Improvement in neck ultrasound report quality following the implementation of European Thyroid Association guidelines for postoperative cervical ultrasound for thyroid cancer follow-up, a prospective population study

Objective

The aim of this study was to prospectively evaluate the quality of postoperative neck ultrasound (POU) for thyroid cancer patients after implementing European Thyroid Association (ETA) guideline-based POU assessment.

Methods

Our analysis involved 672 differentiated thyroid cancer patients. POU report quality was compared between the implementation radiology group (IRG), which implemented ETA guideline-based assessment in 2018, and all non-implementation radiology groups (NIRG). Differences in POU quality were evaluated before and after the implementation of guideline-based assessment. Additionally, we evaluated the ability of serum thyroglobulin (Tg) level <0.2 ng/mL or between 0.21 and 0.99 ng/mL and normal POU lesion status at 1-year follow-up to predict the absence of persistent disease or relapse at 3-year follow-up.

Results

IRG had significantly higher mean utility scores for POU reports of abnormal thyroid bed nodules compared to NIRG (P < 0.001). IRG's POU reports for suspicious nodules and lymph nodes were considered sufficient in 94% and 85% of cases, respectively, compared to 45% and 68% for NIRG. For patients with normal US lesion status and Tg <0.2 ng/mL or Tg 0.21-0.99 ng/mL at 1-year follow-up, the negative predictive values were 96% for both.

Conclusions

Implementation of 2013 ETA POU-reporting guidelines allowed for the provision of high-quality POU reports, which may lead to increased accuracy in assessing the response to treatment and in estimating the risk of recurrence of thyroid cancer and likely reduce unnecessary repeat POU or FNA.

Active Surveillance of Small Metastatic Lymph Nodes as an Alternative to Surgery in Selected Patients with Low-Risk Papillary Thyroid Cancer: A Retrospective Cohort Study

Background: It has been suggested that small metastatic lymph nodes (LNs) detected after initial surgery in patients with differentiated thyroid cancer (DTC) can be managed with active surveillance (AS). However, there is still concern regarding the clinical outcomes of these patients. The main aims of our study were as follows: (1) to assess the frequency of growth and the need of additional treatment in a group of patients with LN recurrences selected for AS, and (2) to determine predictive factors of LN progression. Methods: We retrospectively reviewed 856 clinical records from our DTC patient's database (May 2010 to January 2022). Eighty patients had suspicious cervical LNs on consecutive ultrasound (US) after initial surgery, but we included 50 patients with cytological confirmation of metastatic disease and at least 12 months follow-up. Exclusion criteria were as follows: any LN ≥2 cm or multiple LNs ≥1.5 cm in size, proximity to vital structures, PET-positive disease (standard uptake value ≥5), aggressive histology, and distant metastasis. Patients were followed with thyroglobulin (Tg) and thyroglobulin antibodies measurements on suppressive therapy and neck US every 6-12 months. LN growth was defined as an increase of ≥3 mm in any of its diameters. Results: A total of 50 patients had a median age of 41 years (range, 18-75). Most patients were women (80%) and had classical papillary thyroid cancer (86%). The mean size of the LNs was 10.1 ± 4.4 mm. After a median follow-up of 29 months (range, 12-144), 12 patients (24%) had an increase in size of the metastatic LN, 7 (58%) of whom were surgically removed. None of these seven patients had a structural incomplete response at the end of follow-up. The only variable that predicted an increase in LN size was a rise in Tg levels ≥0.5 ng/mL (p = 0.016). Based on a multivariate analysis, patients with increase in Tg levels ≥0.5 ng/mL had a significantly higher chance of developing LN growth (odds ratio [OR] 16.2 [confidence interval, CI 1.5-120.2], p = 0.020). The median progression-free survival rate was 6.6 years [CI 5.6-9.5]. Conclusion: AS of small LNs could be a feasible alternative to immediate surgery in properly selected patients.

[Analysis of pre-ablative and preoperative thyroglobulin in differentiated thyroid cancer]

BACKGROUND

The measurement of plasma thyroglobulin (Tg) is widely used in the monitoring of differentiated thyroid cancer (CDT). In recent years, its value as a prognostic marker prior to ablation with radioiodine has increased, demonstrating its high negative predictive value. Recent studies indicate that a wide variety of factors could potentially influence pre-ablative Tg values, including residual tumor burden and stimulation modality.

AIM

To relate the value of pre-ablative Tg with the amount of preoperative disease burden, lymph node metastases, treatment, and presence of residual disease.

MATERIAL AND METHODS

Retrospective observational study of 70 patients with CDT treated between 2012 and 2018. The amount of disease burden was defined as the sum of largest diameter of individual tumors in each patient, and as the individually largest tumor per patient and number of metastatic lymph nodes.

RESULTS

A smaller tumor size and absence of remnant tissue was associated with lower Tg values, although the association was not always significant. Furthermore, no significant difference was found between Tg levels measured within or more than 14 days after the surgical procedure. Thus, an early measurement of pTg after surgery would allow an initial therapeutic decision making.

CONCLUSIONS

A statistical association between pre-ablative Tg levels and the amount of preoperative tumor tissue burden was found in some subgroups of patients.

Retrospective Analysis of the Development of Human Thyroglobulin during Pregnancy in Patients with Treated Non-Recurrent Differentiated Thyroid Cancer

Aim: Therapy success in patients with differentiated thyroid cancer (DTC) after thyroidectomy and radioiodine therapy (RIT) is proven by permanent decrease in human thyroglobulin (hTg) to <1 ng/mL. In this retrospective analysis hTg development before, during and after pregnancy were analyzed. Material and methods: A descriptive analysis of hTg courses in 47 women with 57 pregnancies under levothyroxine substitution was performed after treatment of DTC without evidence of residual or recurrent disease. We compared hTg levels before, during and after pregnancies. A median of four measurements were performed during pregnancy. Results: In five out of the 47 patients at least one hTg increase to ≥1.0 ng/mL occurred during pregnancy (P1: 1.1; P2: 1.75; P3: 1.0; P4: 1.1; P5: 1.07 ng/mL). In another three cases an increase to ≥0.5 ng/mL occurred. After delivery, all patients returned to undetectable hTg levels. Human Tg maxima during pregnancy were significantly elevated according to Friedman´s Chi2 and p Holm−Bonferroni. Conclusion: In women with ablative thyroid therapy after DTC, a temporary elevation in hTg levels during pregnancy may occur. The reason therefore remains unclear and requires further investigation.

Screening of 23 candidate genes by next-generation sequencing of patients with permanent congenital hypothyroidism: novel variants in TG, TSHR, DUOX2, FOXE1, and SLC26A7

PURPOSE

To date, many genes have been associated with congenital hypothyroidism (CH). Our aim was to identify the mutational spectrum of 23 causative genes in Turkish patients with permanent CH, including thyroid dysgenesis (TD) and dyshormonogenesis (TDH) cases.

METHODS

A total of 134 patients with permanent CH (130 primary, 4 central) were included. To identify the genetic etiology, we screened 23 candidate genes associated with CH by next-generation sequencing. For confirmation and to detect the status of the specific familial variant in relatives, Sanger sequencing was also performed.

RESULTS

Possible pathogenic variants were found in 5.2% of patients with TD and in 64.0% of the patients with normal-sized thyroid or goiter. In all patients, variants were most frequently found in TSHR, followed by TPO and TG. The same homozygous TSHB variant (c.162 + 5G > A) was identified in four patients with central CH. In addition, we detected novel variants in the TSHR, TG, SLC26A7, FOXE1, and DUOX2.

CONCLUSION

Genetic causes were determined in the majority of CH patients with TDH, however, despite advances in genetics, we were unable to identify the genetic etiology of most CH patients with TD, suggesting the effect of unknown genes or environmental factors. The previous studies and our findings suggest that TSHR and TPO mutations is the main genetic defect of CH in the Turkish population.

Impact of Thyroid Tissue Status on the Cut-Off Value of Lymph Node Fine-Needle Aspiration Thyroglobulin Measurements in Papillary Thyroid Cancer

Objective: To study the optimal cut-off value of thyroglobulin measurement in a fine-needle aspiration (FNA-Tg) in diagnosing malignant lymph nodes and benign lymph nodes (LNs) according to the thyroid tissue status.

Methods: A total of 517 LNs were aspirated: 401 preoperative LNs, 42 LNs after subtotal thyroidectomy and 74 suspected LNs after total thyroidectomy. The cut-off value of FNA-Tg was obtained from receiver operating characteristic (ROC) analysis. The cut-off value with the best diagnostic performance was then obtained by comparing different cut-off values from other studies.

Results: LN FNA-Tg levels differed between preoperative and total thyroid disease (p < 0.001) and subtotal thyroidectomy and total thyroidectomy (p = 0.03), but not between preoperative and subtotal thyroidectomy (p = 1.00). Accordingly, those 443 LNs with preoperative and subtotal thyroidectomy were compared to those 74 without thyroid tissue. The optimal cut-off value in thyroid tissue group was 19.4 ng/ml and the area under the ROC curve (AUC) was 0.95 (95% CI 0.92–0.97). The optimal cut-off value in thyroid tissue absence group was 1.2 ng/ml and the AUC was 0.93 (0.85–0.98). After the analysis and comparison of multiple cut-off values, the optimal diagnostic performance was still found to be 19.4 ng/ml and 1.2 ng/ml.

Conclusion: The influential factors of FNA-Tg are still controversial, and the optimal cut-off value of FNA-Tg can be determined based on the presence or absence of thyroid tissue. FNA-Tg can be used as an important auxiliary method for diagnosing cervical metastatic LNs of thyroid cancer.

Biotin Interference in Assays for Thyroid Hormones, Thyrotropin and Thyroglobulin

Background: Biotin has been reported to interfere with several commonly used laboratory assays resulting in misleading values and possible erroneous diagnosis and treatment. This report describes a prospective study of possible biotin interference in thyroid-related laboratory assays, with a comparison of different commonly used assay platforms. Materials and Methods: Thirteen adult subjects (mean age 45 ± 13 years old) were administered biotin 10 mg/day for eight days. Blood specimens were collected at three time points on day 1 and on day 8 (baseline, two, and five hours after biotin ingestion). Thyrotropin (TSH), free triiodothyronine (fT3), free thyroxine (fT4), total triiodothyronine (TT3), total thyroxine (TT4), thyroxine binding globulin (TBG), and thyroglobulin (Tg) levels were analyzed with four different platforms: Abbott Architect, Roche Cobas 6000, Siemens IMMULITE 2000, and liquid chromatography with tandem mass spectrometry (LC-MS/MS). TSH, fT3, fT4, TT3, and TT4 were measured with Abbott Architect and Roche Cobas 6000. fT3, fT4, TT3, and TT4 were also measured by LC-MS/MS. Tg was measured by Siemens IMMULITE 2000. TBG was assessed with Siemens IMMULITE 2000. Results: Significant changes in TSH, fT4, and TT3 measurements were observed after biotin exposure when the Roche Cobas 6000 platform was used. Biotin intake resulted in a falsely lower Tg level when measurements were performed with Siemens IMMULITE 2000. At the time points examined, maximal biotin interference was observed two hours after biotin exposure both on day 1 and day 8. Conclusions: A daily dose of 10 mg was shown to interfere with specific assays for TSH, fT4, TT3, and Tg. Physicians must be aware of the potential risk of erroneous test results in subjects taking biotin supplements. Altered test results for TSH and Tg can be particularly problematic in patients requiring careful titration of levothyroxine therapy such as those with thyroid cancer.

CYFRA21-1/TG ratio as an accurate risk factor to predict eye metastasis in nasopharyngeal carcinoma: A STROBE-compliant article

Nasopharyngeal carcinoma (NPC) has a distinctive geographical distribution in China, especially southern China. There are several risk factors for NPC, such as Epstein-Barr virus, genetics, and environmental exposures. Although the incidence of eye metastasis (EM) is lower than metastasis in other body parts, it often indicates poor prognosis.We assessed several serum biomarkers for their ability to predict EM in NPC. Patients with NPC were selected (n = 963), and were separated into two groups, EM and no eye metastasis. Ten factors were analyzed in both groups including triglyceride (TG), high-density lipoprotein, low-density lipoprotein, alkaline phosphatase, alpha fetoprotein, carbohydrate antigen-199, cancer antigen-153, apolipoproteins AI, apolipoprotein B, and cytokeratin fragment 19 (CYFRA21-1). Independent t tests, binary logistic regression, and receiver operating characteristic curves were used to assess the data.The EM group had significantly higher CYFRA21-1 and lower TG compared with the no eye metastasis group. Areas under the curve for CYFRA21-1, TG and CYFRA21-1/TG were 0.966, 0.771, and 0.976, respectively. The corresponding cut-off values were 12.12 ng/ml, 0.41 mmol/L, and 13.5. The sensitivity and specificity of CYFRA21-1/TG were 100% and 92.2%, respectively.The increased ratio of CYFRA21-1 to TG can be an accurate method to detect EM in patients with NPC.

Low intake of iodized salt and iodine containing supplements among pregnant women with apparently insufficient iodine status - time to change policy?

BACKGROUND

Iodine is an essential nutrient for human health throughout the life cycle, especially during early stages of intrauterine life and infancy, to ensure adequate neurocognitive development. The growing global reliance on desalinated iodine-diluted water raises the specter of increased iodine deficiency in several regions. The case of Israel may be instructive for exploring the link between iodine status and habitual iodine intake in the setting of extensive national reliance on desalinated water. The aim of this study was to explore the relationship between iodine intake, including iodized salt and iodine-containing supplements intake, and iodine status among pregnant women residing in a sub-district of Israel that is highly reliant on desalinated iodine-diluted water.

METHODS

A total of 134 consecutive pregnant women were recruited on a voluntary basis from the obstetrics department of the Barzilai University Medical Center during 2018. Blood was drawn from participants to determine levels of serum thyrotropin (TSH), thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TgAb) and thyroglobulin (Tg). An iodine food frequency questionnaire (sIFFQ) was used to assess iodine intake from food, IS and ICS. A questionnaire was used to collect data on demographic and health characteristics.

RESULTS

A total of 105 pregnant women without known or reported thyroid disease were included in the study. Elevated Tg values (≥ 13 μg/L), were found among 67% of participants, indicating insufficient iodine status. The estimated iodine intake (median, mean ± SD 189, 187 ± 106 μg/d by sIFFQ) was lower than the levels recommended by the World Health Organization and the Institute of Medicine (250 vs. 220 μg/day respectively). The prevalence of iodized salt intake and iodine containing supplement intake were 4 and 52% (respectively). Values of Tg > 13 μg/L were inversely associated with compliance with World Health Organization and Institute of Medicine recommendations.

CONCLUSIONS

While the Israeli Ministry of Health has recommended the intake of iodized salt and iodine containing supplements, this is apparently insufficient for achieving optimal iodine status among Israeli pregnant women. The evidence of highly prevalent probable iodine deficiency in a sample of pregnant women suggests an urgent need for a national policy of iodized salt regulation, as well as guidelines to promote iodine containing supplements and adherence to them by caregivers. In addition, studies similar to this one should be undertaken in additional countries reliant on desalinated iodine-diluted water to further assess the impact of desalinization on maternal iodine status.

Diagnostic value of cytology, thyroglobulin, and combination of them in fine-needle aspiration of metastatic lymph nodes in patients with differentiated thyroid cancer: A systematic review and network meta-analysis

BACKGROUND

To investigate the diagnostic performance of cytology (fine-needle aspiration cytology [FNAC]), thyroglobulin (fine-needle aspiration thyroglobulin [FNA-Tg]), and combination of them in the washout of fine-needle aspiration for those patients who have suspicious metastatic lymph nodes of differentiated thyroid cancer.

METHODS

Databases, including PubMed, EMbase, Web of Science and Cochrane Library were searched up to June 2019. The quality assessment of diagnostic accuracy scale-2 was used to conduct quality assessments, and publication bias was evaluated using the Deeks funnel plot. STATA version 14.0 was used to perform the meta-analysis.

RESULTS

A total of 2257 patients with 2786 samples of suspicious metastatic lymph nodes of differentiated thyroid cancer were included in the meta-analysis. The results showed that the diagnostic value for detecting lymph node metastasis of differentiated thyroid cancer was as follows: combination of FNAC and FNA-Tg > FNA-Tg > FNAC. All differences of superiority among them are statistically significant. The sensitivity of the combination was 0.968 (95% confidence interval [CI]: 0.942-0.983), the specificity was 0.932 (95% CI: 0.856-0.969), the diagnostic score was 6.036 (95% CI: 4.892-7.181), the diagnostic odds ratio was 418.424 (95% CI: 133.167-1314.729), and the score of summary receiver operating characteristic was 0.99 (95% CI: 0.97-0.99).

CONCLUSIONS

The combination of FNAC and FNA-Tg is an excellent procedure in diagnosis of lymph nodes metastasis of patients with differentiated thyroid cancer, which should be highly recommended.

Surveillance of patients with differentiated thyroid cancer and indeterminate response: a longitudinal study on basal thyroglobulin trend

PURPOSE

This is a longitudinal study of retrospective data aimed at verifying whether repeated measurements of serum non-stimulated thyroglobulin (Tg) allow the prediction of persistent disease in patients with differentiated thyroid cancer (DTC) and indeterminate response.

METHODS

We examined 145 DTC patients with indeterminate response to therapy followed up for a median time of 68 months. Tg measurements and neck ultrasound (US) were performed every 6-12 months. The changes over time of repeated measurements of basal Tg were analyzed through the multilevel linear regression.

RESULTS

Seventy (48.3%) out of 145 patients spontaneously achieved an excellent response, while persistent indeterminate response was observed in 62 (42.7%) patients. The remaining 13 (9.0%) patients had progression: 3/13 with biochemical disease and 10/13 with structural disease. Tg steadily increased in patients with progressive disease (mean percentage change + 27.1% at each follow-up visit), while Tg decreased in patients without any evidence of progression (mean percentage change - 8.8%). This different trend between the two groups was not related to either different values of median TSH at baseline (0.32 vs 0.28 mIU/l, respectively) or to different trend of TSH during follow-up (p = 0.76). Basal Tg values did not increase in three out of ten patients with structural disease that was identified by neck US.

CONCLUSIONS

The importance of the study is that, in DTC patients with indeterminate response, rising values of unstimulated Tg, independently from the basal levels, may be useful to identify patients with progressive disease. These results are also useful to avoid unnecessary TSH stimulation.

Serum thyroglobulin elevation after needle aspiration of the lymph nodes: the predictive value for detecting metastasis in papillary thyroid cancer patients - a pilot study

Ultrasonography (USG)-guided fine needle aspiration (FNA) is widely used for diagnosis of lymph node (LN) metastasis in papillary thyroid cancer (PTC). However, FNA cytology sometimes shows inconclusive results. Recently, the measurement of thyroglobulin (Tg) in FNA washout fluid (aspirate-Tg) has been widely adopted, but there are some difficulties in the preparation of the sample and standardization of the procedure. Here, we examined serum Tg after FNA as a new predictive marker for LN metastasis of PTC. We performed USG-guided FNA cytology and examined aspirate-Tg in PTC patients showing suspicious metastatic LNs during follow-up. We measured baseline serum thyroid stimulating hormone (TSH), Tg, and Tg antibody levels before FNA, and serum Tg level within an hour after FNA. We defined aspirate-Tg level above 0.9 ng/mL as positive, and a 30% increase in serum Tg level after FNA compared to the baseline as elevation of serum Tg. Twenty-two patients were included in our study. Nine patients (40.9%) showed elevation of Tg level after FNA, and the mean value of Tg elevation was 24.8 ± 48.0 ng/mL. Among these 9 patients, 8 were diagnosed with PTC and 1 patient showed cellular atypia on cytopathology. All these patients showed positive aspirate-Tg. Thirteen patients (59.1%) did not show elevation of Tg level after FNA. Among these patients, 2 had PTC, 2 had cellular atypia, and 9 yielded negative results for malignancy on cytopathology. Elevation of serum Tg level after FNA might have a diagnostic role for predicting LN metastasis of PTC.

Cervical Lymph Node Fine-Needle Aspiration and Needle-Wash Thyroglobulin Reflex Test for Papillary Thyroid Carcinoma

Fine-needle aspiration (FNA) cytology coupled with needle-wash thyroglobulin (FNA-Tg) testing is recommended for cervical lymph node (LN) biopsies in patients with a history of papillary thyroid carcinoma (PTC). However, the procedure has not been standardized with the assay for FNA-Tg testing. A standard operating procedure (SOP) has been generated at our facility for cervical LN FNAs with Tg reflex testing on patients with a history of PTC. The procedure requires FNA cytology to be reviewed first, and all cases not positive for PTC are reflexed for FNA-Tg testing with the Beckman Access thyroglobulin assay. The thyroglobulin cutoff value is ≤ 1.0 ng/mL. From 2016 to 2017, 117 patients, including 71 women and 46 men, were identified as having a history of PTC. Patients' clinical characteristics were collected from medical records. A total of 143 LN biopsies were investigated for these patients. The results show that four out of 11 (36.4%) non-diagnostic LNs and five out of five (100%) atypical/suspicious LNs tested positive for FNA-Tg. Among these nine patients with positive thyroglobulin testing, LN metastases were proven histologically for all nine patients, and two patients were treated with LN ablation. Out of 68 LNs positive for PTC, three had FNA-Tg results. FNA-Tg testing was ordered for unknown reasons on two positive LNs (> 5000 ng/mL thyroglobulin) from one patient. The third LN was tested due to non-classic morphology, and the result was less than the cutoff value. Three patients with negative LN biopsies were tested to have elevated (> 1.0 ng/mL) thyroglobulin levels. One patient (FNA-Tg ng/mL) was proven to have multiple metastatic LNs through follow-up surgery. However, no positive LN was identified for the other two patients who had FNA-Tg level of 4.1 ng/mL and 37 ng/mL respectively. This is likely due to contamination, as these two patients had intact thyroids. In our practice, the FNA-Tg test is a very useful adjunct test to LN FNA specimens with a non-positive diagnosis in patients with a history of PTC. Furthermore, FNA-Tg testing increases diagnostic sensitivity among non-diagnostic and atypical/suspicious LNs. However, FNA-Tg testing should not substitute conventional cytology due to the following reasons: (1) false-negative thyroglobulin lab results; (2) PTC with loss of thyroglobulin expression; (3) LN metastasis from other origins; and (4) false-positive thyroglobulin testing due to blood contamination in patients who are not completely athyrotic.

Multicentre clinical evaluation of the new highly sensitive Elecsys® thyroglobulin II assay in patients with differentiated thyroid carcinoma

OBJECTIVE

A highly sensitive thyroglobulin assay (Elecsys® Tg II, Roche Diagnostics, Penzberg, Germany) has become available for monitoring patients with differentiated thyroid cancer (DTC). Here, we evaluated the clinical performance of Elecsys® Tg II assay in a multicentre patients series and compare it with the established Access® Tg assay (Beckman Coulter, Brea, CA, USA).

DESIGN

Retrospective analysis on prospectively selected patients in four thyroid cancer referral centres with uniform DTC management.

PARTICIPANTS

All DTC cases diagnosed, treated and followed up in four tertiary referral centres for thyroid cancer since January 2005 (n = 1456) were retrieved, and predefined selection criteria were applied to prevent relevant enrolment biases. A series of 204 patients was finally selected for this study.

MEASUREMENTS

Samples had been stored at -80°C. Tg was measured by fully automated immunometric Elecsys® Tg II and Access® Tg assays in a centralized laboratory.

RESULTS

Two hundred and four DTC were finally included. Of these, 10.8% had structural recurrence (sREC), and 81.4% showed no evidence of disease (NED) at the end of follow-up. There was a significant analytical bias between methods that cannot be used interchangeably. Using ROC curve analysis, the best basal and rhTSH-stimulated Tg cut-offs to detect sREC were 0.41 μg/L and 1.82 μg/L for Elecsys® and 0.36 μg/L and 1.62 μg/L for Access® assay, respectively. Using Cox proportional hazard regression, Tg was the only independent predictor of cancer relapse.

CONCLUSIONS

Using appropriate assay-specific cut-offs, the clinical performance of the Elecsys® Tg II assay was comparable to that provided by the well-established Access® Tg assay.

Rare Manifestations of Anaplastic Thyroid Carcinoma: the Role of BRAF Mutation Analysis

Anaplastic thyroid carcinoma (ATC) is difficult to distinguish from other cancers, especially when its pathological features are atypical for ATC or when the tumor is totally undifferentiated and occurs after a considerable lapse of time, in an area remote from the original site of the tumor. Here, we present two patients (68-year-old man and 56-year-old woman) with rare manifestations of ATC, which were initially thought to be other malignancies. Immunohistochemical tests, using various markers, failed to provide information about the origin of these tumors. However, both patients had a history of papillary thyroid carcinoma (PTC) from several years ago and BRAF mutations were observed in the undifferentiated tumors, as well as in the previous PTCs. Therefore, we could make a diagnosis of ATC derived from PTC. As such, BRAF mutation analysis may serve as a useful tool for ATC diagnosis in challenging ATC cases.

Thyroid Cancer: Ultrasound Imaging and Fine-Needle Aspiration Biopsy

Ultrasound is critical in detection, diagnosis, and management of thyroid nodules. Ultrasound detection of regional nodal metastatic disease is based on abnormal nodal morphology rather than size and is critical to initial surgical and long-term management of thyroid cancer. Fine-needle aspiration biopsy is the gold standard for malignancy diagnosis in thyroid cancer. Thyroglobulin assay of nodal aspirates improves accuracy in diagnosis of metastases. Reporting lexicons assign risk levels to thyroid nodules with the goal of improving and standardizing patient management. Surveillance ultrasound in papillary microcarcinomas is being evaluated and compared with surgical management.

Biochemical Testing in Thyroid Disorders

This article summarizes the main principles for the appropriate use of laboratory testing in the diagnosis and management of thyroid disorders, as well as controversies that have arisen in association with some of these biochemical tests. To place a test in perspective, its sensitivity and accuracy should be taken into account. Ordering the correct laboratory tests facilitates the early diagnosis of a thyroid disorder and allows for timely and appropriate treatment. This article focuses on a comprehensive update regarding thyroid-stimulating hormone, thyroxine/triiodothyronine, thyroid autoantibodies, thyroglobulin, and calcitonin. Clinical uses of these biochemical tests are outlined.

Binding of thyroglobulin (Tg) to the low-density lipoprotein receptor-associated protein (RAP) during the biosynthetic pathway prevents premature Tg interactions with sortilin

OBJECTIVE

Sortilin, a Vps10p family member, is expressed by thyroid epithelial cells (TEC), where it binds to internalized thyroglobulin (Tg) molecules. Premature binding of Tg to sortilin during biosynthesis may cause intracellular retention of Tg. Such a premature interaction may be prevented by one or more inhibitor/s. Because both sortilin and Tg bind to the low-density lipoprotein receptor-associated protein (RAP), we investigated whether RAP serves such a function.

METHODS

Immunofluorescence staining for sortilin, Tg, and RAP was performed in FRTL-5 cells. Co-immunoprecipitation experiments were performed in extracts from FRTL-5 or COS-7 cells, the former co-transfected with Tg and/or RAP and/or sortilin, or in thyroid extracts from RAP KO mice.

RESULTS

Tg and sortilin did not co-localize in FRTL-5 cells following inhibition of protein synthesis, suggesting that newly synthesized, endogenous sortilin and Tg do not interact, in confirmation of which an anti-sortilin antibody did not co-precipitate Tg in FRTL-5 cells. In contrast, Tg co-localized with RAP in FRTL-5 cells. Co-immunoprecipitation of Tg with an anti-sortilin antibody in COS-7 cells transfected with sortilin and Tg was abolished when cells were co-transfected with RAP, indicating that RAP prevents binding of Tg to sortilin during biosynthesis, in confirmation of which an anti-sortilin antibody co-precipitated Tg in thyroid extracts from RAP KO mice to a greater extent than in thyroid extracts from WT mice.

CONCLUSIONS

Tg does not bind prematurely to sortilin because of its interaction with RAP during protein biosynthesis. These findings add new information to the knowledge of thyroid physiology.

Effects of sample storage and diluents in the reliability of thyroglobulin measurement in the washout of fine needle aspirates

OBJECTIVE

To evaluate two variables affecting Thyroglobulin stability in the washout of fine needle aspiration biopsies of thyroid nodules and metastatic lymph nodes.

MATERIALS AND METHODS

Thyroglobulin stability after storage at -20 °C up to 14 days was studied in washout performed with normal saline solution and further dilutions with normal saline solution from five metastatic thyroid nodes and six benign thyroid nodules. We also studied thyroglobulin stability in diluents compared with normal saline solution: 4% bovine serum albumin in normal saline solution and diluents free from thyroglobulin or Calcitonin or parathyroid hormone in paired and simultaneous thyroglobulin measurements of washout dilutions from 5/6 benign thyroid nodules and 2/5 metastatic lymph nodes. Thyroglobulin and Thyroglobulin antibodies were measured by a chemiluminescent assay. Positive samples with thyroglobulin antibodies in serum and/or washout were excluded.

RESULTS

Thyroglobulin decreased with storage in washout or dilutions of washout performed in normal saline solution (p < 0.05). Lower thyroglobulin concentrations, close to the commonly used cut-off (1.1 ng/mL), showed the highest decrease as soon as after 1 day of storage. Diluents other than normal saline solution stabilized thyroglobulin in dilutions of all washout.

CONCLUSIONS

The results suggest that the reliability of thyroglobulin measurements in washout of fine needle aspirates could be preserved by immediate measure of thyroglobulin or the use of stabilizing diluents to perform washout.

[Usefulness and Limitation of Thyroglobulin Measurement in Fine Needle Aspirates (FNA-Tg) for Diagnosis of Neck Lymph Node Metastasis from Thyroid Carcinoma]

BACKGROUND

Preoperative diagnosis of lymph node metastasis from thyroid carcinoma is usually confirmed by using fine needle aspiration cytology (FNAC) when thyroid carcinoma is suspected based on the clinical findings. However, the result of FNAC sometimes leads to a false negative, especially in cases of hypocellular lesions such as metastases with cystic change. Thyroglobulin measurement in fine needle aspirates (FNA-Tg) has been shown to be a useful technique to detect the protein specifically secreted by thyroid follicular cells. Elevated FNA-Tg levels in an extra-thyroidal lesion means that the lesion comprises thyroid-originated tissue, most of which suggests the metastasis from thyroid carcinoma. Thus, FNA-Tg is expected to improve the sensitivity of FNAC for the aforementioned purpose.

PATIENTS AND METHODS

From 2008 to 2012, 49 extra-thyroidal lesions from 43 patients with thyroid carcinoma were examined using both FNAC and FNA-Tg, followed by surgical resection with a histopathological diagnosis. The results were retrospectively reviewed and analyzed.

RESULTS

Among 49 lesions, 47 were metastatic lymph nodes from thyroid carcinoma (46 papillary carcinoma and one follicular carcinoma), one was a metastatic lymph node from submandibular gland adenocarcinoma, and one was an ectopic thyroid gland. In the 47 cases of thyroid carcinoma, the sensitivity of FNAC was 57.4% (27/47), whereas that of FNA-Tg was 76.6% (36/47). When both methods were combined, the sensitivity increased to 93.6% (44/47). Metastasis from submandibular gland adenocarcinoma was considered to be an example of a false positive from FNAC, whereas an ectopic thyroid gland was an FNA-Tg false positive. Three lesions were negative for both FNAC and FNA-Tg, although metastases were suspected by imaging studies and confirmed by histopathological diagnosis, which were consistent with examples of a false negative from both FNAC and FNA-Tg findings.

CONCLUSIONS

FNAC reflects whether the lesion has malignant cells, whereas FNA-Tg reflects whether the lesion has thyroid-originated tissue that specifically secrets thyroglobulin. Therefore, FNAC and FNA-Tg are considered to be complementary to each other for the preoperative diagnosis of lymph node metastasis from thyroid carcinoma. FNA-Tg was validated to improve the preoperative diagnostic sensitivity especially when combined with FNAC, however, it is attended with the possibility of a false positive or negative finding, which requires caution in interpretation of the findings.

Type of fish consumed and thyroid autoimmunity in pregnancy and postpartum

Fish consumption or supplementation with omega-3 fatty acids was reported to cure and/or prevent autoimmune and nonautoimmune disorders. Serum positivity for thyroid autoantibodies is a predictive marker of postpartum thyroiditis and postpartum depression. We hypothesized that stable consumption of the omega-3-rich oily fish was associated with a more favorable profile of serum thyroid antibodies throughout pregnancy and early postpartum compared with stable consumption of swordfish, a predator that concentrates pollutants. We prospectively measured serum thyroglobulin antibodies and thyroperoxidase antibodies in pregnancy (first, second trimesters) and postpartum (day 4), in 236 thyroid disease-free, nonsmoker Caucasian women with stable dietary habits. We did not measure thyroid autoantibodies prior to pregnancy. Women were divided into groups A (n = 48; swordfish), B (n = 52; oily fish), C (n = 68; swordfish + other fish, not necessarily oily fish), and D (n = 68; fish other than swordfish and oily fish). Major endpoints were positivity rates and serum concentrations of the two autoantibodies. We resorted to previous studies for the estimated content of fatty acids and microelements in the consumed fish. Positivity rates and serum concentrations of both antibodies were the greatest in group A and the lowest in group B (P < 0.001 and P < 0.05 to < 0.001, respectively). Relationship between monthly fish consumption and serum concentrations of either antibody was direct in group A but inverse in group B. The estimated content of omega-3 fatty acids in fish consumed by group B was the greatest (P < 0.001 vs. any other group). These data reinforce recommendations that pregnant women should avoid consuming swordfish and indicate consumption of oily fish as a favorable alternative. Because thyroid autoantibodies are markers of autoimmune-related postpartum problems, our data suggest a dietary prophylaxis of such problems.

Macrocalcitonin Is a Novel Pitfall in the Routine of Serum Calcitonin Immunoassay

CONTEXT

Calcitonin (CT) is a sensitive marker of medullary thyroid carcinoma (MTC) and is used for primary diagnosis and follow-up after thyroidectomy. However, persistently elevated CT is observed even after complete surgical removal without evidence of a recurrent or persistent tumor.

OBJECTIVE

To investigate the presence of assay interference in the serum CT of MTC patients who are apparently without a structural disease.

PATIENTS AND METHODS

We studied three index MTC cases for CT assay interference and 14 patients with metastatic MTC. The CT level was measured using an immunofluorometric assay. Screening for assay interference was performed by determination of CT levels before and after serum treatment with polyethylene glycol. Additionally, samples were analyzed by chromatography on ultra-performance liquid chromatography and protein A-Sepharose.

RESULTS

Patients with biochemical and structural disease showed CT mean recovery of 84.1% after polyethylene glycol treatment, whereas patients suspected of interference showed recovery from 2-7%. The elution profile on UPLC showed that the immunometric CT from these three patients behaved like a high molecular mass aggregate (>300 kDa). Additionally, when these samples were applied to the protein A-Sepharose, CT immunoreactivity was retained on the column and was only released after lowering the pH.

CONCLUSIONS

For the first time, our results show the presence of a novel pitfall in the CT immunoassay: "macrocalcitonin." Its etiology, frequency, and meaning remain to be defined, but its recognition is of interest and can help clinicians avoid unnecessary diagnostic investigations and treatment during the follow-up of MTC.

Midkine concentrations in fine-needle aspiration of benign and malignant thyroid nodules

CONTEXT

The primary preoperative method for distinguishing malignant from benign thyroid nodules is fine-needle aspiration (FNA) cytology, but it is frequently inconclusive. Midkine (MDK) is a heparin-binding growth factor, which is overexpressed in papillary thyroid carcinoma (PTC).

OBJECTIVE

We measured MDK concentrations in FNA samples from benign and malignant thyroid nodules to explore the possibility that MDK measurement might aid in the evaluation of thyroid nodules.

DESIGN

35 subjects underwent preoperative FNA of 45 thyroid nodules, followed by thyroidectomy, providing a histological diagnosis. FNA needle contents were first expressed for cytology, and then, the needle was washed with buffer for immunoassay. In 46 subjects without preoperative FNA samples, FNA was performed ex vivo on 62 nodules within surgically excised thyroid tissue.

MEASUREMENTS

MDK was measured using a high-sensitivity sandwich ELISA and normalized to thyroglobulin (Tg) concentration in the sample to adjust for tissue content in the aspirate.

RESULTS

The MDK/Tg ratio was higher in 18 PTCs than in 87 benign nodules (204 ± 106 vs 1·2 ± 0·3 ng/mg, mean ± SEM, P < 0·001). Using a threshold of 10 ng/mg, the sensitivity and specificity of the MDK/Tg ratio for diagnosis of PTC were 67% and 99%, respectively. All follicular variant PTCs had a MDK/Tg ratio <10 ng/mg.

CONCLUSIONS

The findings indicate that, in FNA samples, the MDK/Tg ratio in PTC is greater than in benign thyroid nodules, raising the possibility that this approach might provide adjunctive diagnostic or prognostic information to complement existing approaches.

Cytologic Features and Immunocytochemical Profiles of Malignant Effusions with Metastatic Papillary Thyroid Carcinoma: A Case Series from a Single Institution

OBJECTIVE

Malignant effusions due to papillary thyroid carcinoma (PTC) are rare, but portend a poor prognosis. PTC metastases, although rare, most frequently occur in the lungs and bone. Therefore, differentiating thyroid etiology of malignant effusions from other sites becomes clinically significant in patient management. This study examines morphologic and immunocytochemical findings in 5 cases of malignant effusions with PTC involvement.

STUDY DESIGN

The electronic database at the University of Michigan was searched from January 1, 1995 to December 31, 2014 for malignant pleural effusions with PTC involvement. Clinicopathologic data were obtained from electronic medical records. Cytologic slides were reviewed.

RESULTS

Five cases of malignant effusions due to PTC were identified. Characteristic cytologic features of PTC, including ovoid nuclei, irregular nuclear contours, and psammomatous calcifications, were seen. However, the predominant cytologic feature observed was moderate amounts of delicate to vacuolated cytoplasm within the tumor cells. A review of immunocytochemistry demonstrated that all 5 cases showed patchy to diffuse TTF-1 positivity and diffuse positivity for Pax-8. Thyroglobulin only showed focal to patchy positivity in 3 of 5 cases.

CONCLUSION

Given the morphologic features found in our case series, an immunocytochemical workup for the evaluation of involvement of an effusion by a thyroid primary is crucial for accurate diagnosis and appropriate clinical treatment.

Thyroglobulin (Tg) Testing Revisited: Tg Assays, TgAb Assays, and Correlation of Results With Clinical Outcomes

CONTEXT

Measurement of thyroglobulin (Tg) by mass spectrometry (Tg-MS) is emerging as a tool for accurate Tg quantification in patients with anti-Tg autoantibodies (TgAbs).

OBJECTIVE

The objective of the study was to perform analytical and clinical evaluations of two Tg-MS assays in comparison with immunometric Tg assays (Tg-IAs) and Tg RIAs (Tg-RIAs) in a cohort of thyroid cancer patients.

METHODS

A total of 589 samples from 495 patients, 243 TgAb-/252 TgAb+, were tested by Beckman, Roche, Siemens-Immulite, and Thermo-Brahms Tg and TgAb assays, two Tg-RIAs, and two Tg-MS assays.

RESULTS

The frequency of TgAb+ was 58%, 41%, 27%, and 39% for Roche, Beckman, Siemens-Immulite, and Thermo-Brahms, respectively. In TgAb- samples, clinical sensitivities and specificities of 100% and 74%-100%, respectively, were observed across all assays. In TgAb+ samples, all Tg-IAs demonstrated assay-dependent Tg underestimation, ranging from 41% to 86%. In TgAb+ samples, the use of a common cutoff (0.5 ng/mL) for the Tg-MS, three Tg-IAs, and the USC-RIA improved the sensitivity for the Tg-MSs and Tg-RIAs when compared with the Tg-IAs. In up to 20% of TgAb+ cases, Tg-IAs failed to detect Tg that was detectable by Tg-MS. In Tg-RIAs false-high biases were observed in TgAb+ samples containing low Tg concentrations.

CONCLUSIONS

Tg-IAs remain the method of choice for Tg quantitation in TgAb- patients. In TgAb+ patients with undetectable Tg by immunometric assay, the Tg-MS will detect Tg in up to 20% additional cases. The Tg-RIA will detect Tg in approximately 35% cases, but a significant proportion of these will be clinical false-positive results. The undetectable Tg-MS seen in approximately 40% of TgAb+ cases in patients with disease need further evaluation.

MiR-346 regulates CD4⁺CXCR5⁺ T cells in the pathogenesis of Graves' disease

Follicular helper T (Tfh) cells are increasingly recognized as participants in various autoimmune diseases, including Graves' disease. Although many transcription factors and cytokines are known to regulate Tfh cells, the role of noncoding RNA in Tfh cells development and function is poorly understood. Twenty-three patients with GD, eleven patients with remitting GD, and twenty-four healthy controls were enrolled in the current study. The interaction of miRNA and target gene was predicted through software analysis and then validated by luciferase assay and Western blot. The levels of miR-346 in circulating CD4(+) T cells and plasma were measured by qRT-PCR. The correlation of miR-346 levels with the percentages of CD4(+)CXCR5(+)T cells and autoantibody levels were also analyzed. Up-regulation of Bcl-6 and down-regulation of miR-346 in GD patients were observed, and miR-346 could inhibit Bcl-6 at both transcriptional and translational levels. Overexpression of miR-346 led to attenuating CD4(+)CXCR5(+) T cells. The abnormal expression of miR-346 restored in GD patients after treatment. A negative correlation between levels of miR-346 and percentages of CD4(+)CXCR5(+) T cells was confirmed in GD patients. Additionally, negative correlations between the levels of miR-346 in circulating CD4(+) T cells and serum concentrations of TR-Ab, TG-Ab, and TPO-Ab were also revealed in GD patients. MiR-346 regulates CD4(+)CXCR5(+) T cells by targeting Bcl-6, a positive regulator of Tfh cells, and might play an important role in the pathogenesis of Graves' disease.

Diagnostic values of thyroglobulin measurement in fine-needle aspiration of lymph nodes in patients with thyroid cancer

We aimed to evaluate the diagnostic performance of measuring the concentration of thyroglobulin (Tg) in the washout fluid of the needle aspiration (FNA-Tg). We performed a systematic search of MEDLINE (inception to October 2013) and EMBASE (inception to October 2013) for English publications using keywords "thyroid", "aspiration", "washout", and "thyroglobulin". All searches were limited to human studies. We included studies of FNA-Tg measurement in the washout fluid rinsed with 1 ml of normal saline. Eight studies including 843 lymph nodes (LNs) were eligible for this study. The pooled sensitivity and specificity of preoperative studies are 0.89 [95 % CI 0.82-0.95], 0.60 [0.49-0.70], and those of postoperative studies are 1.0 [0.83-1.0], 1.0 [0.92-1.0]. To determine best cutoffs from each preoperative and postoperative study, the distance between the point (0, 1) and each observed cutoff values (1-specificity, sensitivity) was calculated, and the distance is minimal when the cutoff value of 32.04 for preoperative studies and of 0.9 for postoperative one are selected. FNA-Tg can be used for both preoperative and postoperative evaluation of LN metastasis. Although the cutoff values for the FNA-Tg has not been standardized, preoperative values of 32.04 ng/ml and postoperative values of 0.9 ng/ml are recommended for identifying neck LN metastasis.

Thyroglobulin level in fine-needle aspirates for preoperative diagnosis of cervical lymph node metastasis in patients with papillary thyroid carcinoma: two different cutoff values according to serum thyroglobulin level

BACKGROUND

Measurement of thyroglobulin (Tg) in the washout fluid of fine-needle aspirates (FNA-Tg) is useful for diagnosis of lymph node (LN) metastasis in papillary thyroid carcinoma (PTC). However, the cutoff value of FNA-Tg in the preoperative state is not defined clearly. This study aimed to evaluate the optimal cutoff value of preoperative FNA-Tg according to serum Tg level.

METHODS

FNA-Tg was measured in 135 PTC patients (160 LNs) for preoperative diagnosis of cervical LN metastasis.

RESULTS

Of the 160 LNs, 119 (74%) were surgically removed and 110 (69%) were diagnosed as malignant. When we adopted a FNA-Tg of 1.0 μg/L as the cutoff value, the sensitivity and specificity were 99% and 76%, respectively. FNA-Tg levels were correlated with serum Tg levels (Pearson's coefficient 0.42, p=0.002) and the FNA-Tg levels of 12 of the 50 benign LNs were above 1.0 μg/L. We classified the LNs into two groups according to serum Tg level regardless of anti-Tg antibody status: a low Tg group (≤1.0 μg/L, n=22, 14%) and a high Tg group (>1.0 μg/L, n=138, 86%). In the low Tg group, the sensitivity and specificity of the FNA-Tg cutoff value of 1.0 μg/L were 93% and 100%, respectively. In the high Tg group, the sensitivity and specificity of the FNA-Tg cutoff value of 19.0 μg/L were 93% and 100%, respectively. A Tg ratio (FNA-Tg level divided by serum Tg level) of 0.5 gave an improved diagnostic performance (sensitivity, 98%; specificity, 98%) in the high Tg group.

CONCLUSIONS

FNA-Tg levels in the preoperative state are affected by serum Tg levels when they exceeded 1.0 μg/L. For the preoperative diagnosis of metastatic cervical LNs, it seems reasonable to employ different cutoff values of FNA-Tg depending on serum Tg levels. We propose the use of an optimal cutoff value of FNA-Tg of 1.0 μg/L in patients with low serum Tg levels and a Tg ratio of 0.5 in those with high serum Tg levels irrespective of thyroglobulin antibody status.

Thyroglobulin in lymph node fine-needle aspiration washout: a systematic review and meta-analysis of diagnostic accuracy

CONTEXT

The thyroglobulin measurement in the needle washout after fine-needle aspiration (FNA) has been reported to increase the sensitivity of FNA in identifying lymph node (LN) metastases from differentiated thyroid cancer (DTC).

OBJECTIVE

The aim of the study was to estimate the diagnostic accuracy of this technique.

DATA SOURCES

To identify eligible studies, we searched electronic databases for original articles in English from 1975 through 2013.

STUDY SELECTION

Studies that enrolled participants with suspicious neck LNs during thyroid nodule workup or thyroid cancer follow-up were included.

DATA EXTRACTION

Working independently, authors used a standard form to extract data. For quality assessment, QUADAS2 guidelines were applied.

DATA SYNTHESIS

Including all the selected studies (24 studies, 2865 LNs) in the pooled analysis, overall sensitivity was 95.0% (95% confidence interval [CI], 93.7-96.0%), specificity was 94.5% (95% CI, 93.2-95.7%), and diagnostic odds ratio (DOR) was 338.91 (95% CI, 164.82-696.88) with significant heterogeneity (inconsistency [I(2)] = 65.7%; heterogeneity, P < .001). Stratifying different populations and including only patients with thyroid gland (410 LNs), pooled sensitivity was 86.2% (95% CI, 80.9-90.5%), specificity was 90.2% (85.1-94.0%), and DOR was 56.621 (22.535-142.26; I(2) = 37.3%; heterogeneity, P = .121). Including only patients after thyroidectomy (1007 LNs), pooled sensitivity was 96.9% (95% CI, 94.9-98.2%), specificity was 94.1% (91.7-96.0%), and DOR was 407.65 (198.67-836.46; I(2) = 0.0%; heterogeneity, P = .673).

CONCLUSIONS

Thyroglobulin measurement in washout from LN FNA has high accuracy in early detection of nodal metastases from DTC. The technique is simple, but a better standardization of criteria for patient selection, analytical methods, and cutoff levels is required.

The effectiveness of recombinant human thyroid-stimulating hormone versus thyroid hormone withdrawal prior to radioiodine remnant ablation in thyroid cancer: a meta-analysis of randomized controlled trials

We evaluated the efficacy of recombinant human thyroid-stimulating hormone (rhTSH) versus thyroid hormone withdrawal (THW) prior to radioiodine remnant ablation (RRA) in thyroid cancer. A systematic search of MEDLINE, EMBASE, the Cochrane Library, and SCOPUS was performed. Randomized controlled trials that compared ablation success between rhTSH and THW at 6 to 12 months following RRA were included in this study. Six trials with a total of 1,660 patients were included. When ablation success was defined as a thyroglobulin (Tg) cutoff of 1 ng/mL (risk ratio, 0.99; 95% confidence interval, 0.96-1.03) or a Tg cutoff of 1 ng/mL plus imaging modality (RR 0.97; 0.90-1.05), the results of rhTSH and THW were similar. There were no significant differences when ablation success was defined as a Tg cutoff of 2 ng/mL (RR 1.03; 0.95-1.11) or a Tg cutoff of 2 ng/mL plus imaging modality (RR 1.02; 0.95-1.09). When a negative (131)I-whole body scan was used solely as the definition of ablation success, the effects of rhTSH and THW were not significantly different (RR 0.97; 0.93-1.02). Therefore, ablation success rates are comparable when RRA is prepared by either rhTSH or THW.

Thyroglobulin as early prognostic marker to predict remission at 18-24 months in differentiated thyroid carcinoma

INTRODUCTION

Thyroglobulin (Tg), the most common marker to determine remission of differentiated thyroid carcinoma (DTC), can take 18 months or longer to be undetectable. We hypothesized that Tg stimulated after surgery and immediately before radioiodine treatment (baseline-stimulated Tg) could be a good predictor of remission at 18-24 months. The aim of this study was to evaluate the role of baseline-stimulated Tg as early prognostic marker of DTC.

PATIENTS AND METHODS

Retrospective study of 133 patients with DTC from 1998 to 2010 (age at diagnosis 47·4 ± 16·8, follow-up 5·09 ± 3·2 years). Initial subset analysis was performed after excluding patients with positive TgAb, who were later included in the second. Baseline-stimulated Tg was divided into tertiles. Multivariate logistic regression analysis included baseline Tg and other known prognostic markers and receiver operating characteristic (ROC) curve to identify the best cut-off level of baseline Tg were performed.

RESULTS

Baseline-stimulated Tg in the highest tertile was the only predictive variable of persistence of disease at 18-24 months in the initial analysis (OR 45·3, P < 0·01). In the second analysis, the predictive variables were baseline-stimulated Tg (OR 39·6, P < 0·001), presence of TgAb (OR 23·4, P < 0·005) and uptake outside of the thyroid bed post-treatment whole body scan (WBS; OR 5·3, P < 0·05) were predictive of persistence of disease. The ROC curve showed that baseline-stimulated Tg below 8·55 μg/l identified 95% of disease-free patients at 18-24 months after initial treatment.

CONCLUSIONS

Baseline-stimulated Tg is a good predictor of remission of disease at 18-24 months after initial treatment and could be a useful marker to stratify risk immediately after surgery.

Examination of an absolute quantity of less than a hundred nanograms of proteins by amino acid analysis

We developed an ultra-sensitive method of amino acid analysis (AAA) for the absolute quantification of less than 100 ng of proteins, in solution or on polyvinylidene difluoride (PVDF) membranes using an oxygen-free chamber for protein hydrolysis. We used a pre-label method with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate for fluorescence detection, ion-pair chromatography with a reversed-phase column, and an ultra-high-pressure high-performance liquid chromatography. We optimized both handling- and instrument-dependent factors for accurate quantification and showed that the least amount of proteins to quantify was determined by handling accuracy rather than instrumental limit for quantification which was 0.6 fmol/amino acid. As a new evaluation method for the handling accuracy, we adopted the protein identification by the obtained amino acid compositions by AAA and the Swiss-Prot database search without the restriction of species. As a result, the least amount of starting material for AAA was 16 ng (0.24 pmol) for a solution of bovine serum albumin (BSA), 33 ng (0.50 pmol) for BSA on a PVDF membrane, and 44 ng (0.15 pmol) for thyroglobulin on a PVDF membrane. These results demonstrate that the ultra-sensitive AAA developed in this study is feasible for absolute quantification of biological significant protein.

Figure

Clinical review: improving the measurement of serum thyroglobulin with mass spectrometry

CONTEXT

Serum thyroglobulin (Tg) measurements are central to the management of patients treated for differentiated thyroid carcinoma. For decades, Tg measurements have relied on methods that are subject to interference by commonly found substances in human serum and plasma, such as Tg autoantibodies. As a result, many patients need additional imaging studies to rule out cancer persistence or recurrence that could be avoided with more sensitive and specific testing methods.

OBJECTIVES

The aims of this review are to: 1) briefly review the interferences common to Tg immunoassays; 2) introduce readers to liquid chromatography-tandem mass spectrometry as a method for quantifying proteins in human serum/plasma; and 3) discuss the potential benefits and limitations of the method in the quantification of serum Tg.

RESULTS

Mass spectrometric methods have traditionally lacked the sensitivity, robustness, and throughput to be useful clinical assays. These methods failed to meet the necessary clinical benchmarks due to the nature of the mass spectrometry workflow and instrumentation. Over the past few years, there have been major advances in reagents, automation, and instrumentation for the quantification of proteins using mass spectrometry. More recently, methods using mass spectrometry to detect and quantify Tg have been developed and are of sufficient quality to be used in the management of patients.

CONCLUSIONS

Novel serum Tg assays that use mass spectrometry may avoid the issue of autoantibody interference and other problems with currently available immunoassays for Tg. Prospective studies are needed to fully understand the potential benefits of novel Tg assays to patients and care providers.

Utility of thyroglobulin measurements in fine-needle aspirates of space occupying lesions in the thyroid bed after thyroid cancer operations

BACKGROUND

Ultrasound, and sometimes cytology, cannot differentiate between recurrent or persistent thyroid cancer and benign forms of space occupying lesions (SOLs) in the thyroid bed, including unsuspected thyroid remnants, that are noted several months to years after thyroidectomy (Tx) for thyroid cancer. The purpose of the present study was to evaluate the hypothesis that measurement of thyroglobulin (Tg) in fine-needle aspirates from these lesions might help differentiate between benign and malignant SOLs in the thyroid bed.

METHODS

We studied 47 lesions in the thyroid bed from 43 patients who, 8-240 months previously, had 43 Txs for thyroid cancer. Eleven patients had a lobectomy and 32 patients had a total Tx. Also, some patients had radioactive iodine (RAI) ablation after their thyroid surgery and some did not. "Recurrence" was defined as the SOL, which was confirmed by cytological or histopathological results. "Benign SOL" was defined as a focal lesion, which was benign or nondiagnostic result on cytology and for which there was no RAI uptake on whole-body scintigraphy with both negative serum Tg and Tg antibodies. Diagnostic performances of fine-needle aspiration cytology (FNAC), FNA-Tg, and combining FNAC with FNA-Tg level were assessed for detection of malignant SOL. The diagnostic performance of FNA-Tg was assessed using three threshold values: 1 ng/mL, 10 ng/mL, and an FNA-Tg/serum-Tg ratio of 1.0.

RESULTS

FNA-Tg level and combining FNA-Tg levels with FNAC had higher sensitivities (100% in all three threshold values) and diagnostic accuracies (91.5%-95.7%) than FNAC alone (sensitivity of 85.3%, accuracy of 89.4%) in all threshold values. In both the RAI ablation and non-RAI ablation groups, the FNA-Tg levels and combining the FNA-Tg levels with FNAC had a higher sensitivity and diagnostic accuracy than FNAC alone with threshold values of 10 ng/mL and FNA-Tg/serum-Tg ratio of 1.0. The non-RAI ablation group did not have a different diagnostic accuracy than the RAI ablation group in all threshold values (p>0.05). FNA-Tg level showed a negative predictive value of 100% in all threshold values, in both the RAI ablation and the non-RAI ablation groups.

CONCLUSIONS

Measurement of Tg levels in the FNA of SOLs in the thyroid bed can be helpful in diagnosing tumor recurrence, because an FNA-Tg level lower than the threshold value has the added value of suggesting a benign lesion rather than tumor recurrence.

Pulmonary metastasis of a papillary thyroid carcinoma and primary lung adenocarcinoma: two coincident carcinomas at the same location

Tumor-to-tumor metastasis is a fairly rare phenomenon. The lung cancers are the most common donors, but are exceedingly rare as recipients. Here we report a case of a lung adenocarcinoma acting as the recipient of papillary thyroid carcinoma, with multiple spreading foci of the two cancers in the lung simultaneously. The morphology and immunohistochemistry (Napsin-A, Thyroglobulin) are very important in differential diagnosis of lung primary adenocarcinoma and metastatic papillary thyroid carcinoma.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2069496615891134.

Thyroglobulin wash testing in the surveillance of patients with thyroid carcinoma: proposal for a reflex test

OBJECTIVE

Fine needle aspiration (FNA) cytology with thyroglobulin wash (TG-W) testing is recommended for follow-up of patients with differentiated thyroid carcinoma (DTC). The goal of this retrospective study was to determine if TG-W results contributed to the management of cases with positive FNA cytology.

STUDY DESIGN

We reviewed data on patients with positive and suspicious cytology results, undergoing lymph node or thyroid bed FNA with TG-W testing as part of the preoperative or follow-up investigation of histologically proven DTC in our institution and from the literature.

RESULTS

Of 30 positive/suspicious lymph node and thyroid bed FNAs in our institution, 22 (73%) had an elevated (>1 ng/ml) TG-W level. Seven of 8 TG-W-negative cases had DTC on follow-up. Of 577 cytology-positive/suspicious FNAs in the literature, 557 (97%) showed TG-W-positive results. Fourteen of 20 TG-W-negative cases had DTC on follow-up. All patients in retrospective and literature review groups with positive and suspicious FNA cytology and available follow-up were treated for recurrent or metastatic disease regardless of TG-W results.

CONCLUSION

Observations of both our and other institutions support a recommendation of reflex FNA TG-W testing only for cases with negative or indeterminate cytology results.

Serum antithyroglobulin antibodies interfere with thyroglobulin detection in fine-needle aspirates of metastatic neck nodes in papillary thyroid carcinoma

CONTEXT

It is recommended to measure thyroglobulin (Tg) levels in the needle washout fluids from fine-needle aspirations (FNAs) in patients with papillary thyroid carcinoma (PTC) who have ultrasonographically suspicious metastatic lymph nodes (LNs). However, it is not clear whether serum anti-Tg antibodies (TgAbs) interfere with the detection of Tg in needle washout fluids from FNAs (FNA-Tg).

OBJECTIVE

The objective of the study was to evaluate the influence of serum TgAbs on FNA-Tg detection.

DESIGN AND SETTINGS

This retrospective observational cohort study enrolled 207 patients with conventional PTC in whom FNA-Tg values had been measured. All patients initially underwent total thyroidectomy and remnant ablation. FNA-Tg levels were measured from ultrasonographically suspicious metastatic LNs of 0.5 cm or greater in the longest diameter.

RESULTS

From 207 patients, 263 LNs were evaluated. Final histopathology was available for 92 LNs, of which 88 (96%) were malignant. FNA-Tg levels were lower in the LNs from serum TgAb-positive patients than in those from TgAb-negative patients (P < 0.001). In four of 13 metastatic LNs from TgAb-positive patients, the FNA-Tg levels were below 10 μg/liter including one in which both FNA-Tg and serum-stimulated Tg levels were below 1 μg/liter and stained positively for Tg in pathology. There was also one malignant LN with negative for FNA-Tg, serum-stimulated Tg, and serum TgAb but that nonetheless stained intensely for Tg. However, there were no malignant LNs with both negative cytology and negative FNA-Tg. A diagnosis based on FNA-Tg had a lower sensitivity and negative predictive value in the TgAb-positive group than in the TgAb-negative group.

CONCLUSION

FNA-Tg measurement is highly reliable in the diagnosis of neck metastases in PTC patients, even in cases of negative-stimulated Tg or positive TgAb. However, high-serum TgAb levels could interfere with FNA-Tg measurements and thereby result in falsely low FNA-Tg levels.

Parathyroid incidentalomas detected during thyroid ultrasonography and effect of chronic thyroiditis on false positive parathyroid lesions

We aimed to determine the prevalence of parathyroid incidentalomas in patients referred for thyroid ultrasonography (US) and investigate the role of chronic thyroiditis on false positive lesions. Patients suspected to have parathyroid lesions during thyroid US were recorded prospectively between August 2009 and January 2010. Patients referred for parathyroid US and patients with known high serum calcium or parathyroid hormone (PTH) levels were excluded. Suspected parathyroid lesions were defined as hypoechoic, homogeneous, solid lesions with regular margins located outside the thyroid lobe, most commonly inferior to the thyroid gland. Thyroid US was performed in 6,528 patients. There were 78 patients (1.19 %) (73 female and 5 male) with suspected parathyroid lesion. The diagnosis of a true parathyroid adenoma was confirmed in 6 (7.69 %) patients. In patients with true adenoma, mean serum calcium, phosphorus, and PTH levels were 10.57 ± 0.48 mg/dl, 3.03 ± 0.52 mg/dl, and 182.91 ± 46.62 pg/ml, respectively. Among 72 patients with false positive parathyroid lesion, antithyroid peroxidase antibody was positive in 50 (69.4 %), antithyroglobulin antibody was positive in 46 (63.9 %), and one of these antibodies were positive in 59 (81.9 %) patients. Also, 46 (63.9 %) of these patients had thyroid dysfunctions (43 hypothyroidism and 3 hyperthyroidism) and 59 (81.9 %) had chronic thyroiditis ultrasonographically. Parathyroid incidentaloma was detected in 0.09 % of patients referred for thyroid US. The presence of clinically or ultrasonographically chronic thyroiditis might cause inadvertent interpretation of a hypoechoic lesion as a parathyroid pathology during thyroid US.

Diagnostic utility of thyroglobulin measurement in the fine needle aspirates from cervical lymph nodes: a case report

Fine needle aspiration cytology (FNAC) is the more accurate diagnostic method for cervical lymph node (CLN) metastasis from differentiated thyroid cancers (DTC). However, FNAC diagnosis of cystic CLN is, in most cases, uninformative due to inadequate cellularity. Recently, thyroglobulin (Tg) detection in FNAC needle washout fluid has been shown to improve the diagnostic accuracy of FNAC, and its routine association with cytology is recommended. We here describe the case of a 20 yr old girl complaining of the recent appearance of palpable non-painful laterocervical nodes in the neck. Ultrasound examination revealed the presence of 3 cystic CLNs and 2 mixed thyroid nodules, with the larger one showing irregular margins. On the latter, and on 2 larger CLNs, FNAC was performed, and both Tg protein and mRNA were determined in the needle washout. The cytological analysis was not diagnostic for the two CLNs, while that of the thyroid nodule reported the presence of colloid and groups of thyrocytes with normal morphology. Both CLNs showed, however, high levels of Tg protein and were positive for Tg mRNA, suggestive of metastatic DTC. Based on these findings, the FNAC analysis was performed on the second smaller thyroid nodule suggesting (Tir4) the presence of PTC. The patient was then subjected to total thyroidectomy with lymph nodes resection of the central and homolateral compartments. The histological diagnosis confirmed the presence of a PTC in the small nodule and metastatic lymph nodes. In conclusion, this case confirms that the cytological diagnosis of cystic lymph nodes is challenging, and that the measurement of Tg protein and/or mRNA in the needle washout may overcome this limitation.

Papillary thyroid microcarcinoma presenting as lymph node metastasis--a diagnostic challenge: case report and systematic review of literature

Papillary thyroid microcarcinomas (PTMCs) have an excellent prognosis, although a few may metastasize to cervical lymph nodes. However, an infiltrated palpable neck node without evidence of thyroid disease at presentation is uncommon. We report a patient with PTMC presenting as a solitary lymph node metastasis without evidence of primary thyroid tumor in thyroid imaging and with inconclusive lymph node fine-needle biopsy (FNB) cytology. In our case, node excision and histological examination set the diagnosis and immunocytochemical staining of the FNB specimens verified it. A systematic review of reported similar cases was performed; relevant diagnostic dilemmas were also summarized. The clinical presentation of this type of papillary carcinoma becomes evident at a relatively younger age and affects almost equally the two genders; the enlarged lymph node is almost exclusively ipsilateral to the primary tumor, which may be unifocal or multifocal and is difficult to detect by thyroid imaging modalities. Lymph node FNB cytology, thyroglobulin (Tg) measurement in the washout liquid of the FNB needle, FNB immunocytochemistry and lymph node excision accompanied by histological examination provide a stepwise diagnostic approach. We conclude that PTMC may present as a lymph node metastasis without evidence of a primary thyroid tumor. In such cases, thyroid malignancy should be suspected and, in the presence of negative or non-diagnostic lymph node FNB cytology, measurement of Tg in the fluid aspirate should be performed.

Usefulness of thyroglobulin measurement in needle washouts of fine-needle aspiration biopsy for the diagnosis of cervical lymph node metastases from papillary thyroid cancer before thyroidectomy

In evaluating cervical lymph node (LN) metastasis from papillary thyroid cancer (PTC), ultrasonography (US)-guided fine-needle aspiration biopsy (FNAB) is very important tool. There were limited number of studies about the diagnostic value of thyroglubion measurement in FNAB (FNAB-Tg) in non-thyroidectomized patients. Therefore, in this study, the authors evaluated the role of FNAB-Tg in diagnosing cervical LN metastases in patients with PTC before thyroidectomy. A total 91 suspicious LNs of 68 patients were undergone US-guided FNAB-Tg and cytology. Any FNAB-Tg concentration above 50 ng/ml considered as positive, irrespective of thyroid gland presence. Based on the final pathology, 49 LNs were positive, and the remaining 42 LNs were negative for metastasis. The sensitivity, specificity, and accuracy of FNAB-Tg in thyroidectomized patients were 80.0, 100.0, and 88.9%, respectively. The diagnostic performance of FNAB-Tg was not compromised by the presence of thyroid gland (sensitivity, specificity and accuracy = 95.0, 90.9 and 93.2%, respectively). FNAB-Tg is useful and simple method for the diagnosis of metastatic cervical LNs from PTC. The diagnostic performance of FNAB-Tg was not compromised by the presence of thyroid gland. Therefore, FNAB-Tg could be performed actively for the LN staging of PTC.

[Blood tests and imaging in thyroid pathology]

Circulating analytes used in the exploration of thyroid function are TSH and free thyroid hormones (FT4 and FT3). TSH is used as first line analysis in diagnosis because a normal value excludes almost always a thyroid dysfunction. However in the follow up of a treatment for hypo- or hyperthyroidism, free hormones are to be determined since TSH reaction is delayed and does not reflect precisely the restoration of euthyroidism. The measurement of anti-thyroperoxidase antibodies (anti-TPO) will show the presence of an autoimmune thyroiditis and that of thyroid stimulating antibodies (TSI) will establish the diagnosis of Graves' disease. The measurement of circulating thyroglobulin has no place in the diagnostic of thyroid dysfunction nor in the evaluation of a goitre but it is now the golden standard in the follow up of patients with a differentiated thyroid cancer after surgery and radioiodine ablation in patients without antithyroglobulin antibodies. Echography is the first line examination to evaluate thyroid morphology. It shows tiny thyroid nodules and gives precious informations on their structure, as well as paremchymatous diffuse abnormalities associated with thyroiditis. Thyroid scintigraphy with 99mTc allows establishing the functional characteristics of thyroid nodules (warm or cold) and to precise the origin of a thyrotoxicosis (autonomous toxic nodule vs Graves-Basedow, sub acute or silent thyroiditis). Whole body scintigraphy is mandatory after radioiodine treatment with 131I in order to visualize possible metastasis and establish their avidity for iodine.

Expression of estrogen and androgen receptors in differentiated thyroid cancer: an additional criterion to assess the patient's risk

Estrogen receptor (ER) and androgen receptor (AR) may be expressed in thyroid tumors, but their prognostic role is controversial. We investigated whether ER and AR expressions could confer a more aggressive phenotype to thyroid tumors. We enrolled 91 patients (13 males and 78 females, mean age 49.3±14.8 years) bearing small (T1 in the 2006 TNM system) differentiated thyroid cancers (DTC). Thirty-eight tumors were incidental histological findings. Using immunohistochemistry, we evaluated ERα, ERβ, and AR expressions in tumors and in its correspondent extra-tumor parenchyma. In tumors, 13 (16.7%) women and one (7.7%) man expressed ERα; 42 (53.8%) women and six (46%) men expressed ERβ; and 16 (20.5%) women and three (23.1%) men expressed AR. In normal thyroid parenchymas, ERβ was expressed in 52 (66.7%) women and nine (69.2%) men, ERα in three (3.8%) women, and AR in 13 (16.7%) women. Compared with normal thyroid parenchyma, tumors gained ERα and lost ERβ expressions. Incidental cancers were more commonly ERα(-) than ERα(+) (47.7 vs 14.3%, P=0.037). Postsurgical serum thyroglobulin was higher in ERα(+) tumors than in the ERα(-) tumors (P=0.04). ERβ(-) tumors showed vascular invasion more frequently than the ERβ(+) tumors (26.2 vs 4.1%, P=0.005). AR(+) tumors showed capsular invasion more frequently than the AR(-) tumors (77.8 vs 46.6%, P=0.014). In conclusion, ERα positivity, ERβ negativity, and AR expressions are associated with a more aggressive phenotype of small T1-DTC. ER and AR expressions may represent an additional criterion in deciding whether to perform radioiodine ablation in these tumors.

Lymphocytic thyroiditis on histology correlates with serum thyroglobulin autoantibodies in patients with papillary thyroid carcinoma: impact on detection of serum thyroglobulin

CONTEXT

Serum thyroglobulin (Tg), the marker of residual tumor in papillary thyroid carcinoma, can be underestimated in patients with Tg autoantibodies (TgAb). TgAb are due to a coexistent lymphocytic thyroiditis (LT) or the papillary thyroid carcinoma per se. TgAb assays are highly discordant.

DESIGN

We evaluated 141 patients with a clinical diagnosis of nodular thyroid disease, 32 of Hashimoto's thyroiditis, and four of Graves' disease, who underwent total thyroidectomy for an associated papillary thyroid carcinoma. Patients were classified as papillary thyroid carcinoma-lymphocytic thyroiditis (PTC-T) and papillary thyroid carcinoma (PTC) according to the presence or absence of LT on histology. Tg was measured before thyroid remnant ablation, when it is expectedly detectable, by an immunometric assay (IMA) and TgAb by three noncompetitive IMA and three competitive radioimmunoassays (RIA). The number of lymphocytes was compared with TgAb concentration.

RESULTS

Seventy-two of 177 patients (40.7%) were classified as PTC-T and 105 (59.3%) as PTC. Although the tumor stage was similar in the two groups, Tg was undetectable in more PTC-T (37 of 72) than PTC (12 of 105) (P < 0.01), and Tg values were lower in the former (0; 0-4.7 ng/ml) (median; 25th to 75th percentiles) than in the latter group (9.7; 2.7-24.2) (P < 0.01). Accordingly, the percent of positive TgAb by the six assays resulted in higher PTC-T (29.2-50.0%) than PTC (1.9-6.7%) (P < 0.01). Among 49 patients with undetectable Tg, TgAb were more frequently positive by IMA (57.1-63.3%) than RIA (30.6-42.9%). The number of lymphocytes correlated with TgAb concentration in all six assays (0.34 < Rho < 0.46) (all P < 0.01).

CONCLUSIONS

In papillary thyroid carcinoma, LT on histology must be carefully searched for because it is frequently associated with TgAb and therefore mistakenly low or undetectable Tg. TgAb can be missed by some assays. In absence of LT, TgAb are rare.

[Diagnostics and treatment of differentiated thyroid cancer using nuclear medicine]

Differentiated thyroid cancer (DTC) is a rare cancer with excellent prognosis for most patients. Primary treatment is surgery. Adjuvant radioiodine is used after surgery and in case of residual radioiodine positive disease. Measurements of serum thyroglobulin levels and neck ultrasound (US) are the primary follow-up procedures. For suspected recurrence, US, computed tomography (CT), radioiodine single photon emission computed tomography/CT, and FDG positron emission tomography/CT will be appropriate choices for restaging and further treatment planning. Multidisciplinary collaboration is crucial for optimal management of patients with DTC.

Micro-immunohistochemistry using a microfluidic probe

A flexible method to extract more high-quality information from tissue sections is critically needed for both drug discovery and clinical pathology. Here, we present micro-immunohistochemistry (μIHC), a method for staining tissue sections at the micrometre scale. Nanolitres of antibody solutions are confined over micrometre-sized areas of tissue sections using a vertical microfluidic probe (vMFP) for their incubation with primary antibodies, the key step in conventional IHC. The vMFP operates several micrometres above the tissue section, can be interactively positioned on it, and even enables the staining of individual cores of tissue microarrays with multiple antigens. μIHC using such a microfluidic probe is preservative of tissue samples and reagents, alleviates antibody cross-reactivity issues, and allows a wide range of staining conditions to be applied on a single tissue section. This method may therefore find broad use in tissue-based diagnostics and in research.