Management of endocrine surgical disorders during COVID-19 pandemic: expert opinion for non-surgical options.

PURPOSE: The COVID-19 pandemic brought unprecedented conditions for overall health care systems by restricting resources for non-COVID-19 patients. As the burden of the disease escalates, routine elective surgeries are being cancelled. The aim of this paper was to provide a guideline for management of endocrine surgical disorders during a pandemic. METHODS: We used Delphi method with a nine-scale Likert scale on two rounds of voting involving 64 experienced eminent surgeons and endocrinologists who had the necessary experience to provide insight on endocrine disorder management. All voting was done by email using a standard questionnaire. RESULTS: Overall, 37 recommendations were voted on. In two rounds, all recommendations reached an agreement and were either endorsed or rejected. Endorsed statements include dietary change in primary hyperparathyroidism, Cinacalcet treatment in secondary hyperparathyroidism, alpha-blocker administration for pheochromocytoma, methimazole ± ß-blocker combination for Graves' disease, and follow-up for fine-needle aspiration results of thyroid nodules indicated as Bethesda 3-4 cytological results and papillary microcarcinoma. CONCLUSION: This survey summarizes expert opinion for the management of endocrine surgical conditions during unprecedented times when access to surgical treatment is severely disrupted. The statements are not applicable in circumstances in which surgical treatment is possible.

Corticomedullary Mixed Tumor of the Adrenal Gland with Apparent 18F-Fluorodeoxyglucose Activity But No 68GA-DOTATATE Uptake on Positron Emission Tomography/Computed Tomography.

Corticomedullary mixed tumor (CMT) is a single adrenal tumor mass composed histologically by an admixture of adrenal cortical and medullary cells. It is a rare condition, with approximately 20 cases reported to date. To our knowledge, the positron emission tomography (PET) imaging findings of this mostly benign tumor have not been reported in the literature. We present a case of CMT who was evaluated with both 18F-fluorodeoxyglucose (18F-FDG) and 68Ga-DOTATATE. The hypermetabolic tumor seen on 18F-FDG PET/computed tomography scan showed no abnormal uptake by 68Ga-DOTATATE.

BRAF V600E mutation in papillary thyroid cancer is correlated with adverse clinicopathological features but not with iodine exposure.

INTRODUCTION: BRAFV600E activating mutation is the most frequent genetic abnormality in the pathogenesis of papillary thyroid carcinoma. We aimed to evaluate the association between BRAFV600E mutation and well-established prognostic clinicopathological characteristics as well as iodine exposure. MATERIAL AND METHODS: From 2000 to 2012, the data of PTC patients admitted to Dr. Lutfi Kirdar Kartal Education and Research Hospital in Turkey were reviewed retrospectively. Clinicopathological parameters were collected. BRAFV600E mutation was analysed by DNA sequencing method in tumour specimens. We hypothesised thatBRAFV600E mutation prevalence is positively correlated with prolonged iodine exposure and expected to be higher in the second half of the recruitment period due to the increment in time spent from the iodisation process of the table salt in our country. Thus, iodine exposure was categorised as short-term (2000-2006) and long-term (2006-2012). RESULTS: A total of 197 patients were accrued. The study population predominantly consisted of conventional variant. A statistically significant relationship was observed betweenBRAFV600E mutation presence and age (p = 0.03), conventional variant PTC (p = 0.00002), T4 stage (p = 0.002), vascular invasion (p = 0.036), thyroid capsule invasion (p < 0.00001), extrathyroidal tissue invasion (p < 0.00001), and lymph node metastasis (p < 0.00001). When categorised as long-term and short-term, iodine exposure was not statistically significantly related withBRAFV600E mutation; however, there were far more PTC cases in the long-term group (86.3% vs. 13.7%). CONCLUSION: We revealed that BRAFV600E mutation is associated with adverse clinicopathological parameters. There appeared to be no relation between long-term iodine exposure and BRAFV600E.

The Mitochondrial DNA Control Region Might Have Useful Diagnostic and Prognostic Biomarkers for Thyroid Tumors.

The literature suggests that mitochondrial DNA (mtDNA) defects are associated with a large number of diseases including cancers. The role of mtDNA variations in thyroid cancer is a highly controversial topic. Therefore, we investigated the role of mt-DNA control region (CR) variations in thyroid tumor progression and the influence of mtDNA haplogroups on susceptibility to thyroid tumors. For this purpose, in total, 108 hot thyroid nodules (HTNs), 95 cold thyroid nodules (CTNs), 48 papillary thyroid carcinoma (PTC) samples with their surrounding tissues and 104 healthy control subjects' blood samples were screened for all mtDNA CR variations using Sanger sequencing. We found that MtDNA haplogroup U was significantly associated with susceptibility to benign thyroid entities. In addition, eight single nucleotide polymorphisms (SNPs) (T146C, G185A, C194T, C295T, G16129A, T16304C, A16343G and T16362C) in the mtDNA CR were associated with the occurrence of benign and malign thyroid nodules in the Turkish population. As compared with samples taken from a healthy Turkish population and HTNs, the frequency of C7 repeats in D310 polycytosine sequence was found to be higher in CTNs and the PTC samples. In addition, the frequency of somatic mutations in mtMSI regions including T16189C and D514 CA dinucleotide repeats were found to be higher in PTC samples than benign thyroid nodules. Conversely, the frequency of somatic mutations in D310 was found to be higher in HTNs than CTNs and PTCs. In conclusion, mtDNA D310 instability does not play a role in the tumorigenesis of PTC but the results indicate that it might be used as a diagnostic clonal expansion biomarker for premalignant thyroid tumor cells. In addition, D514 CA instability might be considered as a prognostic biomarker for benign to malign transformation in thyroid tumors.

Recurrent EZH1 mutations are a second hit in autonomous thyroid adenomas.

Autonomous thyroid adenomas (ATAs) are a frequent cause of hyperthyroidism. Mutations in the genes encoding the TSH receptor (TSHR) or the Gs protein α subunit (GNAS) are found in approximately 70% of ATAs. The involvement of other genes and the pathogenesis of the remaining cases are presently unknown. Here, we performed whole-exome sequencing in 19 ATAs that were paired with normal DNA samples and identified a recurrent hot-spot mutation (c.1712A>G; p.Gln571Arg) in the enhancer of zeste homolog 1 (EZH1) gene, which codes for a catalytic subunit of the polycomb complex. Targeted screening in an independent cohort confirmed that this mutation occurs with high frequency (27%) in ATAs. EZH1 mutations were strongly associated with known (TSHR, GNAS) or presumed (adenylate cyclase 9 [ADCY9]) alterations in cAMP pathway genes. Furthermore, functional studies revealed that the p.Gln571Arg EZH1 mutation caused increased histone H3 trimethylation and increased proliferation of thyroid cells. In summary, this study revealed that a hot-spot mutation in EZH1 is the second most frequent genetic alteration in ATAs. The association between EZH1 and TSHR mutations suggests a 2-hit model for the pathogenesis of these tumors, whereby constitutive activation of the cAMP pathway and EZH1 mutations cooperate to induce the hyperproliferation of thyroid cells.

The role of insulin-like growth factor 1 in the development of benign and malignant thyroid nodules.

OBJECTIVE: This study aims to investigate the role of IGF-1 in the development of nodular thyroid disease. MATERIAL AND METHODS: A total number of 100 consecutive patients operated for nodular thyroid disease in our institution were included in this prospective study. In addition to classical pathological examinations, nodules and extranodular healthy tissues were sampled and immunochemically stained for IGF-1. The materials were independently evaluated using an Allred Scoring System ranging from 0 to 8. If the score was ≥1, the tissue was accepted as IGF-1 positive. RESULTS: IGF-1 positivity was observed in 88% and 58% of the samples obtained from nodules and extranodular healthy tissues, respectively. Allred 8-unit scores were higher in benign nodules (n=89; 4.1±2.3) and papillary carcinomas (n=7; 6.7±1.3), than in extranodular healthy tissues in the same patients (2.3±2.3 and 3.3±1.9, respectively); and higher in papillary carcinomas than in benign nodules, when the scores were compared to each other (p<0.01 for all comparisons). CONCLUSIONS: Allred 8-unit scores for IGF-1 increase in the presence of benign thyroid nodules, papillary cancer. The results of our study support the findings of previous studies demonstrating the role of IGF-1 in the development of thyroidal nodules.

Alterations of NIS expression in functioning thyroid nodules.

OBJECTIVES: This study aimed to analyze both the level and the cell site of the sodium-iodide symporter (NIS) protein expression in autonomously functioning thyroid nodules (AFTNs) and extranodular thyroid tissues. In addition, this study sought to compare the clinical results of patients with the levels of human NIS (hNIS) protein expression. PATIENTS AND METHODS: The histological slides consisted of 36 AFTNs and 31 extranodular thyroid tissues from 28 patients (5 males, 23 females; mean age 54.5±11.0 years; range 37 to 72 years) who underwent surgery for toxic multinodular goitre. The expression of NIS protein was investigated by immunohistochemistry in paraffin-embedded tissue sections using anti-hNIS monoclonal antibody by the labeled streptavidin-biotin method. RESULTS: The percentage of hNIS positive follicular cells was significantly higher in the AFTNs (13.33±12.09) than in the extranodular thyroid tissues (1.35±3.03). Staining for hNIS was mostly confined to the cell membrane in the AFTNs (88.9%) and in the extranodular thyroid tissues (54.5%). The clinical parameters and nodule volume did not establish any correlation with hNIS immunoreactivity. CONCLUSION: Our data indicate that functioning nodules express higher amounts of NIS protein than the extranodular thyroid tissue, but the level of hNIS immunoreactivity was lower than had been reported in the previous literature. This result may be due to interindividual variability between different populations, and iodine status. Furthermore, the localization of the NIS protein might not give an indication of its functional status.

Myasthenia gravis and autoimmune Addison disease in a patient with thymoma.

The association of thymoma with myasthenia gravis has been well documented. However, the relationship between these two syndromes and Addison disease are very rarely encountered in clinical practice. We report on a 32-year-old man who underwent a resection for thymoma 48 months ago. The diagnosis of Addison disease was made followed by a diagnosis of myasthenia gravis on the basis of a high titer of acetylcholine receptor levels. The treatment of oral prednisolone 7.5 mg/day and oral prostigmine 180 mg/day was initiated. His symptoms and physical signs were improved after this treatment. To our knowledge, this is the fourth reported case of thymoma synchronously associated with myasthenia gravis and Addison disease.

Cases of borderline in vitro constitutive thyrotropin receptor activity: how to decide whether a thyrotropin receptor mutation is constitutively active or not?

BACKGROUND: Previous in vitro data for several constitutively activating thyrotropin receptor (TSHR) mutations reported divergent results for the constitutive activity of the same mutations. Moreover, several case reports have highlighted the difficulties in determining whether a TSHR mutation is constitutively active or not. Retrospectively, this has repeatedly been the case for mutants with only a slight increase of basal cAMP activity. We re-examined 10 previously described TSHR germline mutations with minor increases of basal cAMP activity and analyzed the influences of the cell line and vector system on the basal receptor activity. METHODS: TSHR mutations were characterized by determination of cell surface expression, cAMP accumulation, and linear regression analysis of constitutive activity. RESULTS: Re-examination of the previously described constitutively active TSHR germline mutations did not show constitutive activity for R310C and N670S as tested in COS-7 cells and confirmed constitutive activity for the other eight mutations. However, mutant N670S showed a slight but significant increase of basal activity measured by linear regression analysis when analyzed in HEK(GT) cells transiently transfected with pcDNA but not with the pSVL vector. This was not the case for R310C. CONCLUSIONS: Our findings indicate that current methods to precisely classify mutants with only a slight increase of the basal activity as constitutively active are limited. The results concerning the level of the basal activity can be influenced by the vector and/or the cell system. A comprehensive clinical characterization of the respective patients appears as a necessary and promising adjunct for the activity classification of these borderline mutations.

A new silent germline mutation of the TSH receptor: coexpression in a hyperthyroid family member with a second activating somatic mutation.

BACKGROUND: Up to date, three thyroid-stimulating hormone receptor (TSHR) germline variants have been reported for which no functional consequences have been detected by in vitro characterizations. However, familial nonautoimmune hyperthyroidism and hot nodules are clearly associated with constitutively activating TSHR germline mutations. We describe a family with a new TSHR germline mutation that is associated with euthyroidism in 13 family members and hyperthyroidism in 1 family member. METHODS: Mutation analysis of the TSHR gene was performed by denaturing gradient gel electrophoresis. TSHR constructs were characterized by determination of cell surface expression, 3'-5'-cyclic adenosine monophosphate (cAMP) accumulation, and constitutive cAMP activity. RESULTS: A novel TSHR germline mutation (N372T) was found in a man who presented with thyrotoxicosis. The mutation was also detected in 13 family members, all of whom were euthyroid. Interestingly, an additional constitutively active somatic mutation (S281N) was identified on the second parental TSHR allele of the hyperthyroid index patient. Linear regression analysis showed a lack of constitutive activity for N372T. Moreover, coexpression studies of N372T with S281N did not reveal any evidence for a functional influence of N372T on the constitutively active mutation (CAM). CONCLUSIONS: N372T is unlikely to cause altered thyroid function. This is consistent with the finding that only the index patient with the additional somatic mutation S281N was hyperthyroid.

Similar prevalence of somatic TSH receptor and Gsalpha mutations in toxic thyroid nodules in geographical regions with different iodine supply in Turkey.

OBJECTIVE: Differences in iodine intake could account for the variable prevalences reported for somatic TSH receptor (TSHR) mutations in toxic thyroid nodules (TTNs). However, this question has not been settled, since no study has yet determined the TSHR mutation prevalence in regions with different iodine supplies in the same population using the same methodology. Therefore, we studied the prevalence of somatic TSHR mutations in TTNs from patients living in iodine-deficient or -sufficient regions in Turkey. DESIGN AND METHODS: We screened 74 TTNs for somatic TSHR mutations. Exons 9 and 10 of the TSHR and 7 and 8 of the Gsalpha were screened by denaturing gradient gel electrophoresis. Determination of X-chromosome inactivation was used for clonality analysis. RESULTS: TSHR mutations were identified in 52 (70.2%) of 74 TTNs. A Gsalpha mutation was identified in one TTN. Three new TSHR mutations were detected (A627V, I640K, I486N). No significant difference between frequencies of TSHR mutations in iodine deficient/sufficient regions was found. The frequency of non-random X-chromosome inactivation was similar in iodine-sufficient or -deficient regions and in TSHR mutation positive or negative hot nodules. CONCLUSIONS: These findings suggest that TTNs in iodine deficient/sufficient areas predominantly arise from aberrant growth of a single cell. Our results suggest that neither the prevalence of TSHR mutations nor that of monoclonal TTNs is related to iodine supply.