Thyrotropin (TSH) and thyroid autoimmunity are predictive factors for the incidental discovery of papillary thyroid microcarcinoma during thyroidectomy.

PURPOSE: To identify clinical, biological and pathological risk factors for the incidental discovery of papillary thyroid microcarcinomas (PTMCs) in patients undergoing thyroidectomy for presumed benign conditions. METHODS: Cross sectional, single center study, involving all consecutive patients (N = 3015) who were submitted to thyroid surgery between 2001-2019. All medical files were retrospectively reviewed. A total of 1961 patients in the benign group and 145 patients in PTMC group were analyzed. RESULTS: No significant differences in age, sex, body mass index, smoking status, thyroid volume or weight and preoperative thyroxine treatment between benign and PTMC groups were observed. Circulating anti- thyroid antibodies, histological thyroiditis and serum thyrotropin (TSH) were significantly associated with PTMC in univariable analysis. Independent risk factors for incidental PTMC by multivariable analysis where possible (OR: 1.51, 95% CI: 0.99-2.28) and certain (OR: 1.74, 95% CI: 1.09-2.78) thyroid autoimmunity (p = 0.002) and higher serum TSH (OR: 1.25, 95% CI: 1.08-1.45, p = 0.03), whereas thyroid lobectomy was associated with a lower risk of PTMC (OR: 0.40, 95% CI: 0.24-0.67, p < 0.001). The most frequent genetic alteration was BRAFV600E mutation, found in 56.3% of PTMC submitted to DNA sequencing. No association between clinical, biological or histological characteristics of PTMC and BRAFV600E mutation was observed. CONCLUSIONS: Thyroid autoimmunity and higher preoperative serum TSH level were independent predictors of PTMC incidentally discovered during thyroid surgery. Larger prospective studies are needed to better identify possible risk factors for papillary thyroid carcinoma initiation and progression.

Autonomously functioning thyroid nodules present intermediate malignancy risk according to European Thyroid Imaging Reporting and Data System (EU-TIRADS) and yield indeterminate cytology results.

Objectives: The aim was to evaluate the clinical, ultrasound (US) and, when indicated, the cytological and histological characteristics of autonomously functioning thyroid nodules (AFTN) in consecutive patients. Methods: A prospective, single-centre study was conducted between March 2018 and September 2021. In total, 901 consecutive patients were referred for thyroid workup and of 67 AFTN were evaluated. All enrolled patients underwent 99mTcO4 - scintigraphy, additional 123I scintigraphy only in case of normal serum TSH, evaluation of thyroid function, US examination using European Thyroid Imaging and Reporting Data System (EU-TIRADS), and US-guided fine needle aspiration (FNA) cytology when indicated. All indeterminate FNA samples were subjected to DNA sequencing analysis. Results: More than half of the evaluated patients with AFTN were euthyroid; median serum TSH was 0.41 (IQR: 0.03-0.97) mU/L. The median AFTN size measured by US was 27.0 (IQR: 21.1-35.0) mm. 28.4% of AFTN were classified as EU-TIRADS score 3 and 71.6% as EU-TIRADS score 4, indicating that the majority of AFTN had intermediate risk for malignancy according to US. Out of the 47 AFTN subjected to cytological evaluation, 24 (51%) yielded indeterminate FNA results. DNA sequencing revealed pathogenic TSHR and GNAS mutations in 60% of cases. No malignancy was detected at final histology in surgically excised AFTN (n = 12). Conclusions: Of the 67 AFTN evaluated in this study, 50% presented with normal serum TSH, 70% displayed ultrasound features suggesting an intermediate malignancy risk and 50% of the AFTN submitted to cytology yielded indeterminate results. No malignant AFTN was detected.

Thyroid autoimmunity and pregnancy in euthyroid women.

Women with thyroid autoimmunity (TAI), predominately characterized by increased levels of thyroid peroxidase antibody (TPOAb), are at risk for developing pregnancy related complications. In this review, we discuss the importance of TAI during natal and perinatal stages. Before pregnancy, TAI is associated with higher mean serum TSH levels and certain causes of subfertility. During pregnancy, TAI increases the risk of an insufficient response of the thyroid to an increasing strain induced by pregnancy, and consequently (subclinical) hypothyroidism might develop. Euthyroid women with TAI have a higher rate of maternal and foetal complications, but it seems that causality cannot be pinned down to thyroid dysfunction alone. Almost half of the women known with TAI prior to pregnancy will also develop post-partum thyroiditis (PPT). However, any relation between PPT and post-partum depression remains uncertain. More research is required to explain possible associations between TAI and pregnancy morbidities, and studies should focus on a better understanding of TAI as such. Given the many unanswered questions, at present, it is not recommended to screen all (potentially) pregnant women for the presence of TAI.

Metabolic Changes after Radioiodine Correction of Grade 1 and Grade 2 Subclinical Hyperthyroidism.

OBJECTIVE: Endogenous subclinical hyperthyroidism (eSCH) is defined by subnormal serum thyroid-stimulating hormone (TSH) level. There is limited evidence of metabolic changes induced by eSCH. The aim of our work was to evaluate changes in BMI and lipid parameters after radioiodine treatment in patients with grade 1 (TSH: 0.1-0.39 mlU/L) and 2 (TSH <0.1 mlU/L) eSCH. DESIGN: A retrospective study was performed on 74 patients with eSCH caused by benign autonomous nodular goiter which was treated with radioiodine. METHODS: We assessed BMI, lipids parameters, and TSH after radioiodine therapy. The 12-month follow-up time point was used to compare the primary outcome variables. TSH was measured by the electrochemiluminescence method. RESULTS: After radioiodine therapy, the absolute and relative increases in BMI at 12 months were significantly higher in the grade 2 group than in the grade 1 group (1.07 ± 0.27 kg/m2 vs. 0.26 ± 0.15 kg/m2, respectively; p = 0.023 and 4.01 ± 0.98% vs. 1.01 ± 0.56%, respectively; p = 0.026). Compared to baseline, significant increases in the levels of total cholesterol and LDL were observed after treatment in the grade 2 eSCH group (16.7 ± 4.5 mg/dL p < 0.01 and 14.3 ± 4.1 mg/dL p < 0.01, respectively) but not in the grade 1 group. In a multivariate model, a negative correlation was observed between pretreatment TSH levels and absolute BMI gain (p < 0.01). CONCLUSIONS: After correction of eSCH, increases in BMI and LDL levels were observed only in patients with grade 2 eSCH. Pretreatment serum TSH was the main independent factor associated with BMI changes after radioiodine treatment.

Dissecting the Role of Thyrotropin in the DNA Damage Response in Human Thyrocytes after 131I, γ Radiation and H2O2.

BACKGROUND: The early molecular events in human thyrocytes after 131I exposure have not yet been unravelled. Therefore, we investigated the role of TSH in the 131I-induced DNA damage response and gene expression in primary cultured human thyrocytes. METHODS: Following exposure of thyrocytes, in the presence or absence of TSH, to 131I (ß radiation), γ radiation (3 Gy), and hydrogen peroxide (H2O2), we assessed DNA damage, proliferation, and cell-cycle status. We conducted RNA sequencing to profile gene expression after each type of exposure and evaluated the influence of TSH on each transcriptomic response. RESULTS: Overall, the thyrocyte responses following exposure to ß or γ radiation and to H2O2 were similar. However, TSH increased 131I-induced DNA damage, an effect partially diminished after iodide uptake inhibition. Specifically, TSH increased the number of DNA double-strand breaks in nonexposed thyrocytes and thus predisposed them to greater damage following 131I exposure. This effect most likely occurred via Gα q cascade and a rise in intracellular reactive oxygen species (ROS) levels. ß and γ radiation prolonged thyroid cell-cycle arrest to a similar extent without sign of apoptosis. The gene expression profiles of thyrocytes exposed to ß/γ radiation or H2O2 were overlapping. Modulations in genes involved in inflammatory response, apoptosis, and proliferation were observed. TSH increased the number and intensity of modulation of differentially expressed genes after 131I exposure. CONCLUSIONS: TSH specifically increased 131I-induced DNA damage probably via a rise in ROS levels and produced a more prominent transcriptomic response after exposure to 131I.

Graves' disease, multinodular goiter and subclinical hyperthyroidism.

Subclinical hyperthyroidism is a common clinical entity, defined by serum TSH below the reference range, with normal FT4 and FT3 levels in an asymptomatic patient. Whether or not subclinical hyperthyroidism should be treated remains a matter of debate. Cross-sectional and longitudinal population-based studies demonstrate association of subclinical hyperthyroidism with risk of atrial fibrillation and osteoporosis, and with cardiovascular and all-cause mortality. However, there are no randomized clinical trials addressing whether long-term health outcomes are improved by treating subclinical hyperthyroidism; in the absence of evidence one way or the other, it seems appropriate to use decision trees taking account of TSH concentration and presence of risk factors (age>65 years or post-menopause, osteoporosis and cardiac disease).

Factors contributing to the resistance of the thyrocyte to hydrogen peroxide.

We studied the mechanism that may explain the relative resistance of thyrocytes to H2O2 compared to other cell types. Ability to degrade H2O2, glutathione peroxidase (GPx) activity, heme oxygenase-1 (HO-1) expression, cell survival and capacity to repair DNA damage after H2O2 exposure or irradiation were measured in human thyrocytes in primary culture and compared to the values obtained in human T-cells and different cell lines. Compared to other cell types, thyrocytes presented a low mortality rate after H2O2 exposure, rapidly degraded extracellular H2O2 and presented a high basal seleno-dependent GPx activity. Only in thyrocytes, H2O2 up-regulated GPx activity and expression of HO-1 mRNA. These effects were not reproduced by irradiation. DNA damage caused by H2O2 was more slowly repaired than that caused by irradiation and not repaired at all in T-cells. Our study demonstrates that the thyrocyte has specific protective mechanisms against H2O2 and its mutagenic effects.

Unilateral Adrenalectomy Could Be a Valid Option for Primary Nodular Adrenal Disease: Evidence From Twins.

Primary pigmented nodular adrenal disease (PPNAD) accounts for <1% of ACTH-independent Cushing syndrome. We describe the case of twin female patients with PPNAD who both had sustainable disease control after unilateral adrenalectomy, which corroborates current evidence in favor of unilateral adrenalectomy for a subset of patients with PPNAD. Patient A presented with a 10-kg weight gain over the past year and facial plethora. Diagnostic evaluation revealed abolition of normal cortisol rhythm with suppressed ACTH levels, normal adrenal CT and MRI imaging and a slightly left-predominant adrenal uptake on 131I iodomethyl norcholesterol scintigraphy coupled with single-photon emission CT/CT. PPNAD was confirmed after genetic testing revealed a known pathogenic PRKA1A mutation (c.709 (-7-2) del6). At that time, her twin sister (patient B) was asymptomatic. Patient A underwent successful unilateral adrenalectomy and histology confirmed PPNAD. Two years after initial onset of symptoms in patient A, patient B was seen for the same subtle symptoms of progressive weight gain. Diagnostic test results were identical, revealing the same clinical features and mutational status as patient A. Patient B also underwent unilateral adrenalectomy with a favorable outcome. Follow-up 3 years after surgery for patient A and 18 months for patient B showed sustained disease control without recurrence and uncompromised quality of life, with no adrenal insufficiency having occurred. Unilateral adrenalectomy can be a successful therapeutic approach for patients with PPNAD with a mild phenotype without the risk and the inconvenience of subsequent adrenal insufficiency, which alters quality of life.

Total thyroidectomy: a clue to understanding the metabolic changes induced by subclinical hyperthyroidism?

OBJECTIVE: The effects of endogenous subclinical hyperthyroidism (eSCH) on heart and bone have been well documented. There are only limited data available regarding the impact of eSCH on weight regulation and lipid metabolism. Our aim was to evaluate the changes in body weight and metabolic parameters after total thyroidectomy in patients with pre-operative eSCH compared with pre-operative patients with euthyroid (EUT). DESIGN: A retrospective study of 505 patients who underwent total thyroidectomy for benign multinodular goitre in an academic hospital in Brussels (Belgium) was performed. PATIENT'S MEASUREMENTS: Two hundred and 25 patients were included (eSCH group: n = 74; EUT group: n = 151). The mean follow-up time was 26·1 ± 0·8 months and was similar in both groups. RESULTS: Absolute BMI gain was significantly greater in the eSCH group than in the EUT group (1·11 ± 0·17 vs 0·33 ± 0·13 kg/m2 ; P = 0·003). A significant increase in LDL cholesterol was observed in the eSCH group (16·1 ± 3·8 mg/dl; P < 0·001) but not in the EUT group (0·0 ± 3·0 mg/dl; P = 0·88). In a multivariate model, pre-operative TSH levels were the main factor significantly associated with increases in BMI or LDL cholesterol. Post-operative median TSH levels and L-thyroxine substitution were similar in both groups. CONCLUSION: After total thyroidectomy, increases in weight and serum cholesterol were observed in the eSCH group. Given that post-operative TSH levels were similar in the two groups, these observations are probably due to the correction of eSCH, suggesting a direct effect of eSCH on body weight regulation and lipid metabolism.

Is there still a role for thyroid scintigraphy in the workup of a thyroid nodule in the era of fine needle aspiration cytology and molecular testing?

Thyroid scintigraphy is now rarely used in the work-up of a thyroid nodule except in the presence of a low TSH value. Therefore, autonomously functioning thyroid nodules (AFTNs) with a normal TSH value are diagnosed only in the rare medical centers that continue to use thyroid scan systematically in the presence of a thyroid nodule. In this review, we discuss the prevalence of AFTN with a normal TSH level and the possible consequences of performing fine needle aspiration cytology (FNAC) in an undiagnosed AFTN. We also discuss the risk of malignant AFTN which may be higher than previously stated.

Thyroid lobectomy is an effective option for unilateral benign nodular disease.

OBJECTIVE: The use of thyroid lobectomy in the treatment of unilateral, benign nodules is limited by the potential of nodular recurrence in the remaining lobe. This study aimed to assess the rate and clinical impact of nodular recurrence in the contralateral lobe after thyroid lobectomy and to identify predictive factors of recurrence. DESIGN: Single-centre retrospective study. PATIENTS: Records of patients that underwent lobectomy for unilateral thyroid nodules between 1991 and 2010 were reviewed and 270 patients were included. Exclusion criteria were: presence of contralateral nodule(s) ≥5 mm on preoperative ultrasound, diagnosis of cancer necessitating completion thyroidectomy or pseudonodules. Recurrence was defined as the occurrence of nodule(s) ≥5 mm in the remaining lobe on at least one postoperative ultrasound. A set of clinical, imaging, histological and biochemical parameters was tested as predictors of recurrence using logistic regression. RESULTS: After a median follow-up of 78 months (range, 12-277 months), the global recurrence rate was 42% and recurrence of nodules of a size ≥1 cm occurred in 19%. Reoperation rate was 1·1%. 90% of patients were treated postoperatively by levothyroxine. Median time to nodular recurrence was 4 years. Preoperative contralateral lobe volume and resected thyroid weight were identified as significant predictors of recurrence (P = 0·045 and P = 0·03 respectively). CONCLUSIONS: Thyroid lobectomy is an effective therapeutic strategy for unilateral, benign nodules, resulting in a low rate of clinically relevant nodular relapse in a mildly iodine-deficient area. Patients with uninodular disease and a contralateral lobe of normal size are particularly good candidates for lobectomy.

Thiamazole Pretreatment Lowers the (131)I Activity Needed to Cure Hyperthyroidism in Patients With Nodular Goiter.

CONTEXT: Relatively low radioiodine uptake (RAIU) represents a common obstacle for radioiodine ((131)I) therapy in patients with multinodular goiter complicated by hyperthyroidism. OBJECTIVE: To evaluate whether thiamazole (MTZ) pretreatment can increase (131)I therapeutic efficacy. DESIGN AND SETTING: Twenty-two patients with multinodular goiter, subclinical hyperthyroidism, and RAIU < 50% were randomized to receive either a low-iodine diet (LID; n = 10) or MTZ 30 mg/d (n = 12) for 42 days. Thyroid function and 24-hour RAIU were measured before and after treatment. Thyroid volume was evaluated by either magnetic resonance imaging or single photon emission computed tomography. RESULTS: Mean 24-hour RAIU increased significantly from 32 ± 10% to 63 ± 18% in the MTZ group (P < .001). Consequently, there was a 31% decrease in the calculated median therapeutic (131)I activity after MTZ (P < .05). No significant changes in 24-hour RAIU were observed after diet. In the MTZ group, median serum TSH levels increased significantly by 9% and mean serum free T4 and free T3 concentrations decreased by 22% and 15%, respectively, whereas no changes in thyroid function were observed in the LID group. Thyroid volume did not significantly change in either of the two groups. At 12 months after radioiodine treatment, median serum TSH was within the normal range in both groups. CONCLUSIONS: MTZ treatment before (131)I therapy resulted in an average 2-fold increase in thyroid RAIU and enhanced the efficiency of radioiodine therapy assessed at 12 months. MTZ pretreatment is therefore a safe, easily accessible alternative to recombinant human TSH stimulation and a more effective option than LID.