Not Only RET but NF1 and Chromosomal Instability Are Seen in Young Patients with Sporadic Medullary Thyroid Carcinoma.

Context: Genetic analysis of sporadic medullary thyroid carcinoma (MTC) has revealed somatic variants in RET, RAS, and occasionally other genes. However, around 20% of patients with sporadic MTC lack a known genetic driver. Objective: To uncover potential new somatic or germline drivers, we analyze a distinct cohort of patients with sporadic, very early-onset, and aggressive MTC. Methods: Germline and somatic DNA exome sequencing was performed in 19 patients, previously tested negative for germline RET variants. Results: Exome sequencing of 19 germline samples confirmed the absence of RET and identified an NF1 pathogenic variant in 1 patient. Somatic sequencing was successful in 15 tumors revealing RET variants in 80%, predominantly p.Met918Thr, which was associated with disease aggressiveness. In RET-negative tumors, pathogenic variants were found in HRAS and NF1. The NF1 germline and somatic variants were observed in a patient without a prior clinical diagnosis of neurofibromatosis type 1, demonstrating that the loss of heterozygosity of NF1 functions as a potential MTC driver. Somatic copy number alterations analysis revealed chromosomal alterations in 53.3% of tumors, predominantly in RET-positive cases, with losses in chromosomes 9 and 22 being the most prevalent. Conclusion: This study reveals that within a cohort of early-onset nonhereditary MTC, RET remains the major driver gene. In RET-negative tumors, NF1 and RAS are drivers of sporadic MTC. In addition, in young patients without a RET germline mutation, a careful clinical evaluation with a consideration of germline NF1 gene analysis is ideal to exclude Neurofibromatosis type 1 (NF1).

Prevalence of DICER1 variants in large multinodular goiter: thyroid function, clinical and imaging characteristics.

Objective: Mutations in DICER1 are found in differentiated thyroid carcinoma (DTC) and in multinodular goiter (MNG) at a younger age with other tumors, which characterizes DICER1 syndrome. DICER1 is one driver to DTC; however, it is also found in benign nodules. We speculated that patients with mutations in DICER1 may present long-lasting MNG. Our aim was to investigate the frequency of DICER1 variants in patients with MNG. Subjects and methods: Patients who submitted to total thyroidectomy due to large MNG with symptoms were evaluated. DICER1 hotspots were sequenced from thyroid nodule samples. To confirm somatic mutation, DNA from peripheral blood was also analyzed. Results: Among 715 patients, 154 were evaluated with 56.2 ± 12.3 years old (28-79) and the thyroid volume was 115.7 ± 108 mL (16.2-730). We found 11% with six DICER1 variations in a homo or heterozygous state. Only rs12018992 was a somatic DICER1 variant. All remaining variants were synonymous and likely benign, according to the ClinVar database. The rs12018992 was previously described in an adolescent with DTC, measuring 13 mm. There were no significant differences according to gender, familial history of goiter, age, thyroid volume, TSH and TI-RADS classification between DICER1 carriers. Free T4 were lower in patients with DICER1 polymorphisms (13.77 ± 1.8 vs. 15.44 ± 2.4 pmol/L, p = 0.008), regardless of TSH levels. Conclusion: We conclude that germline DICER1 variants can be found in 11% of large goiters but no second-hit somatic mutation was found. DICER1 is one driver to thyroid lesion and a second-hit event seems unnecessary in the MNG development.

Prevalence of DICER1 variants in large multinodular goiter: thyroid function, clinical and imaging characteristics

ABSTRACT Objective: Mutations in DICER1 are found in differentiated thyroid carcinoma (DTC) and in multinodular goiter (MNG) at a younger age with other tumors, which characterizes DICER1 syndrome. DICER1 is one driver to DTC; however, it is also found in benign nodules. We speculated that patients with mutations in DICER1 may present long-lasting MNG. Our aim was to investigate the frequency of DICER1 variants in patients with MNG. Subjects and methods: Patients who submitted to total thyroidectomy due to large MNG with symptoms were evaluated. DICER1 hotspots were sequenced from thyroid nodule samples. To confirm somatic mutation, DNA from peripheral blood was also analyzed. Results: Among 715 patients, 154 were evaluated with 56.2 ± 12.3 years old (28-79) and the thyroid volume was 115.7 ± 108 mL (16.2-730). We found 11% with six DICER1 variations in a homo or heterozygous state. Only rs12018992 was a somatic DICER1 variant. All remaining variants were synonymous and likely benign, according to the ClinVar database. The rs12018992 was previously described in an adolescent with DTC, measuring 13 mm. There were no significant differences according to gender, familial history of goiter, age, thyroid volume, TSH and TI-RADS classification between DICER1 carriers. Free T4 were lower in patients with DICER1 polymorphisms (13.77 ± 1.8 vs. 15.44 ± 2.4 pmol/L, p = 0.008), regardless of TSH levels. Conclusions: We conclude that germline DICER1 variants can be found in 11% of large goiters but no second-hit somatic mutation was found. DICER1 is one driver to thyroid lesion and a second-hit event seems unnecessary in the MNG development.

Risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy in thyroid nodules with diameters greater than 4 centimeters.

Objective: The risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy (FNAB) of thyroid nodules (TN) with diameters ≥ 3-4 cm remains controversial. However, some groups have indicated surgical treatment in these patients regardless of the FNAB results. We aimed to evaluate the diagnostic accuracy of the FNAB in systematically resected ≥4 cm TN and if the risk of malignancy is higher in these patients. Subjects and methods: We retrospectively evaluated 138 patients (142 nodules) with TN with diameters ≥4 cm who underwent thyroidectomy. Results: The FNAB results were nondiagnostic/unsatisfactory (ND/UNS) in 2.1% of the cases and benign in 51.4%. They indicated atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) in 23.9% of cases, follicular neoplasia/suspicious for a follicular neoplasm (FN/SFN) in 9.2%, suspicion of malignancy (SUS) in 8.5%, and malignant in 4.9%. The histopathological analysis after thyroidectomy revealed a thyroid cancer rate of 100% in the FNABs classified as malignant, 33.3% in SUS cases, 7.7% in FN/SFN, 17.6% in AUS/FLUS, and 4.1% in benign FNABs. None of the ND/UNS FNABs were malignant. The global malignancy diagnosis was 14.8% (n = 21). However, the rate of false negatives for FNAB was low (4.1%). Conclusion: We showed that the risk of malignancy in nodules with diameters ≥4 cm was higher compared to the risk of thyroid cancer in TN in general. However, we found a low rate of false-negative cytological results; therefore, our data do not justify the orientation of routine resection for these larger nodules.

Risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy in thyroid nodules with diameters greater than 4 centimeters

ABSTRACT Objective: The risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy (FNAB) of thyroid nodules (TN) with diameters ≥ 3-4 cm remains controversial. However, some groups have indicated surgical treatment in these patients regardless of the FNAB results. We aimed to evaluate the diagnostic accuracy of the FNAB in systematically resected ≥4 cm TN and if the risk of malignancy is higher in these patients. Subjects and methods: We retrospectively evaluated 138 patients (142 nodules) with TN with diameters ≥4 cm who underwent thyroidectomy. Results: The FNAB results were nondiagnostic/unsatisfactory (ND/UNS) in 2.1% of the cases and benign in 51.4%. They indicated atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) in 23.9% of cases, follicular neoplasia/suspicious for a follicular neoplasm (FN/SFN) in 9.2%, suspicion of malignancy (SUS) in 8.5%, and malignant in 4.9%. The histopathological analysis after thyroidectomy revealed a thyroid cancer rate of 100% in the FNABs classified as malignant, 33.3% in SUS cases, 7.7% in FN/SFN, 17.6% in AUS/FLUS, and 4.1% in benign FNABs. None of the ND/UNS FNABs were malignant. The global malignancy diagnosis was 14.8% (n = 21). However, the rate of false negatives for FNAB was low (4.1%). Conclusion: We showed that the risk of malignancy in nodules with diameters ≥4 cm was higher compared to the risk of thyroid cancer in TN in general. However, we found a low rate of false-negative cytological results; therefore, our data do not justify the orientation of routine resection for these larger nodules.

Active Surveillance of Thyroid Microcarcinomas: a Critical View.

PURPOSE OF THE REVIEW: There has been an increasing interest on active surveillance for papillary thyroid microcarcinomas (PTMC) in the literature. We will analyze the contributions of those authors who support this approach in most patients with low-risk tumors. RECENT FINDINGS: The development of molecular methods to effectively detect aggressive PTMC at the fine-needle aspiration biopsy will enable the sound indication of immediate surgery in those patients, assuring the other individuals with the far more frequent indolent PTMC will undergo active surveillance with less anxiety. Several studies compared the quality of life between patients with PTMC who underwent active surveillance with immediate total thyroidectomy. However, thyroid lobectomy is a quite acceptable intermediate alternative for most patients with PTMC, with less surgical morbidity. It is important to wait for worldwide validation, with reports from low- and middle-income areas, before recommending the routine adoption of active surveillance for patients with PTMC, due to difficult logistic obstacles in those environments.

Multiparametric Ultrasound Evaluation of the Thyroid: Elastography as a Key Tool in the Risk Prediction of Undetermined Nodules (Bethesda III and IV)-Histopathological Correlation.

The purpose of this study was to select thyroid nodules most at risk for malignancy among those cytologically undetermined by fine-needle aspiration biopsy (FNAB), using B-mode, color duplex Doppler and 2-D shear wave shear wave elastography (2-D-SWE). This was a prospective diagnostic accuracy study with 62 Bethesda III/IV nodules according to FNAB (atypia/follicular lesion of undetermined significance or follicular neoplasia/Hürthle cell neoplasm). Ultrasonography (US) data were compared with resection histologic results, revealing 35 of 62 benign nodules (56.4%) and 27 of 62 carcinomas (43.6%). Conventional US was uses to evaluate nodule echogenicity, dimensions, contours, presence of halo and microcalcifications. Doppler US was used to assess the vascularization (exclusively or predominantly peripheral or central) and mean resistance index of three nodule arteries. Elastography was used to evaluate the nodule elastographic pattern; mean nodule deformation index; deformation ratio between nodule and adjacent thyroid parenchyma; and mean deformation ratio between nodule and pre-thyroid musculature (MDR). Statistical analysis included χ2, Fisher's exact, Student's t, Mann-Whitney tests and multivariable analysis by multiple logistic regression. Areas under the receiver operating characteristic curves (AUC-ROCs) were used for accuracy analysis. Fifty-eight participants (54.7 ± 14.0 y, 51 women) were studied. The parameters that were statistically significant to the univariate analysis were hypo-echogenicity, nodule diameter greater than width and all parameters analyzed from Doppler and elastography. Multivariate analysis revealed that the MDR (in kPa) was the best parameter for risk analysis of indeterminate nodules. Nodules with MDRs >1.53 exhibited a greater chance of malignancy (AUC-ROC = 0.98). We conclude that 2-D-SWE is able to select malignant nodules among those cytologically indeterminate, thus avoiding unnecessary surgery in these cytologic groups.

Diagnostic performance of thyroid ultrasound in Hürthle cell carcinomas

ABSTRACT Objective Hürthle cell carcinomas (HCCs) of the thyroid have been recently reclassified as a separate entity due to their distinct clinical and molecular profiles. Few studies have assessed the ability of preoperative characteristics in differentiating HCCs from Hürthle cell adenomas (HCAs) due to the low prevalence of both lesions. This study aimed to compare the preoperative features of HCCs and HCAs and evaluate the diagnostic performance of ultrasound in distinguishing between both. Subjetcs and methods Retrospective study including 101 patients (52 HCCs and 49 HCAs) who underwent thyroid surgery from 2000 to 2016. Clinical, ultrasonographic, and histological data were reviewed. Diagnostic performance of suspicious sonographic features was analyzed in 51 cases (24 HCCs and 27 HCAs). Results Hürthle cell neoplasms were predominant in females. Subjects ≥ 55 years represented 58% of the cases of HCCs and 53% of those of HCAs. Carcinomas were significantly larger (p < 0.001), and a tumor size ≥ 4 cm significantly increased the risk of malignancy (odds ratio 3.67). Other clinical, cytologic, and sonographic data were similar between HCCs and HCAs. Among the HCCs, the lesions were purely solid in 54.2%, hypoechoic in 37.5%, and had coarse calcifications in 12.5%, microcalcifications in 8.3%, irregular contours in 4.2%, and a taller-than-wide shape in 16.7%. Predominantly/exclusive intranodular vascularization was observed in 52.6%. Overall, 58% of the HCCs were classified as TI-RADS 4 or 5 compared with 48% of the HCAs. TI-RADS 4 or 5 had a specificity of only 51.8% and a positive likelihood ratio of 1.21. Conclusions Apart from the lesion size, no other preoperative feature adequately distinguished HCCs from HCAs. Sonographic characteristics raising suspicion for malignancy, which are mostly present in papillary carcinomas, were infrequent in HCCs. New tools must be developed to improve preoperative diagnosis and deferral of surgery in cases of adenomas.

Diagnostic performance of thyroid ultrasound in Hürthle cell carcinomas.

OBJECTIVE: Hürthle cell carcinomas (HCCs) of the thyroid have been recently reclassified as a separate entity due to their distinct clinical and molecular profiles. Few studies have assessed the ability of preoperative characteristics in differentiating HCCs from Hürthle cell adenomas (HCAs) due to the low prevalence of both lesions. This study aimed to compare the preoperative features of HCCs and HCAs and evaluate the diagnostic performance of ultrasound in distinguishing between both. SUBJETCS AND METHODS: Retrospective study including 101 patients (52 HCCs and 49 HCAs) who underwent thyroid surgery from 2000 to 2016. Clinical, ultrasonographic, and histological data were reviewed. Diagnostic performance of suspicious sonographic features was analyzed in 51 cases (24 HCCs and 27 HCAs). RESULTS: Hürthle cell neoplasms were predominant in females. Subjects ≥ 55 years represented 58% of the cases of HCCs and 53% of those of HCAs. Carcinomas were significantly larger (p < 0.001), and a tumor size ≥ 4 cm significantly increased the risk of malignancy (odds ratio 3.67). Other clinical, cytologic, and sonographic data were similar between HCCs and HCAs. Among the HCCs, the lesions were purely solid in 54.2%, hypoechoic in 37.5%, and had coarse calcifications in 12.5%, microcalcifications in 8.3%, irregular contours in 4.2%, and a taller-than-wide shape in 16.7%. Predominantly/exclusive intranodular vascularization was observed in 52.6%. Overall, 58% of the HCCs were classified as TI-RADS 4 or 5 compared with 48% of the HCAs. TI-RADS 4 or 5 had a specificity of only 51.8% and a positive likelihood ratio of 1.21. CONCLUSIONS: Apart from the lesion size, no other preoperative feature adequately distinguished HCCs from HCAs. Sonographic characteristics raising suspicion for malignancy, which are mostly present in papillary carcinomas, were infrequent in HCCs. New tools must be developed to improve preoperative diagnosis and deferral of surgery in cases of adenomas.

Thyroidectomy in children

Introduction: Surgical management of thyroid disease in children presents several peculiarities and has increasingly developed in recent years, but historically few studies conducted with this population have been published. Objective: Analysis of the surgical approach and postoperative outcomes of 59 pediatric patients submitted to thyroidectomy between 2003 and 2019. Methods: An outpatient postoperative follow-up of 59 patients aged 3-18 years submitted to thyroidectomy for different causes was performed, and immediate and late postoperative outcomes were analyzed. The operations were performed at a University Hospital as well as at Private Tertiary Hospitals. Results: The following postoperative outcomes were observed: three tracheostomies, 22 patients with transient hypoparathyroidism, eight patients with definitive hypoparathyroidism, and three patients with vocal fold paralysis. Conclusion: Thyroidectomy in children is a procedure with a higher complication rate and needs to be performed by a team of high-volume surgeons. This study focuses on the adverse events, so that those interested in the subject are aware of them.

Bethesda Classification and Cytohistological Correlation of Thyroid Nodules in a Brazilian Thyroid Disease Center.

BACKGROUND: The Bethesda System has been used to classify thyroid cytology in 6 categories besides presenting malignancy rates and respective approaches. Reference centers have validated its use by comparing its proposed malignancy rates with those in in their populations. However, to the best of our knowledge, there has been no corresponding study in Brazil. OBJECTIVES: To evaluate the performance of the Bethesda classification in a Brazilian thyroid reference center and correlate the results with cytohistological reports in patients referred to surgery. METHODS: Data records from 980 fine-needle aspiration (FNA) results were retrospectively analyzed, and, in patients who underwent surgery, the results were correlated with the cytohistological findings. RESULTS: 980 FNAs and 585 patients were evaluated. The incidence of each cytological category was: 11% nondiagnostic (ND), 59.6% benign, 7.1% (atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS), 8.5% follicular neoplasm or suspicious for follicular neoplasm (FN/SFN), 5.1% suspicious for malignancy (SM), and 8.3% malignant. The surgery rate was 41.8% (245/585). The malignancy rate in each category was: 6% benign, 12% AUS/FLUS, 20.8% FN/SFN, 72.5% SM, and 97.3% malignant. For ND nodules, the malignancy rate was 25.7% (66.6% multifocal and papillary microcarcinomas), a higher rate than in the literature. In this category, surgery was performed in multinodular goiters presenting with another nodule > 3.0 cm and/or with an FN/SFN, SM, or malignant cytological result. CONCLUSION: The Bethesda System can be applied to the Brazilian population, since the frequency and malignancy rates of each category were similar to those described by its classification. It is noteworthy that a higher risk of malignancy was observed in the ND cytological category.

Potential role of sorafenib as neoadjuvant therapy in unresectable papillary thyroid cancer.

Total thyroidectomy, radioiodine (RAI) therapy, and TSH suppression are the mainstay treatment for differentiated thyroid carcinomas (DTCs). Treatments for metastatic disease include surgery, external-beam radiotherapy, RAI, and kinase inhibitors for progressive iodine-refractory disease. Unresectable locoregional disease remains a challenge, as standard therapy with RAI becomes unfeasible. We report a case of a young patient who presented with unresectable papillary thyroid carcinoma (PTC), and treatment with sorafenib allowed total thyroidectomy and RAI therapy. A 20-year-old male presented with severe respiratory distress due to an enlarging cervical mass. Imaging studies revealed an enlarged multinodular thyroid gland, extensive cervical adenopathy, severe tracheal stenosis, and pulmonary micronodules. He required an urgent surgical intervention and underwent tracheostomy and partial left neck dissection, as the disease was deemed unresectable; pathology revealed PTC. Treatment with sorafenib was initiated, resulting in significant tumor reduction allowing near total thyroidectomy and bilateral neck dissection. Postoperatively, the patient underwent radiotherapy for residual tracheal lesion, followed by RAI therapy for avid cervical and pulmonary disease. The patient's disease remains stable 4 years after diagnosis. Sorafenib has been approved for progressive RAI-refractory metastatic DTCs. In this case report, we describe a patient with locally advanced PTC in whom treatment with sorafenib provided sufficient tumor reduction to allow thyroidectomy and RAI therapy, suggesting a potential role of sorafenib as an induction therapy of unresectable DTC.

Potential role of sorafenib as neoadjuvant therapy in unresectable papillary thyroid cancer

Summary Total thyroidectomy, radioiodine (RAI) therapy, and TSH suppression are the mainstay treatment for differentiated thyroid carcinomas (DTCs). Treatments for metastatic disease include surgery, external-beam radiotherapy, RAI, and kinase inhibitors for progressive iodine-refractory disease. Unresectable locoregional disease remains a challenge, as standard therapy with RAI becomes unfeasible. We report a case of a young patient who presented with unresectable papillary thyroid carcinoma (PTC), and treatment with sorafenib allowed total thyroidectomy and RAI therapy. A 20-year-old male presented with severe respiratory distress due to an enlarging cervical mass. Imaging studies revealed an enlarged multinodular thyroid gland, extensive cervical adenopathy, severe tracheal stenosis, and pulmonary micronodules. He required an urgent surgical intervention and underwent tracheostomy and partial left neck dissection, as the disease was deemed unresectable; pathology revealed PTC. Treatment with sorafenib was initiated, resulting in significant tumor reduction allowing near total thyroidectomy and bilateral neck dissection. Postoperatively, the patient underwent radiotherapy for residual tracheal lesion, followed by RAI therapy for avid cervical and pulmonary disease. The patient's disease remains stable 4 years after diagnosis. Sorafenib has been approved for progressive RAI-refractory metastatic DTCs. In this case report, we describe a patient with locally advanced PTC in whom treatment with sorafenib provided sufficient tumor reduction to allow thyroidectomy and RAI therapy, suggesting a potential role of sorafenib as an induction therapy of unresectable DTC.

Diagnosis and treatment of hypoparathyroidism: a position statement from the Brazilian Society of Endocrinology and Metabolism.

Objective To present an update on the diagnosis and treatment of hypoparathyroidism based on the most recent scientific evidence. Materials and methods The Department of Bone and Mineral Metabolism of the Sociedade Brasileira de Endocrinologia e Metabologia (SBEM; Brazilian Society of Endocrinology and Metabolism) was invited to prepare a document following the rules set by the Guidelines Program of the Associação Médica Brasileira (AMB; Brazilian Medical Association). Relevant papers were retrieved from the databases MEDLINE/PubMed, LILACS, and SciELO, and the evidence derived from each article was classified into recommendation levels according to scientific strength and study type. Conclusion An update on the recent scientific literature addressing hypoparathyroidism is presented to serve as a basis for the diagnosis and treatment of this condition in Brazil.

Diagnosis and treatment of hypoparathyroidism: a position statement from the Brazilian Society of Endocrinology and Metabolism

ABSTRACT Objective To present an update on the diagnosis and treatment of hypoparathyroidism based on the most recent scientific evidence. Materials and methods The Department of Bone and Mineral Metabolism of the Sociedade Brasileira de Endocrinologia e Metabologia (SBEM; Brazilian Society of Endocrinology and Metabolism) was invited to prepare a document following the rules set by the Guidelines Program of the Associação Médica Brasileira (AMB; Brazilian Medical Association). Relevant papers were retrieved from the databases MEDLINE/PubMed, LILACS, and SciELO, and the evidence derived from each article was classified into recommendation levels according to scientific strength and study type. Conclusion An update on the recent scientific literature addressing hypoparathyroidism is presented to serve as a basis for the diagnosis and treatment of this condition in Brazil.

Categorias citopatológicas III, IV e V de bethesda: correlação entre achados histopatológicos e epidemiológicos / Bethesda cytopathological categories III, IV and, V: correlation between histopathological and epidemiologic findings

Introdução: A padronização do Sistema de Bethesda declassificação citopatológica surgiu para facilitar a análise dosnódulos tireoidianos a avaliar seu risco de malignidade. Objetivo:O objetivo do estudo é analisar 92 pacientes submetidos àressecção parcial ou total de tireoide entre outubro/2010 ejunho/2013 em projeto de tratamento de doenças da tireoideem parceria entre a UNIFESP/EPM e o Hospital Albert Einsteinque foram classificados nas categorias III (19), IV (46) e V(27)de Bethesda. Dentre eles havia 84 mulheres e 8 homens, comidade média de 47 anos (23 - 73), 41 apresentando nódulo únicoe 51, mais de um nódulo. Resultados: A análise histopatológicaevidenciou carcinoma em 44 pacientes de modo que a incidêncianas categorias Bethesda III, IV e V foi 36%; 45,6% e 74%,respectivamente. Conclusão: Conclui-se que a opção deobservar nódulos Bethesda III é válida, mas de maneira criteriosa.

Parathyroid hormone: an early predictor of symptomatic hypocalcemia after total thyroidectomy.

OBJECTIVE: The purpose of this study was to evaluate if the measurement of peri-operative parathyroid hormone (PTH) is able to identify patients with increased risk of developing symptoms of hypocalcemia. SUBJECTS AND METHODS: Forty patients who underwent total thyroidectomy were studied prospectively. Ionized serum calcium and PTH were measured after induction of anesthesia, one hour (PTH1) and one day after surgery (PTH24). Patients were evaluated for symptoms of hypocalcemia and treated with calcium and vitamin D supplementation as necessary. RESULTS: Symptomatic hypocalcemia developed in 16 patients. Symptomatic patients had significant lower PTH1 and greater drops in PTH levels. The selection of 12.1 ng/L as PTH1 level cutoff level divided patients with and without symptoms with 93.7% sensitivity and 91.6% specificity. The selection of 73.5% as the cutoff value for PTH decrease resulted in 91.6% sensitivity and 87.5% specificity. CONCLUSION: PTH1 levels and the drop in PTH levels are reliable predictors of developing symptomatic hypocalcemia after total thyroidectomy.

Parathyroid hormone: an early predictor of symptomatic hypocalcemia after total thyroidectomy / Hormônio da paratireoide: um preditor precoce da hipocalcemia sintomática após a tireoidectomia total

OBJECTIVE: The purpose of this study was to evaluate if the measurement of peri-operative parathyroid hormone (PTH) is able to identify patients with increased risk of developing symptoms of hypocalcemia. SUBJECTS AND METHODS: Forty patients who underwent total thyroidectomy were studied prospectively. Ionized serum calcium and PTH were measured after induction of anesthesia, one hour (PTH1) and one day after surgery (PTH24). Patients were evaluated for symptoms of hypocalcemia and treated with calcium and vitamin D supplementation as necessary. RESULTS: Symptomatic hypocalcemia developed in 16 patients. Symptomatic patients had significant lower PTH1 and greater drops in PTH levels. The selection of 12.1 ng/L as PTH1 level cutoff level divided patients with and without symptoms with 93.7% sensitivity and 91.6% specificity. The selection of 73.5% as the cutoff value for PTH decrease resulted in 91.6% sensitivity and 87.5% specificity. CONCLUSION: PTH1 levels and the drop in PTH levels are reliable predictors of developing symptomatic hypocalcemia after total thyroidectomy.

OBJETIVO: O objetivo deste estudo é avaliar se a medida perioperatória do hormônio da paratireoide (PTH) pode identificar os pacientes com maior risco de desenvolver sintomas de hipocalcemia. SUJEITOS E MÉTODOS: Foram estudados quarenta pacientes submetidos à tireodiectomia total. A medida do cálcio sérico e do PTH foi feita após a indução anestésica, uma hora (PTH1) e um dia após a cirurgia. Os pacientes foram avaliados quanto à presença de sintomas de hipocalcemia e tratados com suplementação de cálcio e vitamina D quando necessário. RESULTADOS: Dezesseis pacientes apresentaram sintomas de hipocalcemia. Os pacientes sintomáticos apresentaram PTH1 significantemente menor e queda no PTH significativamente maior. Usando o valor de 12,1 ng/L como corte, conseguimos distinguir pacientes com e sem sintomas de hipocalcemia com sensibilidade de 93,7% e especificidade de 91,6%. Utilizando como corte a queda de 73,5% no valor do PTH, temos sensibilidade de 91,6% e especificidade de 87,5%. CONCLUSÃO: O PTH1 e a queda no PTH são bons preditores de hipocalcemia no pós-operatório de tireoidectomia total.

Parathyroid gland anatomical distribution and relation to anthropometric and demographic parameters: a cadaveric study.

Parathyroid glands play an important role in controlling calcium levels, which influence muscular contraction and neurotransmission. The number of variants, localization and ectopic positions make these glands tricky during surgical exploration. Detailed anatomical knowledge of these glands is fundamental to avoid postsurgical hypoparathyroidism, such as failures during thyroidectomy and parathyroid procedures. The purposes of this work were to study and report practical knowledge for surgeons in order to localize the glands. Dissections were performed on 56 cadavers. Gland identity was confirmed by histological study. Also, mediastinal tissue and the carotid sheath were treated with Carnoy's solution to identify ectopic glands. The thyroid gland was divided and sliced to identify parathyroid glands in the parenchymal and subcapsular space. Four or more parathyroid glands were found in 89.3% of the studied specimens. Mean gland weight was 33.1 mg, and its mean measurements were 6.7 × 3.9 × 2.0 mm. In more than 90% of the cases there was a correlation with the inferior laryngeal nerve and the parathyroid glands: the upper glands were located in medial positions, and the lower ones were found to be located laterally. In 42.8% of cases at least one ectopic gland was observed. The main ectopic regions were the mediastinum and thymus (19.6%), thyroid subcapsular space (12.5%) and thyroid parenchyma (5.4%). Quantity, gland characteristics and location were not influenced by anthropometric and demographic parameters. Here we show the high incidence of parathyroid glands positioned at "abnormal" locations, and as a controversial topic in endocrine surgery, this matter must be continuously studied and reported in the literature.