased use of elective neck dissections.

Prevalence of thyroid diseases in patients with acromegaly: experience of a Brazilian center

OBJECTIVES: Acromegaly is frequently associated with thyroid diseases. In this study, we evaluated the frequency of thyroid disorders in a series of acromegalic patients. SUBJECTS AND METHODS: We evaluated 106 acromegalic patients using thyroid ultrasonography (US) and measurements of GH, IGF-I, free T4, TSH and anti-thyroperoxidase antibody levels. IGF-I was expressed in mass units and age-related standard deviation scores (SD-scores). Fine-needle aspiration biopsy (FNAB) was performed on thyroid nodules with a diameter greater than one centimeter or with suspicious characteristics. RESULTS: Thyroid disorders were found in 75 patients. Eleven patients had diffuse goiter, 42 patients had nodular goiter, and 22 patients had unspecific morphological abnormalities. Four patients (3.8%) had thyroid carcinoma. Considering the patients with diffuse or nodular goiter, thyroid volume was greater in patients with active acromegaly, and was positively correlated with GH, IGF-I, and IGF-I SD-score. CONCLUSIONS: Our study confirmed that benign thyroid diseases are frequent in acromegalic patients. The prevalence of thyroid cancer was higher than in the overall population. We suggest that thyroid US should be routinely performed in patients with acromegaly.

Thyroid papillary carcinoma associated to Hashimoto's thyroiditis

There is controversy in the literature regarding the association between papillary thyroid carcinoma (PTC) and Hashimoto's thyroiditis (HT) and as to what would be the etiological relationship between them.

Objective

To establish the proportion of cases among patients with TH and CPT, correlating it with histomorphological aspects.

Method

A retrospective study of patients undergoing partial or total thyroidectomy for PTC between 2007 and 2009, a total of 41 cases.

Results

Regarding the association of HT and CPT, we found 11 cases (26.8%), all females, but without statistical significance. The mean age was 44.9 years among the patients with coexistent TH and CPT, whereas it was 49.1 years without that association. The average size of tumors in those without TH was 20.53 mm and for those with TH it was 12.72 mm (p = 0.4). Regarding pathology staging, the ratiosbetween those with and those without TH were kept in T1a, T1b and T3. In T2, there were no cases of coexistence of HT and PTC.

Conclusion

There is a rate of 26.8% of patients with association between TH and CPT, but without differences in relation to tumor size.

Thyroid cancer in patients with acromegaly: a case-control study

Several studies have associated acromegaly with an increased risk of benign and malignant tumors. While simple and multinodular goiters are common findings in acromegaly, the prevalence of thyroid cancer is uncertain. The objective of this study was to estimate the prevalence of thyroid cancer in a series of acromegalic patients from three hospitals in northeast of Brazil. The methodology used included morphological, cytological and histological thyroid analysis of acromegalic patients and volunteers over 18 years, matched for age and sex and with nodule (s) ≥1 cm. The subjects of this study were 124 acromegalic patients, including 76 females (61.3%) and 48 men (38.7%), with a mean age 45.1 years. Results of the study showed that thyroid ultrasonography was normal in 31 cases (25%), 25 had diffuse goiter (20.1%), 67 had nodules (54%) and one agenesis of the right lobe (0.8%). Thirty-six patients underwent fine needle aspiration biopsy (FNAB) of their nodules and 9 cases of papillary cancer were found (7.2%). The control group consisted of 263 subjects, 156 females (59.3%) and 107 males (40.7%), mean age 44.7 years. In ultrasound assessment, 96 had nodules (36.5%). Of these, 13 were punctured and 2 cases of papillary carcinoma were found (0.7%). These results gave an odds ratio of 10.21 (p = 0.0011, 95% CI 2.17 to 48.01). These findings demonstrate an increased prevalence of thyroid cancer, statistically significant when compared to our control group. Thus, it is suggested that acromegalic patients should be routinely submitted to thyroid ultrasound evaluation, followed by FNAB of nodules when indicated.

Thyroid nodule management: clinical, ultrasound and cytopathological parameters for predicting malignancy

Although fine-needle aspiration cytology is considered to be the reference method for evaluating thyroid nodules, the results are inaccurate in approximately 10-30% of cases. Several studies have attempted to predict the risk of malignancy in thyroid nodules based on age, nodularity, thyrotropin values, thyroid autoimmune disease, hot/cold nodule status, and ultrasound parameters. However, no consensus has been found, and none of these parameters has significantly affected patient management. The management of indeterminate thyroid nodules and re-biopsies of nodules with initially benign cytological results remain important and controversial topics of discussion. The Bethesda cytological system and several studies on the use of molecular markers to predict malignancy from cytological samples of thyroid nodules need further clarification. More in-depth discussions among and continuous education of the specialists involved in treating thyroid disease are necessary to improve the management of these patients. This review aims to examine the clinical, laboratory, ultrasound, and scintigraphic parameters that can be used for thyroid nodule management.

Estimates of thyroid cancer incidence in Brazil: an approach using polynomial models

This study aimed to estimate thyroid cancer incidence in Brazil in 2006 using polynomial models that take age and birth cohort effects into account in the estimation process. Estimates were based on new cases of thyroid cancer in nine Brazilian cities (Manaus, Palmas, Natal, Recife, Cuiabá, Belo Horizonte, São Paulo, Porto Alegre, and Curitiba) and the Federal District from 1997 to 2001. We estimated 6,066 new cases, of which 1,065 in men and 5,001 in women. The incidence rates were, respectively, 1.16 and 5.27 per 100,000 inhabitants. Rates increased with age in both genders, especially after 30 years. The size and profile of rates according to age and gender indicate that the method yields plausible estimates.

Value of ultrasound and cytological classification system to predict the malignancy of thyroid nodules with indeterminate cytology

Although fine-needle aspiration cytology is considered the gold standard for evaluating thyroid nodules, in about 10-30% of the cases, cytology is indeterminate. This study aimed to determine the value of cytological classification system and ultrasound (US) to predict malignancy in indeterminate thyroid nodule. This retrospective analysis enrolled 80 patients surgically treated at a single center, 75% (60) with benign vs. 25% (20) with malignant lesions at final histology. The clinical, scintigraphic, sonographic, and cytological classification (Bethesda) variables were analyzed in these selected cases of indeterminate cytology, and a prediction model was designed after the multivariate analysis. There was a 25% prevalence of malignancy (20/80). There were no differences in gender, serum thyroid-stimulating hormone and FT4 levels, thyroid auto-antibodies, thyroid dysfunction, and scintigraphic results between benign and malignant nodule groups. The border irregularity in sonographic study was at increased risk for malignancy. The cytological analysis based on Bethesda System (category IV) was an independent predictor for malignancy in indeterminate thyroid nodules. After the multivariate analysis, the model obtained showed border irregularity and Bethesda System category IV as predictive factors of malignancy in indeterminate thyroid nodules, featuring 76.9% of accuracy. This study confirmed a significant increase of risk for malignancy in thyroid nodules with indeterminate cytology showing Bethesda System category IV and suspicious features at US. These findings enhance our current limited predictive armamentarium and can be used to guide surgical decision making.

FN1, GALE, MET, and QPCT overexpression in papillary thyroid carcinoma: molecular analysis using frozen tissue and routine fine-needle aspiration biopsy samples

Thyroid nodules are a common clinical problem, and fine-needle aspiration biopsy (FNAB) is widely used for its evaluation. Only 5% are malignant, being papillary carcinoma (PC) the most frequent neoplasia. Approximately 20% are classified as indeterminate or suspicious for malignancy. Gene-expression pattern may be useful for diagnosing PC in difficult or ambiguous cases. In our prior study, we were able to apply RT-PCR method in a series of routinely performed FNAB of thyroid nodules using individual, residual samples. In this study, a total of 70 thyroid samples were evaluated for the expression of MPPED2, H/HBA2, MET, FN1, GALE, and QPCT genes, including 24 cases of frozen thyroid tissue, 12 nodular hyperplasia and 12 PC, and the 46 consecutive thyroid FNAB samples, previously analyzed (3 positive, 10 indeterminate and 32 negative for malignancy, and 1 insufficient). FN1, GALE, MET, and QPCT mRNA expression were significantly different in benign and malignant samples, with similar pattern of overexpression in aspirates compared to frozen tissue. H/HBA2 and MPPED2 expression varied. Histological correlation was possible in five indeterminate cases, revealing one PC and four benign lesions. In conclusion, FN1, GALE, MET, and QPCT were significantly overexpressed in thyroid PC. RT-PCR method could be applied to routine FNAB, showing a similar pattern of overexpression. Despite the small number of cases evaluated, our results suggest that molecular analysis may be of assistance in patients with indeterminate/suspicious cytology, adding elements for preoperative diagnosis and better management of these patients.

Absence of Peritumoral Fibrosis or Inflammatory Infiltrate May Be Related to Clinical Progression of Papillary Thyroid Microcarcinoma

Rio Grande do Norte (RN) shows the highest relative incidence of papillary carcinomas in Brazil. To analyze histological features that might be associated with this incidence, the authors compared thyroid glands from 463 autopsies performed in RN with 427 surgical and autopsy glands previously studied in Sao Paulo (SP). The authors found 41 papillary thyroid microcarcinomas (PTMs) in 35 glands (8.1%), an incidence similar to the one reported in SP (7.8%). However, PTMs were predominantly nonencapsulated nonsclerosing at microscopy (44.0%), in contrast with SP where these types of lesion represented only 4 out of 32 PTMs (12.5%; P = .0046). The authors suggest that these nonencapsulated lesions with no sign of inflammation may represent an early stage that may evolve to clinical cancers, contributing to the high incidence of clinically differentiated thyroid carcinomas observed in RN.