Medullary thyroid cancer diagnosis: An appraisal

High Sensitivity of Fine-Needle Aspiration Calcitonin in Detecting Medullary Thyroid Carcinoma Is Independent of Predefined Decisional Thresholds

The measurement of Calcitonin (Ctn) in fine-needle aspiration (FNA) washout fluids (FNA-Ctn) has demonstrated excellent sensitivity, significantly higher than FNA cytology, in detecting medullary thyroid carcinoma (MTC). However, the absence of a fixed cutoff value for FNA-Ctn poses a limitation. This study aimed to investigate whether the sensitivity of FNA-Ctn in detecting MTC varies with different cutoffs reported in the literature. A single-centre series of MTCs was retrospectively reviewed. The preoperative FNA-Ctn levels were re-evaluated using various thresholds previously reported in the literature, and the corresponding FNA-Ctn sensitivities were compared. Twenty-one MTCs were included (69% women; median age 59 years; median serum Ctn value 86 pg/mL; median MTC major diameter 10 mm). The median FNA-Ctn value was 2000 pg/mL (interquartile range 49-250). MTCs nodules were assessed at high risk (ACR TI-RADS 5) in 50% of cases, while 47.6% were cytologically malignant. Additionally, 42.9% of cases were assessed as stage III according to Union for International Cancer Control staging system (UICC). Serum Ctn was significantly lower in stage I (p = 0.04). FNA-Ctn was positively correlated with serum Ctn (Rho = 0.45; p = 0.04), while ACR TI-RADS assessment with MTC stage (Rho = 0.69; p = 0.003). FNA-Ctn sensitivity ranged from 95% to 100% based on the previously proposed FNA-Ctn cutoffs. The high sensitivity of FNA-Ctn in detecting MTC did not significantly differ when applying the previously proposed cutoffs. Given the absence of a universally applicable FNA-Ctn decisional threshold, institutions should establish their own diagnostic cutoffs. Future guidelines should incorporate these concepts to enhance clinical decision-making and patient outcomes.

Treatment and management of medullary thyroid microcarcinoma: a 10-year retrospective study from a single center

OBJECTIVE

To explore individualized treatment and management methods for medullary thyroid microcarcinoma (MTMC).

METHODS

Clinical data of patients with medullary thyroid carcinoma with a diameter ≤1 cm admitted to the First Affiliated Hospital of Kunming Medical University from June 2013 to June 20× were collected. Combined with different treatment guidelines for medullary thyroid carcinoma, factors affecting lymph node metastasis and postoperative disease status were analyzed.

RESULTS

Twenty-nine patients with MTMC were included in the analysis, including 24 patients who underwent total thyroidectomy, 5 who underwent thyroid gland lobectomy, and 13 who experienced postoperative lymph node metastasis. Multifocal tumor and calcitonin (Ctn) were the influencing factors, while multifocal tumor, Ctn, lymph node metastasis, and AJCC stage affected the dynamic risk stratification of postoperative disease.

CONCLUSION

Calcitonin detection is an important method for detecting MTMC. A tumor diameter ≤1 cm does not indicate that the tumor is in the early stage. The presence of multifocal tumors and Ctn should be used as important indicators for preoperative evaluation. Dynamic stratified risk assessment is critical in postoperative follow-up.

Molecular diagnostic approaches in detecting rearranged during transfection oncogene mutations in multiple endocrine neoplasia type 2

Different types of neuroendocrine cancer, including medullary thyroid cancer (MTC) and thyroid C-cell hyperplasia, are part of multiple endocrine neoplasia type 2 (MEN2). A proto-oncogene mutation of the rearranged during transfection (RET) gene changes the way that receptor tyrosine kinases work. Multiple endocrine neoplasia, a pathological condition, involves these kinases. When the RET protooncogene changes, it can cause endocrine adenomas and hyperplasia to happen at the same time or one after the other. Pheochromocytoma, medullary thyroid carcinoma, and hyperparathyroidism, alone or in combination, are present in MEN2A patients. Some patients may also have skin lichen amyloidosis or Hirschsprung's disease. Patients with MEN2A often present with MTC. MTC is aggressive and has the worst prognosis, as most patients exhibit lymph node metastasis. MTC is one of the important causes of death in patients with MEN2A. RET mutation analysis aids in identifying MEN2A symptoms and monitoring levels of calcium, thyroid hormones, calcitonin, normetanephrine, fractionated metanephrines, and parathyroid hormone. The earlier diagnosis of MTC significantly improves survival and prompts better management of MEN2A. In this editorial, we will discuss the significance of molecular diagnostic approaches in detecting RET oncogene mutations in MEN2A.

The impact of preoperative calcitonin screening on the prognosis of patients with medullary thyroid cancer: a retrospective multicenter cohort study

PURPOSE

There is still controversy in different guidelines regarding the necessity of routine preoperative calcitonin (Ctn) testing in medullary thyroid cancer (MTC). The level of preoperative Ctn may influence the extent of surgery.

METHODS

This retrospective multicenter cohort study involved 149 MTC patients from 6 centers between 2013 to 2023. Clinical characteristics, surgical procedure and clinical outcomes were compared between Ctn-screened and Non-screened group. Kaplan-Meier method was used to estimate recurrence-free survival (RFS) and overall survival (OS).

RESULTS

In total, 127 MTC patients with preoperative Ctn screening and 22 MTC patients without screening were analyzed. MTC patients with preoperative Ctn screening underwent more radical surgical procedures including total thyroidectomy and lymph node dissection, compared to those without screening (84.3% vs. 68.2% and 91.3% vs. 72.7%, respectively). The rate of recurrence and death were lower in the Ctn-screened group (16.1% vs. 36.4%, 0.8% vs. 18.2%, respectively). The survival curve showed a significantly better overall survival in Ctn-screened group than Non-screened group (HR:17.932, 95% CI 1.888-170.294, p-value = 0.001), while no significant difference was observed of RFS between two groups (HR:1.6, 95% CI 0.645-3.966, p-value = 0.307).

CONCLUSION

Preoperative Ctn screening can prompt surgeons choosing more radical initial surgical treatment for MTC patients, potentially leading to better long-term outcomes. Further evaluation of the cost-effectiveness of routine Ctn screening in thyroid nodule patients is warranted.

Theranostics of Thyroid Cancer

Molecular imaging is pivotal in evaluating and managing patients with different thyroid cancer histotypes. The existing, pathology-based, risk stratification systems can be usefully refined, by incorporating tumor-specific molecular and molecular imaging biomarkers with theranostic value, allowing patient-specific treatment decisions. Molecular imaging with different radioactive iodine isotopes (ie, I131, I123, I124) is a central component of differentiated carcinoma (DTC)'s risk stratification while [18F]F-fluorodeoxyglucose ([18F]FDG) PET/CT is interrogated about disease aggressiveness and presence of distant metastases. Moreover, it is particularly useful to assess and risk-stratify patients with radioiodine-refractory DTC, poorly differentiated, and anaplastic thyroid cancers. [18F]F-dihydroxyphenylalanine (6-[18F]FDOPA) PET/CT is the most specific and accurate molecular imaging procedure for patients with medullary thyroid cancer (MTC), a neuroendocrine tumor derived from thyroid C-cells. In addition, [18F]FDG PET/CT can be used in patients with more aggressive clinical or biochemical (ie, serum markers levels and kinetics) MTC phenotypes. In addition to conventional radioiodine therapy for DTC, new redifferentiation strategies are now available to restore uptake in radioiodine-refractory DTC. Moreover, peptide receptor theranostics showed promising results in patients with advanced and metastatic radioiodine-refractory DTC and MTC, respectively. The current appropriate role and future perspectives of molecular imaging and theranostics in thyroid cancer are discussed in our present review.

An old friend, a new insight: Calcitonin measurement in serum and aspiration needle washout fluids significantly increases the early and accurate detection of medullary thyroid cancer

BACKGROUND

The sensitivity of cytological (CY) evaluation after fine-needle aspiration (FNA) for detecting medullary thyroid carcinoma (MTC) is a subject of controversy. The routine use of serum calcitonin (CT) in patients with thyroid nodules is not universally adopted. The authors conducted CT screening of FNA washout fluid (FNA-CT) to address the diagnostic challenges. The objective was to assess the contributions of serum CT, FNA cytology (FNA-CY), and FNA-CT to the diagnosis.

METHODS

Between February 2019 and June 2022 (group 1), the authors prospectively screened the CT of patients with thyroid nodules. Both FNA-CY and FNA-CT were performed for patients with persistently elevated CT values. The sensitivity of FNA-CY, serum CT, and FNA-CT for accurate diagnosis was evaluated. Additionally, the authors retrospectively examined data from patients with thyroid nodules before CT screening (2008-2019) (group 2). They compared the characteristics of MTC patients in groups 1 and 2.

RESULTS

MTC was identified in 30 patients (0.25%) in group 1 and 19 (0.07%) in group 2. A FNA-CT cutoff value of 4085.5 pg/mL detected MTC with a sensitivity of 96.8%, and a serum CT cutoff value of 28.3 pg/mL detected MTC with a sensitivity of 86.7%. In contrast, FNA-CY detected MTC with a sensitivity of 42.4%. In group 1, 18 patients (60%) with MTC were diagnosed with microcarcinoma, whereas only two patients (10.5%) in group 2 had microcarcinoma.

CONCLUSIONS

This study detected MTC earlier by routinely measuring serum CT in all patients with nodular thyroid disease and performing FNA-CT in those with elevated values. FNA-CT and serum CT sensitivities were significantly higher than those of FNA-CY. This study revealed different FNA-CT cutoff values compared to other studies, emphasizing the need for determining clinic-specific cutoff values.

Calcitonin levels in autoimmune atrophic gastritis-related hypergastrinemia

PURPOSE

Calcitonin (Ct) is currently the most sensitive biochemical marker of C-cell disease (medullary thyroid cancer [MTC] and C-cell hyperplasia), but its specificity is relatively low. Our aim was to examine whether autoimmune atrophic gastritis (AAG) and chronic hypergastrinemia, with or without chronic autoimmune thyroiditis (AT), are conditions associated with increased Ct levels.

METHODS

Three groups of patients were consecutively enrolled in this  multicentric study: group A consisted of patients with histologically-proven AAG (n = 13; 2 males, 11 females); group B fulfilled the criteria for group A but also had AT (n = 92; 15 males, 77 females); and group C included patients with AT and without AAG (n = 37; 6 males, 31 females).

RESULTS

Median Ct levels did not differ between the three groups. Ct levels were undetectable in: 8/13 cases (61.5%) in group A, 70/92 (76.1%) in group B, and 27/37 (73.0%) in group C. They were detectable but ≤ 10 ng/L in 4/13 (30.8%), 20/92 (21.7%) and 7/37 (18.9%) cases, respectively; and they were > 10 ng/L in 1/13 (7.7%), 2/92 (2.2%) and 3/37 (8.1%) cases, respectively (P = 0.5). Only three patients had high Ct levels (> 10 ng/L) and high gastrin levels and had an MTC. There was no correlation between Ct and gastrin levels (P = 0.353, r = 0.0785).

CONCLUSIONS

High gastrin levels in patients with AAG do not explain any hypercalcitoninemia, regardless of whether patients have AT or not. This makes it mandatory to complete the diagnostic process to rule out MTC in patients with high Ct levels and AAG.

Determinants of circulating calcitonin value: analysis of thyroid features, demographic data, anthropometric characteristics, comorbidities, medications, and smoking habits in a population with histological full exclusion of medullary thyroid carcinoma

Objective

Calcitonin (Ctn) measurement is crucial for the early diagnosis of medullary thyroid carcinoma (MTC). However, Ctn levels can be skewed/elevated due to other reasons, and the Ctn upper reference value remains controversial. In this field, studies have heterogeneous settings, published data are controversial, and no evidence has been achieved. The study's aim was to evaluate all previously investigated Ctn determinants in a population with histological exclusion of MTC.

Methods

The institutional records from 2010 to 2022 were reviewed to select patients with thyroid nodules who had undergone total thyroidectomy with histological exclusion of MTC and who had tested for Ctn just before surgery. Thyroid features, demographic and anthropometric data, comorbidities, medications, and lifestyle information were collected. Univariate and multivariate analyses were performed.

Results

A total of 127 cases were included. The median age for thyroidectomy was 51 years. Median Ctn was 1.04 pg/mL (interquartile range (IQR) 1.04-2.77), with two cases having values above 10 pg/mL. In univariate analysis, Ctn was correlated with gender (p < 0.001), body weight (p = 0.016), height (p = 0.031), body surface area (p = 0.016), thyroid size (p = 0.03), thyroglobulin (p < 0.001), and chronic kidney disease (p < 0.001). After multivariate analysis, the model with the highest accuracy included gender, chronic kidney disease, and thyroid-stimulating hormone (TSH) with an adjusted R-squared of 0.4.

Conclusions

This study demonstrates, in a population histologically proven as MTC-free, that the Ctn value is mainly influenced by gender, anthropometric/thyroid features, and chronic kidney disease, with the further impact of TSH.

Appropriate and mindful measurement of serum calcitonin in patients with thyroid nodules. A white paper

Medullary thyroid carcinoma (MTC) is an infrequent thyroid malignancy that is often diagnosed at advanced stage with consequent poor prognosis. Thus, the earlier the diagnosis of MTC, the better the prognosis. Unfortunately, the preoperative detection of MTC remains challenging in clinical practice. In fact, while ultrasound and fine-needle aspiration cytology have suboptimal performance in this context, measuring serum calcitonin (Ctn), fully recognized as the most reliable test to detect MTC, is not universally accepted as routine test in all patients with thyroid nodule(s). The authors of this paper reappraise critically the matter of Ctn measurement in view of the recent advancements in the literature to point out the essential information to be known, and then to prepare an easy-to-use guide for clinicians to appropriately consider the measurement of serum Ctn during clinical practice.

C-Cell Hyperplasia and Cystic Papillary Thyroid Carcinoma in a Patient with Type 1B Pseudohypoparathyroidism and Hypercalcitoninaemia: Case Report and Review of the Literature

Hypercalcitoninaemia has been described in patients with pseudohypoparathyroidism (PHP) type 1A and 1B. Elevated calcitonin levels are thought to result from impaired Gsα receptor signaling, leading to multiple hormone resistance. Evidence on the risk of medullary thyroid carcinoma (MTC) or C-cell hyperplasia in PHP patients with hypercalcitoninaemia is lacking. A 43-year-old Caucasian man was referred to our endocrinology clinic for chronic hypocalcemia associated with elevated serum parathormone levels and a single cystic thyroid nodule. The patient did not show skeletal deformities, and screening for concomitant hormone resistances was negative, except for the presence of elevated serum calcitonin levels. The workup led to a molecular diagnosis of sporadic PHP1B. Fine needle aspiration of the thyroid nodule was not diagnostic. The calcium stimulation test yielded an abnormal calcitonin response. Given the scarcity of data on the risk of thyroid malignancy in PHP and calcium stimulation test results, total thyroidectomy was performed. Histological examination revealed cystic papillary thyroid cancer in a background of diffuse C-cell hyperplasia. To our knowledge, we are the first to describe a rare form of thyroid cancer combined with C-cell hyperplasia in a patient with PHP and hypercalcitoninaemia. In the present case, a mere receptor resistance might not fully explain the elevated calcitonin levels, suggesting that hypercalcitoninaemia should be carefully evaluated in PHP patients, especially in the case of concomitant thyroid nodules. Further studies on larger cohorts are needed to elucidate this topic.

A bibliometric analysis based on Web of Science from 2012 to 2021: Current situation, hot spots, and global trends of medullary thyroid carcinoma

Background

Medullary thyroid carcinoma (MTC) is a special type of thyroid carcinoma derived from the C cell of the thyroid gland. Because of the poor prognosis of MTC, a large number of studies on MTC have been conducted in the last 10 years. To better comprehend, it is necessary to clarify and define the dominant countries, organizations, core journals, important authors, and their cumulative research contributions, as well as the cooperative relationships between them.

Method

English publications with article type article or review about MTC from January 2012 to December 2021 was retrieved from Web of Science core collection, and VOSviewer, CiteSpace, and Microsoft Excel were applied for bibliometric study.

Result

A total of 1208 articles and reviews were included in this study. The 1208 papers were written by 6364 authors from 1734 organizations in 67 countries, published in 408 journals, and cited 24118 references from 3562 journals. The number of publications was essentially flat from 2012-2021, with the largest proportion of publications coming from the U.S., followed by Italy and China. Thyroid was the most productive journal, and Journal of clinical endocrinology & metabolism was the most cited journal. University of Texas MD Anderson Cancer Center was the most productive institution and Luca Giovanella, was the most productive author. Diagnostic tools, surgical treatment, non-surgical treatment, genetics and relationship with other endocrine diseases were the main research interests in this field. Prognosis has been a cutting-edge topic since 2017.

Conclusion

As a thyroid cancer with poor prognosis, MTC has received continuous attention in recent years. Current MTC studies mainly focused on disease intervention, mechanism research and prognosis. The main point of this study is to provide an overview of the development process and hot spots of MTC in the last decade. These might provide ideas for further research in the MTC field.

Suboptimal accuracy of ultrasound and ultrasound-based risk stratification systems in detecting medullary thyroid carcinoma should not be overlooked. Findings from a systematic review with meta-analysis

OBJECTIVE

Ultrasound (US) is the pivotal procedure during the diagnostic work-up of thyroid nodule and several US-based risk stratification systems (RSSs) have been recently developed. Since the performance of RSSs in detecting medullary thyroid carcinoma (MTC) has been rarely investigated, the present systematic review aimed to achieve high evidence about (1) how MTC is classified according to RSSs; (2) if RSSs correctly classify MTC at high risk/suspicion, and (3) if MTC is classified as suspicious at US when RSSs are not used.

DESIGN

The review was performed according to MOOSE. The online search was performed by specific algorithm on January 2022. A random-effects model was used for statistical analysis.

RESULTS

Twenty-five papers were initially included and their risk of bias was generally low. According to ATA system, 65% of MTCs was assessed at high suspicion and 25% at intermediate suspicion. Considering all RSSs, a 54.8% of MTCs was put in a high-risk/suspicion category. Pooling data from studies without data of RSS the prevalence of ultrasonographically suspicious MTCs was 60%.

CONCLUSIONS

As conclusion, MTC presentation according to RSSs is partially known and it is classified in a high-risk/suspicion category of RSSs in just over a half of cases. This advises for further studies, ideally supported by international societies, to better define the US presentation of MTC.

An Appraisal and Update of Fluorodeoxyglucose and Non-Fluorodeoxyglucose-PET Tracers in Thyroid and Non-Thyroid Endocrine Neoplasms

Endocrine neoplasms and malignancies are a diverse group of tumors with varied clinical, histopathologic, and functional features. These tumors vary from sporadic to hereditary, isolated entities to multiple neoplastic syndromes, functioning and non functioning tumors, unifocal locally invasive, and advanced to multifocal tumors with disseminated distant metastases. The presence of various specific biomarkers and specific receptor targets serves as valuable tools for diagnosis, prognosis, and management. PET-CT with FDG and a multitude of novel and specific radiotracers towards specific therapeutic targets mandates personalization of their use, so as to ensure maximum clinical benefit in the management of these neoplasms.

The dilemma of routine testing for calcitonin thyroid nodule's patients to detect or exclude medullary carcinoma: one single negative test should be valuable as rule-out strategy to avoid further calcitonin measurements over time

PURPOSE

While calcitonin (CT) measurement is recognized as the most accurate tool to diagnose medullary thyroid carcinoma (MTC), its routine use in patients with thyroid nodule (TN) is not universally accepted. The present study raised the question whether a TN patient with an initial normal CT can have suspicious CT levels (i.e., at least >20 pg/ml) later during his follow-up.

METHODS

The historical database of our institution was searched to select TN patients undergone multiple CT tests, having an initial normal CT, and clinically followed up for years. The event of a CT above 20 pg/ml (mild-to-moderate suspicion) and 100 pg/ml (high suspicion) was searched in the follow-up of the included patients.

RESULTS

According to the study design, the study sample encompassed 170 patients (131 female, 39 male) with initial CT value ≤10 pg/ml. On the first CT test, patients were 54.8 years and median CT was 2.1 pg/ml in both females and males. Over a period of 14.5 years and a median clinical follow-up of patients of 53.0 (23.9-102.5) months, MTC could be excluded by histology or cytology in 109 (64%) and clinically in the remaining ones. On the follow-up over time, no patients had CT >20 pg/ml and only two cases had CT just above 10 pg/ml.

CONCLUSION

According to the present results, one single CT testing with normal value could be reasonably used as a rule-out strategy in patients with TN to avoid further CT measurements.

Clinical diagnostic value of American College of Radiology thyroid imaging report and data system in different kinds of thyroid nodules

BACKGROUND

To evaluate the diagnostic value of American College of Radiology (ACR) score and ACR Thyroid Imaging Report and Data System (TI-RADS) for benign nodules, medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) through comparing with Kwak TI-RADS.

METHODS

Five hundred nine patients diagnosed with PTC, MTC or benign thyroid nodules were included and classified into the benign thyroid nodules group (n = 264), the PTC group (n = 189) and the MTC group (n = 56). The area under the curve (AUC) values were analyzed and the receiver operator characteristic (ROC) curves were drawn to compare the diagnostic efficiencies of ACR score, ACR TI-RADS and KWAK TI-RADS on benign thyroid nodules, MTC and PTC.

RESULTS

The AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS for distinguishing malignant nodules from benign nodules were 0.914 (95%CI: 0.886-0.937), 0.871 (95%CI: 0.839-0.899) and 0.885 (95%CI: 0.854-0.911), respectively. In distinguishing of patients with MTC from PTC, the AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS were 0.650 (95%CI: 0.565-0.734), 0.596 (95%CI: 0.527-0.664), and 0.613 (95%CI: 0.545-0.681), respectively. The AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS for the discrimination of patients with MTC, PTC or benign nodules from patients without MTC, PTC or benign nodules were 0.899 (95%CI: 0.882-0.915), 0.865 (95%CI: 0.846-0.885), and 0.873 (95%CI: 0.854-0.893), respectively.

CONCLUSION

The ACR score performed the best, followed ex aequo by the ACR and Kwak TI-RADS in discriminating patients with malignant nodules from benign nodules and patients with MTC from PTC.

Performing Calcitonin Immunocytochemistry on an Additional ThinPrep Slide in Fine-Needle Aspiration Diagnosis of Medullary Thyroid Carcinoma

OBJECTIVES

This study reviewed the institutional experience of performing calcitonin immunostain on an additional ThinPrep slide in fine-needle aspiration (FNA) diagnosis of medullary thyroid carcinoma (MTC).

METHODS

Thyroid FNA cases with MTC suspected or included in the differential diagnosis during cytologic evaluation and calcitonin immunostain performed were retrieved and reviewed.

RESULTS

Calcitonin immunostain was performed in 132 cases with 41 positive, 81 negative, and 10 indeterminate results. All calcitonin-positive cases had a cytologic diagnosis of MTC while all calcitonin-negative cases were cytologically classified as non-MTCs except for two cases suspicious for MTC. In 10 cases with an indeterminate calcitonin result, diagnoses of non-MTC and suspicious for MTC were rendered in 6 and 4 cases, respectively. Histopathologic follow-up was available in 85 (64%) cases. All cytologically diagnosed MTC cases were confirmed on histopathology. In 3 MTC cases with an indeterminate calcitonin result, 1 case was misclassified cytologically as follicular neoplasm. The calculated sensitivity, specificity, positive predictive value, and negative predictive value of calcitonin immunostain were all 100% for diagnosing MTC.

CONCLUSIONS

Our study demonstrates the feasibility of performing calcitonin immunostain on an additional ThinPrep slide. Calcitonin immunocytochemistry is a valuable adjunct test for FNA diagnosis and differential diagnosis of MTC.

Molecular Imaging and Theragnostics of Thyroid Cancers

Molecular imaging plays an important role in the evaluation and management of different thyroid cancer histotypes. The existing risk stratification models can be refined, by incorporation of tumor-specific molecular markers that have theranostic power, to optimize patient-specific (individualized) treatment decisions. Molecular imaging with varying radioisotopes of iodine (i.e., 131I, 123I, 124I) is an indispensable component of dynamic and theragnostic risk stratification of differentiated carcinoma (DTC) while [18F]F-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) helps in addressing disease aggressiveness, detects distant metastases, and risk-stratifies patients with radioiodine-refractory DTC, poorly differentiated and anaplastic thyroid cancers. For medullary thyroid cancer (MTC), a neuroendocrine tumor derived from thyroid C-cells, [18F]F-dihydroxyphenylalanine (6-[18F]FDOPA) PET/CT and/or [18F]FDG PET/CT can be used dependent on serum markers levels and kinetics. In addition to radioiodine therapy for DTC, some theragnostic approaches are promising for metastatic MTC as well. Moreover, new redifferentiation strategies are now available to restore uptake in radioiodine-refractory DTC while new theragnostic approaches showed promising preliminary results for advanced and aggressive forms of follicular-cell derived thyroid cancers (i.e., peptide receptor radiotherapy). In order to help clinicians put the role of molecular imaging into perspective, the appropriate role and emerging opportunities for molecular imaging and theragnostics in thyroid cancer are discussed in our present review.

Head-to-head comparison of FNA cytology vs. calcitonin measurement in FNA washout fluids (FNA-CT) to diagnose medullary thyroid carcinoma. A systematic review and meta-analysis

PURPOSE

The sensitivity of cytology after fine needle aspiration (FNA-cytology) in detecting medullary thyroid carcinoma (MTC) is low. To overcome this problem, measuring calcitonin (CT) in washout fluid of FNA (FNA-CT) has been largely diffused and showed good performance. However, no evidence-based study exists comparing systematically the sensitivity of FNA-cytology and FNA-CT. This study aimed to systematically review the literature and collect data allowing a head-to-head comparison meta-analysis between FNA-cytology and FNA-CT in detecting MTC lesions.

METHODS

The online databases of PubMed/MEDLINE and Scopus were searched until June 2021. Original articles reporting the use of both FNA-cytology and FNA-CT in the same series of histologically proven MTC lesions were included They were extracted general features of each study, number of MTC lesions (nodule and neck lymph nodes), and true positive and false negatives of both FNA-cytology and FNA-CT.

RESULTS

Six studies were included. The sensitivity of FNA-cytology varied from 20% to 86% with a pooled value of 54% (95% CI 35-73%) and significant heterogeneity. The sensitivity of FNA-CT was higher than 95% in almost all studies with a pooled value of 98% (95% CI 96-100%) without heterogeneity. The sensitivity of FNA-CT was significantly higher than that of FNA-cytology.

CONCLUSIONS

FNA-CT is significantly more sensitive than FNA-cytology in detecting MTC. Accordingly, FNA-CT represents the standard method to use in patients with suspicious MTC lesions, combined with cytology.

Is there a place for measuring serum calcitonin prior to thyroidectomy in patients with a non-diagnostic thyroid nodule biopsy?

OBJECTIVE

To verify the cytopathological Bethesda System classification of thyroid nodule fine-needle aspiration biopsy (FNAB) in MTC patients and to assess the role of preoperative serum calcitonin (CT) levels in the investigation of this neoplasm in medullary thyroid cancer (MTC) patients under observation at the Uopeccan (União Oeste Paranaense de Estudos e Combate ao Câncer).

METHODS

This is a cross-sectional review of medical records of patients monitored at the thyroid cancer outpatient clinic of Uopeccan. Clinical and demographic data, laboratory tests, ultrasound images, and cytopathological findings of MTC patients were evaluated.

RESULTS

Among the 360 patients with thyroid cancer monitored in the outpatient clinic, 5.2% (n: 19/360) had MTC. The hereditary form was more prevalent (63.2%), and there was no sex preference. The most common ultrasound findings were hypoechogenicity, solid appearance and microcalcifications. The FNAB diagnoses showed a sensitivity of 47.1%, and the most common cytopathological report was Bethesda category III. Serum CT levels showed good sensitivity (84.6%) for the diagnosis of MTC, and sensitivity levels were directly associated with the size of the nodule and distant metastases.

CONCLUSION

Bethesda category III was more prevalent in this group of MTC patients. Serum CT levels were more sensitive than cytopathology for diagnosis of this neoplasm and were able to identify all patients who could not be diagnosed by FNAB.

Constitutive Cytomorphologic Features of Medullary Thyroid Carcinoma Using Different Staining Methods

(1) Background: Accurate preoperative identification of medullary thyroid carcinoma (MTC) is challenging due to a spectrum of cytomorphologic features. However, there is a scarcity of studies describing the cytomorphologic features as seen on fine-needle aspiration (FNA) smears prepared using different staining methods. (2) Methods: We performed a retrospective study on MTC cases with available FNA slides from 13 hospitals distributed across 8 Asia-Pacific countries. The differences in the constitutive cytomorphologic features of MTC with each cytopreparatory method were recorded. A comparative analysis of cytologic characteristics was carried out with appropriate statistical tests. (3) Results: Of a total of 167 MTC samples retrospectively recruited, 148 (88.6%) were interpreted as MTC/suspicious for MTC (S-MTC). The staining methods used were Papanicolaou, hematoxylin-eosin, and Romanowsky stains. Seven out of the eleven cytologic criteria can be readily recognized by all three cytopreparatory methods: high cellularity, cellular pleomorphism, plasmacytoid cells, round cells, dyshesive cells, salt-and-pepper chromatin, and binucleation or multinucleation. An accurate diagnosis was achieved in 125 (84.5%) of the 148 samples whose FNAs exhibited five or more atypical features. Conclusions: The present work is the first study on MTC to compare the morphological differences among the cytologic staining techniques. We investigated the constitutive features and the reliability of diagnostic parameters. A feasible scoring system based upon cytomorphologic data alone is proposed to achieve a high degree of diagnostic accuracy.

Circulating pro-gastrin releasing peptide (ProGRP) in patients with medullary thyroid carcinoma

OBJECTIVES

Serum calcitonin (CT) is pivotal in medullary thyroid cancer (MTC) management. Recently, progastrin releasing peptide (ProGRP) has been proposed as a candidate complementary tumor marker of MTC. As current data are sparse our study was undertaken to evaluate the distribution of ProGRP in patients with MTC and its relationship with the tumor burden. Additionally, serial measurement of CT, carcinoembryonic antigen (CEA) and ProGRP was evaluated in three patients undergoing tyrosine kinase inhibitors (TKI).

METHODS

Seventy-eight, 125 and 62 sera from patients with MTC, non-medullary malignant and benign thyroid diseases were collected, respectively. ProGRP measurement was performed by Elecsys^® assays on Cobas e601 platform (Roche Diagnostics).

RESULTS

Significantly higher ProGRP levels were found in MTC compared to non-MTC patients. Among MTC patients ProGRP levels accurately discriminate patients with active from those with cured disease and, respectively, patients with loco-regional active disease from those with distant metastasis. Finally, ProGRP performed better than CT and CEA in monitoring the response to TKI therapy in three patients monitored serially.

CONCLUSIONS

Serum ProGRP is promising as a complementary tumor marker in MTC patients. Further studies will be required, mainly focused on monitoring ProGRP during TKI treatment for early detection of resistance and assessing its usefulness to avoid the observed false positive fluctuations that occur with CT and carcinoembryonic antigen.

Basal and stimulated calcitonin for the diagnosis of medullary thyroid cancer: updated thresholds and safety assessment

PURPOSE

Reliable cut-offs for basal (bCT) and calcium stimulated calcitonin (casCT) are needed for an early and accurate diagnosis of medullary thyroid cancer (MTC).

PATIENTS AND METHODS

Fifty-four new patients with nodular goiter were enrolled and analysed together with those previously published by our group for a total of 135 cases. bCT and casCT were measured by a highly sensitive method and the results compared with histological findings. In a subgroup of patients, cardiac rhythm was recorded before and during the calcium test.

RESULTS

In both females (F) and males (M), there was a significant correlation between tumor size and bCT levels (P < 0.001). The receiver operating characteristic plot analyses showed that, for bCT, the new cut-off points able to separate non-MTC from MTC patients were > 30 (F) and > 34 pg/mL (M), whereas the best casCT thresholds were > 79 (F) and > 466 pg/mL (M). bCT was shown to harbour a high accuracy, though some cases were diagnosed only upon stimulation test. Importantly, combining bCT, below or above the cut-offs, with casCT above the cut-offs, all the MTC cases were correctly identified. A reversible sinus bradycardia was observed in 9% of cases during the test.

CONCLUSIONS

Refined cut-offs for bCT and casCT in patients with nodular goiter are reported. Sensitive bCT was shown to have a high accuracy, but the combination with casCT data was needed to identify all MTC cases. The reliability and safety of calcium test strongly favour the routine use of CT determination in nodular thyroid disease.

Clinical relevance of 18F-FDG PET/CT in the postoperative follow-up of patients with history of medullary thyroid cancer

BACKGROUND

The aim of the study was evaluation of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography with computed tomography (PET/CT) in the detection of active disease in the patients with suspected recurrence of the medullary thyroid carcinoma (MTC).

PATIENTS AND METHODS

18F-FDG PET/CT investigation was performed in 67 patients, investigated from 2010 to 2019. _ Follow up was performed from 6 to 116 months after surgery (median 16.5 months, x± SD = 29±28.9 months). Twenty five of 67 patients underwent 99mTc-dimercaptosuccinic acid (99mTc-DMSA) scintigraphy, 11 underwent somatostatin receptor scintigraphy (SRS) with 99mTc-HYNIC TOC while 11 123I-metaiodobenzylguanidine (MIBG) scintigraphy.

RESULTS

From 67 patients, 35 (52.2%) had true positive 18F-FDG PET/CT findings (TP). Average maximal standardized uptake value (SUVmax) for all TP lesions was 5.01+3.6. In 25 (37.3%) patients findings were true negative (TN). Four (6%) patients had false positive (FP) findings while three (4.5%) were false negative (FN). Thus, sensitivity of the 18F-FDG PET/ CT was 92.11%, specificity 86.21%, positive predictive value 89.74%, negative predictive value 89.29% and accuracy 89.55%. In 27 patients (40%) 18F-FDG PET/CT finding influenced further management of the patient.

CONCLUSIONS

18F-FDG PET/CT has high accuracy in the detection of metastases/recurrences of MTC in patients after thyroidectomy as well as in evaluation and the appropriate choice of the therapy.

Clinical performance of calcitonin and procalcitonin Elecsys® immunoassays in patients with medullary thyroid carcinoma

Objectives

Medullary thyroid carcinoma (MTC) is caused by a malignant transformation in the parafollicular C-cells of the thyroid, where calcitonin (CT) is released. Nowadays, CT is the main tumor marker used in the diagnosis and follow-up of MTC patients. Nonetheless, procalcitonin (PCT) has recently been proposed as a useful complementary/alternative biomarker in MTC. Our aims were to investigate the diagnostic performance of CT and PCT and their combination in the differential diagnosis between active and inactive MTC and between MTC and non-MTC thyroid diseases, respectively.

Methods

Serum samples were collected from 16 patients with active (i.e. primary tumour before surgery or post-surgical recurrent disease) and 23 with inactive (i.e. complete remission) MTC, 125 patients with non-MTC benign thyroid disease and 62 patients with non-MTC thyroid cancers, respectively. Elecsys® CT and PCT measurements were simultaneously performed on the Cobas e601 platform (Roche Diagnostics, Rotkreutz, Switzerland).

Results

Both CT and PCT median values in active MTC (94 pmol/L and 1.17 ng/mL, respectively) were significantly higher compared with inactive MTC (0.28 and 0.06) and either benign (0.37 and 0.06) or malignant (0.28 and 0.06) non-MTC. Undetectable PCT was found in five non-MTC patients with false positive CT results.

Conclusions

Elecsys® PCT assay is a highly sensitive and specific alternative MTC marker. At the very least it appears useful in patients with positive CT results as negative PCT values securely exclude active MTC. The availability of both markers on the same automated platform facilitates reflex or reflective strategies to refine the laboratory diagnosis.

Cytologic diagnosis of medullary thyroid carcinoma in the Asia-Pacific region

BACKGROUND

The accurate preoperative identification of medullary thyroid carcinoma (MTC) is challenging due to the rarity of tumor and variable cytologic appearance. The Asian experience with diagnosing MTC by fine-needle aspiration (FNA) was scarcely reported.

METHODS

Cases of MTC with available FNA slides were enrolled from 13 hospitals representing 8 Asia-Pacific countries. Clinicopathological information, including sample preparation technique, staining method, original cytologic diagnosis and review diagnosis were collected.

RESULTS

Of a total of 145 MTC cases retrospectively recruited, 99 (68.3%) were initially interpreted as MTC/suspicious for MTC (S-MTC). The distribution of original FNA diagnostic categories was not associated with the staining method or sample preparation technique. The staining methods used were Papanicolaou, hematoxylin-eosin and Romanowsky stains. Liquid-based cytology (LBC) was used only in three countries. After reviewing all cases, the diagnostic rate of MTC/S-MTC increased to 91.7% (133/145). Cases with initially unrecognized MTC had either marked pleomorphism or cytology mimicking papillary carcinoma or follicular neoplasm. Although LBC provided certain benefits, there was no significant difference in diagnostic accuracy between conventional smear and LBC. Immunocytochemistry was available in 38 cases (26.2%), all of which were correctly recognized as MTC.

CONCLUSION

Our report summarizes how MTC is handled in contemporary Asian thyroid FNA practice. Although the detection rate of MTC by cytology alone is less satisfactory, integration with ancillary tests could achieve an excellent performance. The recognition of constitutive cytomorphologic features is needed for each cytopreparatory method, which may result in a lower threshold to initiate further workup for MTC.

Characterization of "suspicious for malignancy" for non-papillary carcinoma diagnoses on thyroid fine-needle aspiration

INTRODUCTION

To evaluate the incidence, risk of malignancy, and management of "suspicious for malignancy" (SFM) for non-papillary carcinoma diagnoses according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC).

MATERIALS AND METHODS

A retrospective search was performed for all thyroid fine-needle aspirations (FNAs) with an SFM diagnosis in the electronic Pathology database at The Johns Hopkins Hospital from 2000 to 2019. During this period, a total of 644 cases were diagnosed as SFM. Of these, 55 cases of "suspicious for non-papillary thyroid carcinoma" (SNPTC) were identified. These 55 cases were then compared with 65 random cases of "suspicious for papillary thyroid carcinomas" (SPTC) diagnoses as a control group.

RESULTS

The SNPTC subgroup consisted of 28 cases of "suspicious for medullary thyroid carcinoma" (SMTC) (50.91%), 4 cases of "suspicious for metastasis" (SMET) (7.27%), 3 cases of "suspicious for malignant lymphoma" (SML) (5.45%), 2 cases of "suspicious for poorly-differentiated thyroid carcinoma" (SPDC) (3.64%), and 18 cases of "suspicious for malignancy, not otherwise specified" (SNOS) (32.73%). When compared to SPTC, SNPTC patients' average age was older (P = 0.004). Ancillary studies assisted in diagnosing SNPTC more so than SPTC (P < 0.001). Immunohistochemical studies were performed for 11 cases, molecular studies for 6 cases, and needle rinse calcitonin level for 1 case. When correlated with surgical follow-ups, the risk of malignancy (ROM) was 91.18% for SNPTC compared to 93.75 for SPTC%.

CONCLUSIONS

SNPTC was rarely diagnosed when compared with SPTC. SMTC was the most commonly diagnosed SNPTC subgroup, followed by SNOS. The ROM of SNPTC was slightly lower than that of SPTC. Ancillary studies and previous clinical history, in addition to cytomorphology, was helpful when rendering the diagnosis of SNPTC.

Highly Efficient Gold Nano-Flower Optical Biosensor Doped in a Sol-Gel/PEG Matrix for the Determination of a Calcitonin Biomarker in Different Serum Samples

We developed a novel, simple, sensitive, accurate, and precise method for the determination of calcitonin in different serum samples with medullar thyroid carcinoma. The designed flower-like thin film gold nanoparticles doped in a sol-gel/polyethylene glycol mold are used as an optical biosensor for the efficient determination of calcitonin. The sensor was characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray microanalysis, and Fourier-transform infrared spectroscopy. The efficiency of the considered bio-sensor is done using the quencher calcitonin of the emission band at 360 nm of biomarker obtained at λ_ex = 333 nm in acetonitrile solvent. The sensing mechanism was based on fluorescence resonance energy transfer. The remarkable quenching of the fluorescence intensity at 360 nm of optical sensor by various concentrations of calcitonin was successfully used as an optical biosensor for the assessment of calcitonin for different serum samples of patients with medullar thyroid carcinoma. The calibration plot was prepared for the concentration range 0.01-1000 pg/mL of calcitonin with a correlation coefficient of 0.99 and a detection limit of 0.707 pg/mL. The suggested method augments the sensitivity of calcitonin as a useful biomarker for the early diagnosis of medullar thyroid carcinoma. This method is considered as a gateway for the construction of a new prototype for the follow-up of thyroid cancer in the spinal cord during and after treatment.

An unsuspicious thyroid nodule with fatal outcome

INTRODUCTION

Over the last few years, several scientific societies have introduced specific evaluation systems to stratify the risk of malignancy of thyroid nodules. Most of these classifications have been created on the basis of ultrasonographic features of the commonest thyroid carcinoma histotype. Herein, we report a case of anaplastic thyroid carcinoma presenting at ultrasound (US) examination as an unsuspicious thyroid nodule associated with distant metastases, which was followed by the patient's death a short time later.

CASE REPORT

A 77-year-old woman, because of worsening weight loss and vague abdominal pain, underwent a whole-body computed tomography scan, which revealed a large mass adherent to the large bowel, multiple pulmonary nodules, and a solitary thyroid nodule of the left lobe. On US, a round, well-defined, mixed solid-cystic, isoechoic lesion with a maximum diameter of 45 mm and peripheral vascularity was confirmed. No microcalcifications, extrathyroidal extension, cervical lateral lymphadenopathy, tracheal deviation, or compression were found. The nodule was classified as low or very low risk according to six US malignancy risk classification systems. Although only two of these recommended fine-needle aspiration cytology, on the basis of a dimensional criterion, the procedure was performed, the cytology report suggesting anaplastic cancer. Following total thyroidectomy, the histological examination revealed the presence of a follicular thyroid carcinoma with diffuse areas of anaplastic dedifferentiation.

CONCLUSION

This case highlights the importance of defining the US characteristics of rare variants of thyroid neoplasms, since an early diagnosis is decisive in defining the patient's prognosis.

Using deep convolutional neural networks for multi-classification of thyroid tumor by histopathology: a large-scale pilot study

Background

To explore whether deep convolutional neural networks (DCNNs) have the potential to improve diagnostic efficiency and increase the level of interobserver agreement in the classification of thyroid nodules in histopathological slides.

Methods

A total of 11,715 fragmented images from 806 patients' original histological images were divided into a training dataset and a test dataset. Inception-ResNet-v2 and VGG-19 were trained using the training dataset and tested using the test dataset to determine the diagnostic efficiencies of different histologic types of thyroid nodules, including normal tissue, adenoma, nodular goiter, papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), medullary thyroid carcinoma (MTC) and anaplastic thyroid carcinoma (ATC). Misdiagnoses were further analyzed.

Results

The total 11,715 fragmented images were divided into a training dataset and a test dataset for each pathology type at a ratio of 5:1. Using the test set, VGG-19 yielded a better average diagnostic accuracy than did Inception-ResNet-v2 (97.34% vs. 94.42%, respectively). The VGG-19 model applied to 7 pathology types showed a fragmentation accuracy of 88.33% for normal tissue, 98.57% for ATC, 98.89% for FTC, 100% for MTC, 97.77% for PTC, 100% for nodular goiter and 92.44% for adenoma. It achieved excellent diagnostic efficiencies for all the malignant types. Normal tissue and adenoma were the most challenging histological types to classify.

Conclusions

The DCNN models, especially VGG-19, achieved satisfactory accuracies on the task of differentiating thyroid tumors by histopathology. Analysis of the misdiagnosed cases revealed that normal tissue and adenoma were the most challenging histological types for the DCNN to differentiate, while all the malignant classifications achieved excellent diagnostic efficiencies. The results indicate that DCNN models may have potential for facilitating histopathologic thyroid disease diagnosis.

The application value of modified thyroid imaging report and data system in diagnosing medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is highly malignant and quite different from the most common papillary thyroid carcinoma (PTC). However, most of the ultrasonic evaluation systems mainly aim at PTC at present. This study aims to evaluate the applicability of modified TI-RADS in diagnosing MTC and compare the sonographic differences of MTC, PTC, and benign nodules. Three thousand two hundred and forty-two thyroid nodules images confirmed by pathology were categorized according to modified TI-RADS and ACR TI-RADS classification. The performances of two TI-RADS were assessed by ROC curves. The correlations between classifications with the pathology and the consistency of different doctors were evaluated. The ultrasonic differences of MTC, PTC, and benign nodules were analyzed. As a result, the number of high suspicious US features increased, the malignant risk of nodules also increased of two classifications, with significant differences between categories (P < 0.001). Spearman correlation coefficients were 0.751 (modified TI-TADS) and 0.744 (ACR TI-RADS). Areas under the ROC curve of the modified TI-RADS and ACR TI-RADS were 0.960 and 0.872 (P < 0.001). At Best cut off points, the diagnostic value of modified TI-RADS was higher than that of ACR TI-RADS with a higher specificity, PPV, accuracy, and Youden index). By using modified TI-RADS to diagnose MTC and PTC, the sensitivity, specificity, NPV, accuracy, and Youden index were higher in MTC than PTC. The Kendall's correlation coefficients were 0.962, 0.930, and 0.987. MTC had special ultrasonography characters compared with PTC and benign nodules. These results suggest that modified TI-RADS is better than ACR TI-RADS in diagnosing thyroid carcinomas. Diagnostic value to MTC of modified TI-RADS is slightly higher than that to PTC, and the categorical results of different doctors were consistent. MTC had several particular features contrast to PTC and benign nodules.

Laboratory Testing in Thyroid Conditions - Pitfalls and Clinical Utility

Thyroid disorders are common, affecting more than 10% of people in the US, and laboratory tests are integral in the management of these conditions. The repertoire of thyroid tests includes blood tests for thyroid-stimulating hormone (TSH), free thyroxine, free triiodothyronine, thyroglobulin (Tg), thyroglobulin antibodies (Tg-Ab), thyroid peroxidase antibodies (TPO-Ab), TSH receptor antibodies (TRAb), and calcitonin. TSH and free thyroid hormone tests are frequently used to assess the functional status of the thyroid. TPO-Ab and TRAb tests are used to diagnose Hashimoto's thyroiditis and Graves' disease, respectively. Tg and calcitonin are important tumor markers used in the management of differentiated thyroid carcinoma and medullary thyroid carcinoma (MTC), respectively. Procalcitonin may replace calcitonin as a biomarker for MTC. Apart from understanding normal thyroid physiology, it is important to be familiar with the possible pitfalls and caveats in the use of these tests so that they can be interpreted properly and accurately. When results are discordant, clinicians and laboratorians should be mindful of possible assay interferences and/or the effects of concurrent medications. In addition, thyroid function may appear abnormal in the absence of actual thyroid dysfunction during pregnancy and in critical illness. Hence, it is important to consider the clinical context when interpreting results. This review aims to describe the above-mentioned blood tests used in the diagnosis and management of thyroid disorders, as well as the pitfalls in their interpretation. With due knowledge and care, clinicians and laboratorians will be able to fully appreciate the clinical utility of these important laboratory tests.

Medullary thyroid carcinoma: Application of Thyroid Imaging Reporting and Data System (TI-RADS) Classification

PURPOSE

To evaluate the applicability of ultrasound (US)-based Thyroid Imaging Reporting and Data System (TI-RADS) for evaluating medullary thyroid carcinoma (MTC).

MATERIALS AND METHODS

US images and medical records of patients with cytopathology-confirmed MTC between June 2003 and November 2016 were retrospectively reviewed. Four independent reviewers (two experienced and two inexperienced radiologists) evaluated 57 pre-operative US images of patients with MTC for shape, composition, echogenicity, margin, calcification of the MTC nodules, and categorized the nodules using TI-RADS classification. Weighted Kappa statistics was used to determine the inter-observer agreement of TI-RADS. Univariate and multivariate analyses were performed to assess US findings associated with lymph node metastasis.

RESULTS

Ninety-five percent of nodules were classified as either high suspicion (68%) or intermediate suspicion (26%). The overall inter-rater agreement was good (Kappa 0.84, agreement 91.52%), and inexperienced reviewers also showed good agreements with the most experienced reviewer (weighted Kappa 0.73 and 0.81). According to the univariate analysis, TI-RADS category 5, shape, microcalcification, and extrathyroid extension were significantly associated with lymph node metastasis in MTC patients (p = 0.003, 0.008, 0.001, and 0.021, respectively). As per the multivariate analysis, the presence of microcalcification and the irregular shape of the nodule were significantly associated with metastatic lymph nodes in MTC patients (odds ratio, 26.6; 95% CI, 2.7-263.7, p = 0.005, odds ratio, 14.7; 95% CI, 1.3-170, p = 0.031, respectively).

CONCLUSION

TI-RADS is applicable for the evaluation of MTC nodules with good inter-observer agreement.

Procalcitonin measurement to screen medullary thyroid carcinoma: A prospective evaluation in a series of 2705 patients with thyroid nodules

BACKGROUND

To prospectively evaluate the role of procalcitonin (PCT) in screening of patients with thyroid nodules for medullary thyroid carcinoma (MTC).

MATERIALS AND METHODS

We measured PCT in 2705 patients with thyroid nodules referred to our centre between January 2011 and December 2017. Those with a positive PCT were operated after positive confirmatory tests such as fine-needle aspiration, measurement of calcitonin (CT) in serum and fine-needle aspiration washouts or CT stimulation testing. Patients with a negative PCT were operated based on the results of further diagnostics. The diagnostic performance of PCT was evaluated, and the best cut-off level was selected by ROC curve analysis.

RESULTS

Among 2705 patients, 9 with positive serum PCT (ie, above 0.1 μg/L) and 370 with negative PCT underwent thyroid surgery. MTC was histologically confirmed in all patients with positive PCT but not found in patients with negative PCT. Serum PCT levels were significantly higher in patients with MTC (median 0.64 μg/L, range 0.16-12.9 μg/L) than in those without (median 0.075 μg/L, range 0.075-0.16 μg/L; P < .0001). ROC curves were plotted to calculate the optimal PCT value separating patients with MTC from those without. The best cut-off was 0.155 μg/L with sensitivity, specificity, positive and negative predictive values as well as accuracy of 100%, 99.7%, 91.7%, 100% and 99.7%, respectively. Positive and negative likelihood ratios were 329 and zero, respectively.

CONCLUSIONS

Measurement of PCT is a sensitive and accurate method for detecting MTC in patients with thyroid nodules and can thus be a reliable alternative to CT measurement.

Procalcitonin as Marker of Recurrent Medullary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Calcitonin measurement is pivotal in the management of medullary thyroid carcinoma (MTC), but several pitfalls can affect its reliability. Other potential markers have been proposed, and procalcitonin (ProCT) has been reported as promising. The present study was undertaken to summarize the published data and provide more robust estimates on the reliability of ProCT as marker in the management of patients with MTC.

METHODS

The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The sources comprised studies published through May 2018. Journal Articles that reported series of MTC patients undergone ProCT during postoperative follow-up were searched. A random-effects model was used for statistical pooling of the data. The I² index was used to quantify the consistency among the studies. The Egger test evaluated the possible presence of significant publication bias. Quality assessment of the studies was performed according to Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).

RESULTS

According to inclusion and exclusion criteria five papers, reporting 296 MTC patients undergone ProCT evaluation, were finally selected. The number of MTC with recurrence was 140. The pooled sensitivity of ProCT in detecting recurrence was 96% (95% confidence interval [CI], 92% to 99%), with neither heterogeneity (I²=0%) nor publication bias (Egger test, 3.16; P=0.99). The pooled specificity was 96% (95% CI, 87% to 100%) with mild heterogeneity (I²=66.6%), while Egger test was not calculable.

CONCLUSION

The present meta-analysis provides evidence that ProCT is reliable to manage MTC patients during their postoperative follow-up.

Procalcitonin as a postoperative marker in the follow-up of patients affected by medullary thyroid carcinoma

AIM

Due to the limits of calcitonin, other markers are warranted to better manage medullary thyroid carcinoma patients, and procalcitonin has been reported as promising. Here we aimed to evaluate procalcitonin as a marker of medullary thyroid carcinoma in the post-treatment follow-up.

METHODS

Medullary thyroid carcinoma patients previously treated by thyroidectomy were enrolled. After complete imaging work-up (i.e. ultrasonography, computed tomography, magnetic resonance and ¹⁸FDG-PET-CT) we identified patients with structural recurrent/persistent medullary thyroid carcinoma (active medullary thyroid carcinoma) and subjects with no evidence of disease. Then, both calcitonin and procalcitonin were measured and their performance analyzed.

RESULTS

The final series included 55 medullary thyroid carcinoma patients treated and followed-up for about five years. Of these, 43 were assessed as no evidence of disease, and 12 as active medullary thyroid carcinoma. The median value of procalcitonin was significantly higher ( P < 0.0001) in active medullary thyroid carcinoma patients (3.10 ng/mL) than in those with no evidence of disease (0.10 ng/mL). Also, calcitonin levels of active medullary thyroid carcinoma (96.7 pg/mL) were significantly ( P < 0.0001) higher than that of no evidence of disease (2.0 pg/mL). At the receiver operating characteristic curve analysis, the optimal cut-off of procalcitonin was ≥0.32 ng/mL with 92% sensitivity and 98% specificity, while the most accurate threshold of calcitonin was ≥12.0 pg/mL with 100% sensitivity and 91% specificity. There was no active medullary thyroid carcinoma with simultaneously negative results of procalcitonin and calcitonin.

CONCLUSIONS

Procalcitonin is reliable in discriminating medullary thyroid carcinoma patients with active disease from those with no evidence of disease. We suggest using procalcitonin as complementary to calcitonin to follow-up medullary thyroid carcinoma patients.

Serum calcitonin negative mixed medullary-follicular carcinoma initially diagnosed as medullary thyroid carcinoma by fine-needle aspiration cytology: A case report and review of the literatures

Medullary thyroid carcinoma (MTC) is potentially lethal. A prompt and accurate diagnosis is the prerequisite for the treatment of MTC. Fine-needle aspiration (FNA) is a reliable diagnostic tool in the assessment of thyroid nodules. However, cytologic assessment of MTC based on FNA has several drawbacks due to morphological variants. We present a case of MTC diagnosed through FNA cytology, which was eventually histologically confirmed as a mixed medullary-follicular carcinoma with negative serum calcitonin expression. Hence, diagnosis of MTC based on FNA should be applied with caution. Ultrasound characteristics of suspicious thyroid nodules are recommended to be evaluated by FNA. However, calcitonin levels should be measured in both the FNA washout fluid and serum when features of MTC are presented or cytology result is inconclusive. If adequate FNA sample is available, a supplementary immunocytochemical staining of markers such as calcitonin, chromogranin, carcinoembryonic antigen, and thyroglobulin is helpful for a correct diagnosis of MTC.

Patients with papillary thyroid carcinoma associated with high stimulated serum calcitonin levels

Among various substances produced by C-cells, the most important one is calcitonin (CT) that is used for detection, post-operative follow-up and evaluation of individuals at risk of developing medullary thyroid carcinoma (MTC). However, the role of serum CT measurement in the evaluation of thyroid nodules has been widely discussed, and there is still no consensus about the role of CT in the initial evaluation of all thyroid nodules. Two patients with thyroid nodules whose fine-needle aspiration results were compatible with benign cytology besides having mildly elevated basal serum calcitonin levels were reported. Calcitonin responses (peak levels were 313 and 229 pg/mL, respectively) to calcium stimulation test were compatible with the possible diagnosis of MTC. However, the final diagnosis was papillary thyroid carcinoma of the thyroid gland. There are limited numbers of case reports showing such an increased serum calcitonin responses to calcium stimulation test associated with papillary or follicular thyroid carcinoma of the thyroid. We suggest to measure serum CT level once and in case of normal levels, no further CT measurement is necessary. Physicians should keep in mind that thyroid carcinomas other than MTCs may also be associated with high serum CT levels.

Learning points

Although serum calcitonin is a valuable tumor marker for MTC, it is well known that mild elevations may be seen in some other diseases such as Hashimoto thyroiditis, neuroendocrine tumors or due to medications such as proton pump inhibitors, calcium salts, beta blockers and glucocorticoids.Those two cases indicate that high calcitonin responses to calcium stimulation test, mimicking MTC, may also be seen in patients with papillary thyroid carcinoma although the mechanism is not clear.

A large Chinese pedigree of multiple endocrine neoplasia type 2A with a novel C634Y/D707E germline mutation in RET exon 11

The present study identified the clinical features of the largest multiple endocrine neoplasia type 2 (MEN2) A pedigree from China, with a novel double missense rearranged during transfection (RET) mutation (C634Y/D707E). To the best of our knowledge, the D707E mutation has not been identified to date. In the present study, a total of 101 family members who originated from a large pedigree (134 members in total) underwent RET mutation screening by next-generation sequencing and polymerase chain reaction (PCR) amplification, followed by direct bidirectional DNA sequencing. The clinical features of this pedigree were carefully reviewed retrospectively, and statistical analyses were conducted using SPSS software. A total of 33 (32.67%) carriers were identified to exhibit the C634Y/D707E RET germline mutation. The mean age of the patients with medullary thyroid carcinoma (MTC) identified by RET screening was 38.4±16.5 years (n=11; range, 14–65 years). Only 4 patients with pheochromocytoma with a median age of 37 years were identified. No hyperparathyroidism was diagnosed. Persistent or recurrent disease developed in the patients of the present study who underwent inappropriate initial thyroid surgeries that were performed in previous decades (III10, III23, III24, III27 and IV46, as they had undergone two surgeries prior to the present study). A total of 66.70% (6/9) of patients, following thyroidectomy, continued to develop persistent or recurrent disease during the present screening study. In total, 3 patients succumbed to MTC or distant metastasis in the present study. The increase in carcinoembryonic antigen (CEA) levels correlated with the increase in basal serum calcitonin (Ct) levels according to Pearson correlation analysis in patients with MTC without surgery. Ct and CEA levels were also significantly correlated with tumor volumes. To the best of our knowledge, the present study is the first to identify a novel double RET missense mutation in the largest MEN2A pedigree from China. Additional in-depth study is necessary to elucidate the molecular mechanisms of the D707E mutation and its potential joint effects with the other C634Y mutation in the pedigree of the present study.

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.

Oncocytic variant of medullary thyroid carcinoma; a rare tumor with numerous diagnostic mimics by fine needle aspiration

Oncocytic variant of medullary thyroid carcinoma is rare form of thyroid carcinoma that is easily misdiagnosed on fine needle aspiration specimens due to it is low incidence and cytomorphologic overlap with other more common Hurtle cell lesions. A correct initial diagnosis by fine needle aspiration is imperative as the clinical treatment for medullary carcinoma differs significantly from the mimickers. We present a case of this rare variant tumor that on initial fine needle aspiration was described as a Hurthle cell lesion and was subsequently correctly classified on the resection specimen. In this brief review, we describe the cytomorphologic features of medullary carcinoma, oncocytic variant of medullary carcinoma and it is most common mimickers, and we discuss the ancillary studies required to confirm the diagnosis. This case highlights the importance of a complete clinical history and radiologic correlation, which in conjunction with a careful attention to the cytologic features of the fine needle aspiration sample, should in most cases ensure a correct initial diagnosis.

Measurement of thyroglobulin, calcitonin, and PTH in FNA washout fluids

Different imaging tools, circulating endocrine markers, and fine-needle aspiration (FNA) cytology are of great importance in the diagnosis and follow-up of different thyroid and parathyroid diseases. Sometimes, however, they are conflicting or inconclusive: interestingly, measuring endocrine markers (i.e. thyroglobulin, calcitonin, parathyroid hormone) in fluids from FNA proved to be a very useful complementary diagnostic tool in such cases. The determination of endocrine markers in fluids other than serum/plasma has been developed in the last years. Although studies have reported overall satisfactory results, a good standardization of procedures has not yet been reached, and further efforts should be made in order to better define pre-analytical, analytical, and post-analytical aspects. Here we reviewed critically the literature on the measurement of FNA endocrine markers, focusing on laboratory issues, such as preparation of the sample, choice of solution, and technical features of determination of these markers. Indeed, information for use of FNA-Tg, FNA-CT, and FNA-PTH in clinical practice was also provided.

Detection of Biosynthetic Precursors, Discovery of Glycosylated Forms, and Homeostasis of Calcitonin in Human Cancer Cells

The peptide hormone calcitonin is intimately connected with human cancer development and proliferation. Its biosynthesis is reasoned to proceed via glycine-, α-hydroxyglycine-, glycyllysine-, and glycyllysyllysine-extended precursors; however, as a result of the limitations of current analytical methods, until now, there has been no procedure capable of detecting these individual species in cell or tissue samples. Therefore, their presence and dynamics in cancer had not been established. Here, we report the first methodology for the separation, detection, and quantification of calcitonin and each of its precursors in human cancer cells. We also report the discovery and characterization of O-glycosylated calcitonin and its analogous biosynthetic precursors. Through direct and simultaneous analysis of the glycosylated and nonglycosylated species, we interrogate the hormone biosynthesis. This shows that the cellular calcitonin level is maintained to mitigate effects of biosynthetic enzyme inhibitors that substantially change the proportions of calcitonin-related species released into the culture medium.

Utility of proGRP as a tumor marker in the medullary thyroid carcinoma

Background:

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor caused by a malignant transformation in the parafollicular C-cells of the thyroid, where calcitonin (CT) is released. Nowadays the main tumor markers (TM) used in the diagnosis and follow-up of MTC patients are CT and carcinoembryonic antigen (CEA). Nonetheless, progastrin releasing peptide (proGRP) has been recently proposed as a TM useful in the MTC. Our aims were to investigate the release of proGRP in thyroid tumors, its role in the assessment of advanced MTC and its utility in the differential diagnosis between MTC and non-MTC thyroid tumors.

Methods:

Serum samples from 22 patients with MTC and 16 with non-MTC were collected. Patients were classified into advanced cancer or no evidence of disease (NED). ProGRP was performed by Architect (Abbot Diagnostics), CT by Liaison (Diasorin) and CEA by Cobas E601(Roche Diagnostics).

Results:

ProGRP median concentration in advanced MTC was significantly higher (1398.4 pg/mL) when compared with non-MTC, either in advanced disease (24.9 pg/mL) or NED (14.6 pg/mL). In non-MTC patients, proGRP median concentration was below its cutoff level (50 pg/mL). Similar to CT, proGRP was able to detect 88.9% of MTC patients, but with a slightly lower specificity of 76.9%. Using proGRP together with CT the sensitivity increased to 100%.

Conclusions:

The low prevalence of this malignancy strongly recommends further collaborative studies, mainly focused on monitoring proGRP during tyrosine kinase inhibitors treatment for early detection of resistance and assessing its usefulness to avoid the observed false positive fluctuations that occur with CT and CEA.

Hypervascularity is more frequent in medullary thyroid carcinoma: Compared with papillary thyroid carcinoma

This study was designed to retrospectively compare the sonographic features of medullary thyroid carcinoma (MTC) and the features of papillary thyroid carcinoma (PTC).A total of 97 patients with 127 MTCs between January 2000 and January 2016 and 107 consecutive patients with 132 PTCs were included in this study. Two radiologists retrospectively determined the sonographic features and compared the findings of MTCs and PTCs.Compared with the patients with PTCs, the patients with MTCs were older (46.9 years vs 42.9 years, P = 0.016) and the male proportion was higher (53.6% vs 33.6%, P = 0.005). Most of the MTCs had an irregular shape (72.4%), a length/width ratio <1 (75.6%), an unclear boundary (63.8%), no peripheral halo ring (93.7%), hypoechogenicity (96.9%), heterogeneous echotexture (76.4%), no cystic change (78.7%), calcification (63.8%), and hypervascularity (72.4%). There was no significant difference in the boundary, peripheral halo ring, echogenicity, and calcification between the MTCs and PTCs. However, compared with the PTCs, a larger size (2.2 vs 1.2 cm, P <0.001), a regular shape (27.6% vs 7.6%, P <0.001), a length/width ratio <1 (75.6% vs 51.5%, P<0.001), heterogeneous echotexture (76.4% vs 54.5%, P <0.001), cystic change (21.3 vs 8.3%, P = 0.005), and hypervascularity (72.4% vs 47.7%, P <0.001) were more frequent in the MTCs.The sonographic features with a higher likelihood of malignancy are common in MTCs, including a shape taller than the width, irregular infiltrative margins, an absent halo, hypoechogenicity, the presence of microcalcifications, and increased intranodular vascularity. However, MTCs tend to possess these suspicious sonographic features less often than PTCs, with the exception of hypervascularity, which was more frequent in MTCs.

Clinical challenges with calcitonin-negative medullary thyroid carcinoma

PURPOSE

Medullary thyroid carcinoma (MTC) is a relatively uncommon malignant tumor of the parafollicular C cells of the thyroid, which distinguishing feature is the production of calcitonin (CT). CT is a well-recognized tool in the diagnosis and the postsurgical follow-up of patients with MTC with a high sensitivity and specificity, and represents a powerful prognostic indicator. Usually, there is a direct correlation between tumor size and basal CT levels. However, few cases of CT-negative MTCs have been reported in literature and criteria for diagnosis and follow-up are still controversial.

METHODS

We performed a brief review on CT-negative MTC and reported our experience on this rare condition, focusing on the clinical characteristics at presentation, the histological and immunostaining features, and the management.

RESULTS

Fifteen cases of large, palpable, CT-negative MTCs have been reported in the literature so far; moreover, we reported four cases followed at our center.

CONCLUSIONS

Although CT-negative MTC is rare, normal/low serum levels of CT and CEA cannot completely exclude the possibility of the diagnosis, when suspected. It is well accepted that early diagnosis is crucial, but there is still no consensus on the optimal postoperative surveillance strategy. The ultrasound evaluation of the cervical region, together with abdominal computerized tomography scan, chest X-ray, and fluorine18-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (FDG-PET/CT), would be recommended in the follow-up of such cases.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS, AMERICAN COLLEGE OF ENDOCRINOLOGY, AND ASSOCIAZIONE MEDICI ENDOCRINOLOGI MEDICAL GUIDELINES FOR CLINICAL PRACTICE FOR THE DIAGNOSIS AND MANAGEMENT OF THYROID NODULES--2016 UPDATE

Thyroid nodules are detected in up to 50 to 60% of healthy subjects. Most nodules do not cause clinically significant symptoms, and as a result, the main challenge in their management is to rule out malignancy, with ultrasonography (US) and fine-needle aspiration (FNA) biopsy serving as diagnostic cornerstones. The key issues discussed in these guidelines are as follows: (1) US-based categorization of the malignancy risk and indications for US-guided FNA (henceforth, FNA), (2) cytologic classification of FNA samples, (3) the roles of immunocytochemistry and molecular testing applied to thyroid FNA, (4) therapeutic options, and (5) follow-up strategy. Thyroid nodule management during pregnancy and in children are also addressed. On the basis of US features, thyroid nodules may be categorized into 3 groups: low-, intermediate-and high-malignancy risk. FNA should be considered for nodules ≤10 mm diameter only when suspicious US signs are present, while nodules ≤5 mm should be monitored rather than biopsied. A classification scheme of 5 categories (nondiagnostic, benign, indeterminate, suspicious for malignancy, or malignant) is recommended for the cytologic report. Indeterminate lesions are further subdivided into 2 subclasses to more accurately stratify the risk of malignancy. At present, no single cytochemical or genetic marker can definitely rule out malignancy in indeterminate nodules. Nevertheless, these tools should be considered together with clinical data, US signs, elastographic pattern, or results of other imaging techniques to improve the management of these lesions. Most thyroid nodules do not require any treatment, and levothyroxine (LT4) suppressive therapy is not recommended. Percutaneous ethanol injection (PEI) should be the first-line treatment option for relapsing, benign cystic lesions, while US-guided thermal ablation treatments may be considered for solid or mixed symptomatic benign thyroid nodules. Surgery remains the treatment of choice for malignant or suspicious nodules. The present document updates previous guidelines released in 2006 and 2010 by the American Association of Clinical Endocrinologists (AACE), American College of Endocrinology (ACE) and Associazione Medici Endocrinologi (AME).