Objective: To report the results of cytology and histology obtained for a series of systematically resected thyroid nodules ≥ 4 cm. Methods: A group of 151 patients with thyroid nodules ≥ 4 cm was submitted to surgery despite the cytology result. Results: Malignancy was confirmed histologically in 22.5% of the patients. Excluding cases of insufficient material, cytology was benign in only 3/31 carcinomas (90.3% sensitivity). The frequency of malignancy was 35% among nodules with indeterminate cytology (follicular neoplasm), and there was a predominance (77%) of papillary carcinoma. The negative predictive value of benign cytology was 96.4%. Conclusions: The false-negative rate of cytology in thyroid nodules ≥ 4 cm does not justify systematic resection of these nodules in asymptomatic patients with benign cytology. Arq Bras Endocrinol Metab. 2009;53(9):1143-5Keywords Thyroid nodule; cytology; benign resumo Objetivo: Reportar os resultados da citologia e da histologia em uma série de nódulos tireoidianos ≥ 4 cm sistematicamente ressecados. Métodos: Foram submetidos à cirurgia 151 pacientes com nódulo tireoidiano ≥ 4 cm, a despeito do resultado da citologia. Apenas a histologia referente a este nódulo foi considerada nos resultados. Resultados: Malignidade foi confirmada histologicamente em 22,5% dos pacientes. Excluindo os casos com material insuficiente, a citologia foi benigna somente em 3/31 carcinomas (sensibilidade 90,3%). A frequência de malignidade foi de 35% nos nódulos com citologia indeterminada (neoplasia folicular), predominando o carcinoma papilífero (77%). O valor preditivo negativo da citologia benigna foi 96,4%. Conclusões: A taxa de falso-negativo da citologia em nódulos tireoidianos ≥ 4 cm não justifica a ressecção sistemática destes em pacientes assintomáticos com citologia benigna. Arq Bras Endocrinol Metab. 2009;53(9):1143-5 Descritores Nódulo da glândula tireoide; citologia; benigna

Objective: To evaluate the contribution of 131 I scintigraphy and ultrasonography to the prediction of malignancy in thyroid nodules with indeterminate cytology in euthyroid patients. Subjects and methods: The sample consisted of 102 patients with thyroid nodules, submitted to FNAC and presenting an indeterminate cytological diagnosis (follicular neoplasm). Results: Malignancy was observed in 19/25 (76%) nodules with suspicious ultrasonographic characteristics versus 5/77 (6.5%) without suspicious findings. When 131 I scintigraphy showed a cold or hot nodule, the chance of malignancy was 38.5% and 2.5%, respectively. This exam was inconclusive in 10% of the patients. Conclusions: Surgery is indicated when a thyroid nodule with indeterminate cytology exhibits suspicious ultrasonographic characteristics. Otherwise, 131 I scintigraphy can exclude thyroidectomy when reveals uptake in the nodule, which is observed in half the cases. Arq Bras Endocrinol Metab. 2010;54(1):56-9 Keywords Thyroid nodule; indeterminate cytology; radionuclide imaging; ultrasonography resumo Objetivo: Avaliar a contribuição da cintilografia com 131 I e da ultrassonografia na predição de malignidade em nódulos tireoidianos com citologia indeterminada em pacientes eutireoidianos. Sujeitos e Métodos: A amostra foi composta por 102 pacientes com nódulos tireoidianos submetidos à punção aspirativa com agulha fina (PAAF), apresentando citologia indeterminada (neoplasia folicular). Resultados: Malignidade foi encontrada em 19/25 (76%) nódulos suspeitos na ultrassonografia versus 5/77 (6,5%) naqueles sem características suspeitas. Quando a cintilografia com 131 I mostrou nódulo hipo-ou hipercaptante, a chance de malignidade foi 38,5% e 2,5%, respectivamente, e em 10% dos pacientes esse exame foi inconclusivo. Conclusões: Cirurgia está indicada quando um nódulo tireoidiano com citologia indeterminada exibe características ultrassonográficas suspeitas. Quando não as exibe, a cintilografia com 131 I pode dispensar a tireoidectomia se revelar captação correspondente ao nódulo, o que ocorre em metade dos casos. Arq Bras Endocrinol Metab. 2010;54(1):56-9

OBJECTIVE: The levothyroxine withdrawal (L-T4) for some weeks results in prolonged exposure to elevated TSH. In contrast, administration of recombinant human TSH (rhTSH) promotes a short period of hyperthyrotropinemia. The objective of this study was to compare the area under the curve (AUC) of TSH obtained after L-T4 withdrawal versus administration of rhTSH. METHODS: Thirty patients received 0.9 mg rhTSH for two consecutive days, and 64 were prepared by L-T4 withdrawal for four weeks, with the latter being reintroduced 48 hour after 131I. Measurement of TSH were performed before the first rhTSH ampoule; immediately before and seven and 14 days after 131I; before L-T4 withdrawal; and, weekly, up to two months after 131I. RESULTS: The AUC obtained after rhTSH was 4.6 times smaller than that obtained after L-T4 withdrawal (532 versus 2,423 mIU/L per day). It should be emphasized that, on average, in the latter group, 58.5% of the AUC corresponded to the period after reintroduction of hormone therapy. CONCLUSIONS: Surprising difference in the TSH AUC was demonstrated between rhTSH administration versus L-T4 withdrawal.

No abstract

T he nadir growth hormone (n-GH) in the oral glucose tolerance test (OGTT) is the gold standard for the demonstration of secretory autonomy of this hormone and a laboratory parameter necessary for the diagnosis of acromegaly (1,2). Although measurement of GH after oral glucose overload is not recommended during treatment with somatostatin analogs or GH receptor antagonists (3), normalization of n-GH continues to be necessary for the definition of "control" after surgical treatment of acromegaly (3). Nadir GH levels vary according to the assay used (4-7) and are influenced by gender, age and body mass index 8)]. The inverse correlation with BMI observed in normal subjects (4,6,8) and acromegalic patients (9) indicates the need for adjusting the n-GH cut-off as a function of BMI (4,6,8). We have previously defined n-GH reference values in subjects with a BMI ≤ 27 kg/m 2 (5). The possibility that the current reference values are inadequate (overestimated) for obese subjects led to the elaboration of the present study, for which the objective was to evaluate the n-GH in the OGTT in subjects with a BMI ≥ 30 kg/m 2 . A total of 200 volunteers (120 women and 80 men) ranging in age from 18 to 70 years (median of 44 years), matched with 200 subjects from the previous study (5), who had a BMI ≥ 30 kg/m 2 (median of 34.8 kg/m 2 ) were studied. The selection criteria, protocol and statistical analysis are described in detail in the previous study (5). Briefly, apparently healthy subjects (excluding pregnant women) without associated diseases who were not using medications that might interfere with GH levels and who presented no abnormalities upon minimum laboratory assessment (glycemia, blood count, albumin, creatinine, TSH, GOT, GPT and bilirubin) were selected. The study was approved by the Ethics Committee of Santa Casa de Belo Horizonte.The GH Immulite kit (Diagnostic Products Corporation, Los Angeles, CA) was used for the measurement of GH since it is the kit most widely used in Brazil. In addition, the kit meets the requirements of calibrated standards against > 95% pure preparations of GH 22 kDa (10), its specificity for the 22 and 20 kDa isoforms is known (4), and its intra-and interassay sensitivity and variability have been previously established (5,11). The cut-off was defined as the 97.5th percentile of the values found. The Spearman correlation test was used to analyze the correlation between n-GH and age, BMI. The nonparametric Kruskal-Wallis test and the parametric Shapiro-Wilk test were used to compare GH values obtained between groups. P values < 0.05 were considered to be statistically significant.The n-GH cut-off values for obese women and men were 0.35 µg/L and 0.15 µg/L (p < 0.05), respectively. No correlation was observed between n-GH levels and age. However, a difference was found when comparing women ≤ 35 years (n = 40) versus > 35 years (n = 80), with higher values in the former (n-GH cut-off: 0.42 µg/L versus 0