Current update on medullary thyroid carcinoma

Atypical Presentation of Liver Metastasis in Medullary Thyroid Carcinoma: Variable Pattern and Interlesional Heterogeneity Observed on 18F-FDG, 68Ga-DOTATATE, and 68Ga-DOTA-FAPI-04 PET/CT

Metastatic medullary thyroid carcinoma (MTC) can exhibit variable progression, with liver metastases occurring in up to 62% of cases. We report an unusual case of 50-year-old man with progressive MTC and atypical hypodense metastasis in the left lobe of liver that showed no tracer avidity on conventional 18F-FDG and 68Ga-DOTATATE PET/CT but was intensely avid on 68Ga-DOTA-FAPI-04 PET/CT, implying a possible role of FAPI PET/CT imaging in diagnosing unusual metastatic lesions that may be missed on conventional PET imaging and also its theranostic potential for future management.

Comparison of Two Chelator Scaffolds as Basis for Cholecystokinin-2 Receptor Targeting Bimodal Imaging Probes

Background/Objectives: Dual-modality probes, combining positron emission tomography (PET) with fluorescence imaging (FI) capabilities in a single molecule, are of high relevance for the accurate staging and guided resection of tumours. We herein present a pair of candidates targeting the cholecystokinin-2 receptor (CCK2R), namely [68Ga]Ga-CyTMG and [68Ga]Ga-CyFMG. In these probes, the SulfoCy5.5 fluorophore and two units of a CCK2R-binding motif are coupled to the chelator acting as a core scaffold, triazacyclononane-phosphinic acid (TRAP), and Fusarinine C (FSC), respectively. Using this approach, we investigated the influence of these chelators on the final properties. Methods: The synthetic strategy to both precursors was based on the stoichiometric conjugation of the components via click chemistry. The characterization in vitro included the evaluation of the CCK2R affinity and internalization in A431-CCK2R cells. Ex vivo biodistribution as well as PET and FI studies were performed in xenografted mice. Results: 68Ga labelling was accomplished with high radiochemical yield and purity for both precursors. A CCK2R affinity in the subnanomolar range of the conjugates and a receptor-specific uptake of the radioligands in cells were observed. In A431-CCK2R/A431-mock xenografted mice, the investigated compounds showed specific accumulation in the tumours and reduced off-target uptake compared to a previously developed compound. Higher accumulation and prolonged retention in the kidneys were observed for [68Ga]Ga-CyTMG when compared to [68Ga]Ga-CyFMG. Conclusions: Despite the promising targeting properties observed, further probe optimization is required to achieve enhanced imaging contrast at early timepoints. Additionally, the results indicate a distinct influence of the chelators in terms of renal accumulation and retention.

Correlation of 18F-sodium fluoride uptake and radiodensity in extraosseous metastases of medullary thyroid carcinoma

Objective

Although 18F-sodium fluoride (18F-NaF) uptake is frequently observed in extraosseous metastases of medullary thyroid carcinoma (MTC) with calcification, itcan also occur in metastatic sites without visible calcium deposition, leading to the hypothesis that visually undetectable calcium accumulation may be responsible for this uptake. The aim of this study was to indirectly support this hypothesis by analyzing the correlation between the degree of 18F-NaF uptake and radiodensity in extraosseous MTC metastases, since calcium deposition can increase attenuation even when not visually detectable.

Subjects and methods

Extraosseous metastatic lesions of 15 patients with MTC were evaluated using 18F-NaF positron-emission tomography (PET)/computed tomography (CT)and segmented by levels of standardized uptake value (SUV). The correlation between mean SUV and mean Hounsfield unit (HU) values was assessed for the entire group of segments and for two subgroups with different mean HU values.

Results

Very high correlations were observed between mean SUV and mean HU values for both the entire group of segments and the subgroup with a mean HU value greater than 130 (p = 0.92 and p = 0.95, respectively; p < 0.01). High correlation (p = 0.71) was also observed in the subgroup with mean HU values ranging from 20 to 130 (p < 0.01).

Conclusion

The findings of the present study suggest that there is an association between 18F-NaF uptake and calcium deposition in extraosseous metastasesof MTC, supporting the hypothesis that visually undetectable calcium accumulation may be responsible for 18F-NaF uptake in regions without visible calcium deposition.

Survival Outcomes of Medullary Thyroid Cancer With and Without Amyloid Deposition

OBJECTIVE

Amyloid deposition within tumor stroma is a distinctive histologic feature of medullary thyroid cancer (MTC). However, its prognostic significance remains uncertain. We aimed to elucidate the impact of amyloid status on survival outcomes in a large cohort.

METHODS

The Surveillance, Epidemiology, and End Results registry was queried to identify patients diagnosed with MTC from 2000 to 2019. Patients with amyloid-positive (International Classification of Diseases for Oncology, third edition code 8345/3) and amyloid negative (International Classification of Diseases for Oncology, third edition code 8510/3) tumors were analyzed. Overall and disease-specific survival were compared between matched cohorts using Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

Of the 2526 MTC patients, 511 of which were amyloid-positive and 2015 that were amyloid negative. Amyloid-positive patients displayed lower T stage (T3/4: 28% vs 85%, P < .001) and less extrathyroidal extension (11.3% vs 81.6%, P < .001). No difference in distant metastasis rate was observed between groups (14.5% vs 14.4%, P = .98). However, amyloid-positive patients showed a tendency for distal lymph node metastasis (1.2% vs 0.3%, P = .020). On univariate analysis, amyloid-positive status showed comparable overall survival times (mean 172.2 vs 177.8 months, P = .17), but a trend toward worse cancer-specific survival (hazard ratios [HR] = 1.31, 95% CI = 0.99-1.71, P = .051). After adjusting for covariates, amyloid deposition did not independently predict overall (HR = 1.15, 95% CI = 0.91-1.47, P = .25) or cancer-specific survival (HR = 1.30, 95% CI = 0.96-1.77, P = .09). Initiating therapy later than 1 month following diagnosis was associated with worse overall survival (HR = 1.25, 95% CI = 1.02-1.54, P = .029).

CONCLUSIONS

The presence of amyloid in MTC paradoxically associates with lower T stage yet exhibits a trend toward worse cancer-specific mortality. Amyloid deposition alone does not independently influence prognosis. Delayed treatment adversely impacted overall survival.

Risk factors for cervical lymph node metastasis in the central or lateral cervical region in medullary thyroid carcinoma: a systematic review and meta-analysis

PURPOSE

Compared with other types of thyroid carcinoma, patients with medullary thyroid carcinoma (MTC) are more likely to develop cervical lymph node metastasis. This study was conducted to clarify the risk factors for cervical lymph node metastasis (central lymph node metastasis or lateral cervical lymph node metastasis) in MTC by meta-analysis, and to provide evidence-based basis for the treatment and prognosis of MTC.

METHODS

The literatures related to cervical lymph node metastasis in medullary thyroid carcinoma were searched in PubMed, Embase, Web of Science, Cochrane, CNKI and Wanfang databases, and statistical analysis was performed using Revman 5.3 and Stata 14.0 software.

RESULTS

A total of 28 papers were included in this paper, and meta-analysis showed that the occurrence of central lymph node metastasis (CLNM) in MTC patients was significantly associated with tumor size (OR = 3.07, 95%CI: 2.04-4.63, P < 0.00001), multifocality (OR = 0.29, 95%CI: 0.19-0.44, P < 0.00001), bilaterality (OR = 3.75, 95% CI: 1.95-7.14, P < 0.0001), capsular invasion (OR = 9.88, 95% CI: 5.93-16.45, P < 0.00001) and extrathyroidal extension (OR = 5.48, 95% CI: 2.61-11.51, P < 0.00001). While the occurrence of lateral cervical lymph node metastasis (LLNM) in MTC patients was strongly correlated with gender (OR = 2.97, 95%CI: 2.46-3.58, P < 0.00001), tumor size (OR = 3.88, 95%CI: 1.90-7.92, P = 0.0002 < 0.05), multifocality (OR = 0.43, 95%CI: 0.35-0.51, P < 0.00001), bilaterality (OR = 2.93, 95% CI: 1.72-4.98, P < 0.0001), capsular invasion (OR = 8.44, 95% CI: 6.11-11.64, P < 0.00001), extrathyroidal extension (OR = 7.04, 95% CI: 5.54-8.94, P < 0.00001), margin of the tumor (OR = 4.47, 95% CI: 2.37-8.44, P < 0.00001), shape of the tumor (OR = 6.81, 95% CI: 3.64-12.73, P < 0.00001), preoperative calcitonin level (SMD = 1.39, 95% CI: 0.98-1.80, P < 0.00001), preoperative carcinoembryonic antigen level (SMD = 0.97, 95% CI: 0.74-1.20, P < 0.00001) and CLNM (OR = 19.70, 95% CI: 14.16-27.43, P < 0.00001).

CONCLUSION

Tumor size, multifocality, bilaterality, capsular invasion and extrathyroidal extension are the main risk factors for developing CLNM in MTC patients; And risk factors for developing LLNM in MTC patients include: gender, tumor size, multifocality, bilaterality, capsular invasion, extrathyroidal extension, margin of the tumor, shape of the tumor, preoperative calcitonin level, preoperative carcinoembryonic antigen level and central lymph node metastasis. These risk factors can guide the individualized treatment plan and improve the prognosis of MTC patients.

Management of Advanced Medullary Thyroid Carcinoma: Current Systemic Therapy Options

The current rapid development of more selective and effective drugs for the treatment of thyroid cancer has open a new era in the treatment of patients with this condition, in the past limited to the possibility of only radioactive iodine for well differentiated tumor and surgery for medullary thyroid carcinoma (MTC). The treatment of advanced medullary thyroid carcinoma has evolved in the last few years and options for patients with advanced disease are now available. Multikinase inhibitors (MKIs) with nonselective RET inhibition like Vandetanib and Cabozantinib were approved for the treatment of MTC, although the efficacy is limited due to the lack of specificity resulting in a higher rate of drug-related adverse events, leading to subsequent dose reductions, or discontinuation, and the development of a resistance mechanism like seen on the RET Val804 gatekeeper mutations. MTC is associated with mutations in the RET protooncogene, and new highly selective RET inhibitors have been developed including Selpercatinib and Pralsetinib, drugs that have demonstrate excellent results in clinical trials, and efficacy even in the presence of gatekeeper mutations. However, despite their efficacy and great tolerability, mechanisms of resistance have been described, such as the RET solvent front mutations. Due to this, the need of constant evolution and drug research is necessary to overcome the emergence of resistance mechanisms.

Exploring the application value of pro-gastrin-releasing peptide in the clinical diagnosis and surgical treatment of medullary thyroid carcinoma

OBJECTIVE

To investigate the relationship between pro-gastrin-releasing peptide (ProGRP) and the clinical characteristics of patients with medullary thyroid carcinoma (MTC) and the value of ProGRP in surgical treatment monitoring.

PATIENTS AND METHODS

A total of 347 patients with MTC and non-MTC malignant and benign thyroid diseases were enrolled. The concentrations of neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), calcitonin (CT), and ProGRP were determined by Elecsys® assays. The NSE, CEA, CT, and ProGRP levels in different thyroid disease groups were compared, and ProGRP levels in different clinicopathological feature groups pre and postoperatively were further compared.

RESULTS

The CT, CEA, NSE, and ProGRP levels were upregulated in the MTC group compared to those in the non-MTC malignant and benign thyroid disease groups. The area under the receiver operating characteristic curve (AUC) of ProGRP for the diagnosis of MTC was 0.832(0.787-0.871), similar to that of CT and CEA. The sensitivity and specificity were 71.4% and 92.7%, respectively, and the optimal cut-off value was 61.8 pg/mL. The AUC of ProGRP combined with CT or CEA for the diagnosis of MTC was 0.933 (0.900-0.958) and 0.922 (0.886-0.949), respectively, which were higher than those of a single index. ProGRP levels were higher in patients with lymph nodes and distant metastases than in patients without metastases. The postoperative level of ProGRP was lower than that before treatment.

CONCLUSION

ProGRP is comparable to CEA and CT as an MTC biomarker with broad prospects. It has potential application value in the progression of MTC assessment and the evaluation of surgical intervention effects.

Prognosis of radiotherapy in medullary thyroid carcinoma patients without distant metastasis

Background

Medullary thyroid carcinoma (MTC) is an advanced disease with a poor prognosis. Although radiotherapy is widely utilized to treat MTC, it is still controversial. MTC patients without distant metastases have not been investigated to explore indications for adjuvant radiotherapy. This study aims to investigate the impact of radiotherapy on the survival of MTC patients without distant metastases.

Methods

Data of MTC patients without distant metastasis who underwent total thyroidectomy between 2010 and 2015 were obtained from the Surveillance, Epidemiology and End Results (SEER) database. Propensity score matching was performed to analyze the relationship between radiotherapy and cancer-specific survival (CSS).

Results

Seventy-four of 718 MTC patients without distant metastases received radiotherapy and underwent total thyroidectomy. A total of 148 patients were screened via propensity score matching analysis. Multivariate Cox regression indicated that factors including age, sex, radiotherapy and chemotherapy were independent predictors of CSS. Based on these factors, MTC patients without distant metastasis were classified into two risk groups using a nomogram and risk classification system. The C-index of the nomogram was 0.791. The calibration curves showed good consistency of CSS between the actual observation and the nomogram prediction, and decision curve analysis (DCA) showed great clinical usefulness of the nomogram. The three-year CSS of the radiotherapy group was 85.3%, and that of the surgery group was 95%. Particularly, compared with the surgery group, the three-year CSS of subgroups of the radiotherapy group, including male patients and those aged >48 years, was decreased.

Conclusions

Radiotherapy results in worse CSS for MTC patients without distant metastases. To maximize benefits, decisions about individual radiotherapy should weigh its advantages and disadvantages.

Imaging of Treated Thyroid and Parathyroid Disease

The thyroid and parathyroid glands are endocrine structures located in the visceral space of the infrahyoid neck. Imaging plays a critical role in the evaluation of patients with thyroid cancer, both in the pre and posttreatment setting. Disorders of thyroid function, that is, hyperthyroidism and hypothyroidism, are also fairly common, although imaging utilization is less frequent with these conditions. Parathyroid dysfunction results in disordered calcium metabolism. Imaging is frequently applied in the preoperative assessment of these patients undergoing parathyroidectomy; however, routine imaging in the postoperative setting is uncommon. Parathyroid carcinoma is rare; however, imaging may be used in the pre and posttreatment setting.

PET/Computed Tomography in Thyroid Cancer

Primary thyroid cancers demonstrate distinct biological behaviors depending on their histologic characteristics. The ability to accumulate radioiodine by differentiated thyroid cancer cells is lost in primary aggressive, poorly differentiated and dedifferentiated tumor cells. PET imaging comes into play in these challenging situations where it can provide additive information to radioiodine scintigraphy and conventional imaging. This review focuses on the current guidelines and future prospects of PET imaging in thyroid cancers.

Ultrasound of Thyroid Nodules and the Thyroid Imaging Reporting and Data System

Benign or malignant thyroid nodules are common in adults. Fine needle aspiration biopsy is the gold standard for diagnosis. Most thyroid nodules are benign. Ultrasound imaging is the optimal noninvasive imaging modality to determine which nodules demonstrate malignant features. The American College of Radiology Thyroid Imaging Reporting and Data System committee published a standardized approach to classifying nodules on ultrasound. The ultrasound features in this system are categorized as benign, minimally suspicious, moderately suspicious, or highly suspicious for malignancy. Applying the Thyroid Imaging Reporting and Data System results in a meaningful decrease in the number of thyroid nodules biopsied.

Clinical value of color Doppler ultrasound combined with serum tumor markers for the diagnosis of medullary thyroid carcinoma

The present study aimed to explore the clinical value of color Doppler ultrasound combined with serum tumor markers, including calcitonin (CT) and carcinoembryonic antigen (CEA), for the diagnosis of medullary thyroid carcinoma (MTC). A total of 39 patients with MTC (MTC group), 50 patients with papillary thyroid carcinoma (PTC) (PTC group) and 30 patients with thyroid adenoma (benign control group) were enrolled in the present study. The patients were hospitalized at the Affiliated Hospital of Qingdao University from January 2012 to December 2018 and were diagnosed through surgical procedures and pathology laboratory results. The ultrasound results, as well as serum CT and CEA results, were collected and analyzed. A significant difference was observed between the MTC and PTC groups in regards to morphology, margin, aspect ratio, calcification, internal blood flow and lymph node metastasis (all P<0.01). There was also a significant difference between the MTC and benign control group in regards to internal echo, calcification, internal blood flow and lymph node metastasis (all P<0.01). In addition, the levels of serum CT and CEA in the MTC group were significantly higher than those in the PTC and the benign control groups (both P<0.01). For patients with MTC, the levels of serum CT and CEA were significantly associated with maximum tumor diameter, lymph node metastasis and the patient state after treatment (all P<0.01). Furthermore, the sensitivities of ultrasound, serum CT and CEA for the diagnosis of MTC were 76.92, 74.36 and 68.23%, respectively. The value for the combination of the three markers (94.87%) was significantly higher compared with the sensitivity value of each separate marker (all P<0.05). In conclusion, color Doppler ultrasound combined with detecting the levels of serum tumor markers (CT and CEA) significantly improved the diagnostic efficiency for MTC, which could be useful for the clinical diagnosis and treatment of MTC.

Multimodality Imaging Review of Multiple Endocrine Neoplasia

OBJECTIVE. The purpose of this article is to review the clinical manifestations, endocrine tumors types, and multimodality diagnostic tools available to physicians involved in the management of patients with multiple endocrine neoplasia (MEN) syndrome, in addition to discussing relevant imaging findings and appropriate imaging follow-up. CONCLUSION. Thorough knowledge of the spectrum of tumors associated with MEN gene mutations aids in the screening, diagnostic workup, and posttreatment monitoring of patients with MEN-related gene mutations.

Medullary thyroid cancer: epidemiological pattern and factors contributing to recurrence and metastasis

INTRODUCTION

Medullary thyroid carcinoma (MTC) is a neuroendocrine thyroid carcinoma with parafollicular C cell differentiation. It can occur in either sporadic or hereditary form. Surgery is still the only curative treatment. The efficacy of chemotherapy and radiotherapy is poor.

METHODS

This was a retrospective study of 31 patients treated surgically for MTC in our oncology centre at Mansoura University between January 2008 and February 2019.

RESULTS

The mean age at diagnosis was 39.9 years. The median pathological size was 4cm. Multifocal disease was found in 12 patients and extrathyroid extension in 3 cases. Twenty patients were pathologically node positive. The median number of positive lymph nodes was four. Seven cases were metastatic at diagnosis. Local recurrence occurred in six individuals while distant recurrence occurred only in one. The median time from surgery to local recurrence was 12 months. The estimated mean disease free survival was 56.5 months. Disease free survival was significantly related to age, metastasis and side of nodal spread.

CONCLUSIONS

In our study cohort, the disease occurred predominantly in women and younger patients. Age, distant metastasis and nodal spread were the most significant prognostic factors. This study has also demonstrated that prognosis is not only affected by nodal involvement but also by side of involvement. The role of hemithyroidectomy in node negative unifocal disease with a small tumour size warrants further investigation.

Cholecystokinin-2 Receptor Targeting with Radiolabeled Peptides: Current Status and Future Directions

A wide variety of radiolabeled peptide analogs for specific targeting of cholecystokinin- 2 receptors (CCK2R) has been developed in the last decades. Peptide probes based on the natural ligands Minigastrin (MG) and Cholecystokinin (CCK) have a high potential for molecular imaging and targeted radiotherapy of different human tumors, such as Medullary Thyroid Carcinoma (MTC) and Small Cell Lung Cancer (SCLC). MG analogs with high persistent uptake in CCK2R expressing tumors have been preferably used for the development of radiolabeled peptide analogs. The clinical translation of CCK2R targeting has been prevented due to high kidney uptake or low metabolic stability of the different radiopeptides developed. Great efforts in radiopharmaceutical development have been undertaken to overcome these limitations. Various modifications in the linear peptide sequence of MG have been introduced mainly with the aim to reduce kidney retention. Furthermore, improved tumor uptake could be obtained by in situ stabilization of the radiopeptide against enzymatic degradation through coinjection of peptidase inhibitors. Recent developments focusing on the stabilization of the Cterminal receptor binding sequence (Trp-Met-Asp-Phe-NH2) have led to new radiolabeled MG analogs with highly improved tumor uptake and tumor-to-kidney ratio. In this review, all the different aspects in the radiopharmaceutical development of CCK2R targeting peptide probes are covered, giving also an overview on the clinical investigations performed so far. The recent development of radiolabeled MG analogs, which are highly stabilized against enzymatic degradation in vivo, promises to have a high impact on the clinical management of patients with CCK2R expressing tumors in the near future.

Disorders of neural crest derivates in oncoradiological practice

Hundreds of articles discuss the imaging characteristics and molecular background of prominent gastrointestinal (GI) motility disorders and tumors of the peripheral nervous system, but according to our knowledge an article focusing on the classification and developmental background of these heterogeneous diseases is not to be found. Our aim is to give insight on the common features of several diseases and tumors, starting with their common source of origin, the neural crest (NC). The NC is a transient cell population of the embryo, which differentiates into several organs/structures of our body (sympathetic trunk, adrenal medulla). Although the incidence of the individual tumors of NC cells is not high by themselves, the summation of these incidences may be relevant in the daily routine. In the introduction we mention the most prominent developmental routes and molecular pathways of NC cells, which is crucial to understand the pathogenesis and the wide range of involved cell types from the colon to the adrenal gland. We summarized the most important, useful pathological findings and imaging techniques from the X-ray to the positron emission tomography—computed tomography (CT) in order to help the identification of these diseases. This article may help to better understand NC lineage and its unique, diverse role during ontogeny, which may influence the radiologists to change several convictions, or understand better the background and/or connections of a wide range of tumors and syndromes.

[Imaging of medullary thyroid carcinoma]

BACKGROUND

About 10% of thyroid cancers are medullary thyroid carcinoma (MTC) and can occur sporadically, familially and in the context of type II multiple endocrine neoplasia (MEN). Imaging plays a pivotal role in screening family members and in diagnosis.

DIAGNOSTIC METHODS

Diagnosis is based on ultrasound (US), thyroid scintigraphy, serum calcitonin and carcinoembryonic antigen (CEA) as well as fine needle biopsy. High-resolution US is the most important imaging method for locoregional staging, combined with computed tomography (CT) of the mediastinum. Positron emission tomography (PET-CT) using 18-F-DOPA is particularly suited for suspected occult metastases in case of rising tumor markers in serum.

FINDINGS AND COURSE OF DISEASE

Diagnosis is made based on cytologic findings in a hypoechoic, cold thyroid nodule, combined with an elevation of serum calcitonin and CEA. US is the most important imaging modality during routine follow-up. CT is indicated for suspected mediastinal, lung, or liver metastases. CT should be replaced by MRI as early as possible to prevent significant cumulative radiation doses over time.

RECENT CLINICAL DEVELOPMENTS

Although MTC is curable by surgery only, owing to its radio- and chemoresistance, the disease will often progress only slowly, and even patients with metastases will frequently survive 10 years or longer. For more aggressive variants and late symptomatic stages, targeted drugs that have the potential to indicate stabilization or even a partial remission of the disease are under clinical investigation or already approved.

Medullary Thyroid Carcinoma: An Update on Imaging

Medullary thyroid carcinoma (MTC), arising from the parafollicular C cells of the thyroid, accounts for 1–2% of thyroid cancers. MTC is frequently aggressive and metastasizes to cervical and mediastinal lymph nodes, lungs, liver, and bones. Although a number of new imaging modalities for directing the management of oncologic patients evolved over the last two decades, the clinical application of these novel techniques is limited in MTC. In this article, we review the biology and molecular aspects of MTC as an important background for the use of current imaging modalities and approaches for this tumor. We discuss the modern and currently available imaging techniques—advanced magnetic resonance imaging (MRI)-based techniques such as whole-body MRI, dynamic contrast-enhanced (DCE) technique, diffusion-weighted imaging (DWI), positron emission tomography/computed tomography (PET/CT) with 18F-FDOPA and 18F-FDG, and integrated positron emission tomography/magnetic resonance (PET/MR) hybrid imaging—for primary as well as metastatic MTC tumor, including its metastatic spread to lymph nodes and the most common sites of distant metastases: lungs, liver, and bones.

CT- and ultrasound-characteristics of hepatic lesions in patients with multiple endocrine neoplasia syndrome. A retrospective image review of 25 cases

Introduction

Liver metastases from neuroendocrine tumors in multiple endocrine neoplasia syndrome are common (75%) and significantly impairs the prognosis. Characterisation of liver lesions in these patients is challenging, as liver metastases are difficult to differentiate from benign liver lesions such as haemangioma.

Methods

In this study we aimed to characterize the radiological findings of hepatic metastases in MEN patients. The findings of contrast-enhanced CT were considered for the main diagnosis. We retrospectively evaluated 25 patients with MEN-syndrome (10 MEN1/ 15 MEN2) including 11 men and 14 women between 28–62 years of age.

Results

Liver metastases (48%, 12/25) and hemangioma (40%, 10/25) were the most common liver lesions among our patients. The most common primary tumors in our MEN1 and MEN2 patients with liver metastases were of pancreatic neuroendocrine tumor (70%, 7/10) und medullary thyroid carcinoma (100%, 15/15) origin, respectively. CT-characteristics were grouped into three main categories, depending on contrast dynamics. The majority of hepatic metastases (75%, 14/25) are presented as multiple lesions with a slow growth in an average 5 years of follow-up-period. We were able to find a common CT pattern and categorise these for each MEN-syndrome. Hepatic metastases in MEN1 presented commonly a blurred arterial enhancement with a low portal venous enhancement and less frequently a prominent enhancement in the arterial phase, which mimics the classical haemangioma. In MEN2 the liver metastases exhibited disseminated mixed hyper- and hypo-enhanced lesions in CT-scans. Moreover, lesion calcifications are pathognomonic in MEN2. The main limitation of this study is the missing histopathological confirmation in the majority of cases.

Conclusions

In this retrospective imaging study, we were able to categorise and find a common CT pattern for hepatic lesions in patients with MEN-syndrome. In order to differentiate these lesions sufficiently, a combination of a 3-phasic CT-scan with US is required. Other liver specific imaging modalities (MRI, CEUS, SMS-PET/CT) should complement the diagnosis in individual cases.

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.

Neuroendocrine Tumor Diagnosis and Management: 68Ga-DOTATATE PET/CT

OBJECTIVE

The purpose of this article is to provide a review of the use of ⁶⁸Ga tetraazacyclododecanetetraacetic acid-DPhe1-Tyr3-octreotate (DOTATATE) PET/CT, a functional imaging modality for assessment of well-differentiated neuroendocrine tumors (NETs). It has become the preferred imaging modality for initial diagnosis, selection of patients for peptide receptor radionuclide therapy, and localization of unknown primary tumors. The National Comprehensive Cancer Network guideline has added ⁶⁸Ga-DOTATATE PET/CT as an appropriate test in the management of NETs.

CONCLUSION

In combination with FDG PET/CT, ⁶⁸Ga-DOTATATE PET/CT can noninvasively assess tumor heterogeneity, especially in G2 and G3 NETs, for personalized management of patients.

Educational Case: Endocrine Neoplasm: Medullary Thyroid Carcinoma

Medullary thyroid cancer is a rare neuroendocrine tumor that arises the neural crest-derived parafollicular C cells and accounts for approximately 5% to 10% of thyroid cancers worldwide. These tumor can occur sporadically or as part of hereditary tumor syndromes, such as multiple endocrine neoplasia 2 and familial medullary thyroid cancer. The most common clinical presentation is a solitary thyroid nodule. The genetic defect in these disorders involves the RET proto-oncogene which is important for diagnosis of medullary thyroid cancer (including screening for hereditary medullary thyroid cancer) and for treatment guidance. This review summarizes the molecular basis and clinicopathologic features of medullary thyroid carcinoma.

High CEA levels in a case of resected colorectal cancer: delayed diagnosis of metachronous medullary thyroid cancer

Background

Carcinoembryonic antigen (CEA) is one of the most widely used tumor markers, and its value in the surveillance of post-operative colorectal cancer is well established. Fluorodeoxyglucose-positron emission tomography (FDG-PET) has been clinically used in colorectal cancer imaging including preoperative staging, evaluation of therapeutic response, detection of disease recurrence, and investigation of unexplained rising tumor markers.

Case presentation

We report a case of resected colorectal cancer presented with rising CEA levels in 5 years, and FDG-PET revealed no definitive evidence of recurrence except abnormal focal FDG uptake in the right thyroid lobe. However, fine needle aspiration cytology (FNAC) of the thyroid nodule showed negative for malignancy. Progressively rising CEA levels were noted over the following 5 years, but serial follow-up examinations did not find evidence of recurrence. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) was performed subsequently and again showed focal FDG uptake in the right thyroid lobe. This time, FNAC revealed positive for malignancy, in favor of medullary thyroid carcinoma (MTC). The patient underwent total thyroidectomy and modified radical neck dissection, and MTC with cervical nodal metastasis (pT3N1) was diagnosed. He had cervical lymph nodes recurrence 2 years later, which was resected.

Conclusions

This case reminded us that FDG-PET/CT may detect occult tumors resulting in CEA elevation other than colorectal cancer. Moreover, FNA has a higher false negative rate in detecting MTC than other forms of thyroid cancer. Repeat FNAC for the initial negative cytology result and measure of serum calcitonin for the early MTC detection could be more helpful to avoid the delay in MTC diagnosis.

Imaging and Screening of Hereditary Cancer Syndromes

There is a wide spectrum of mendelian disorders that predispose patients to an increased risk of benign as well as malignant tumors. Hereditary cancer syndromes are characterized by the early onset of diverse, frequently advanced malignancies in specific organ systems in multiple family members, posing significant challenges to diagnosis and management. A better understanding of the genetic abnormalities and pathophysiology that underlie these disorders has led to contemporary paradigms to screen, allowing early diagnosis, and has improved targeted therapies to aid in management. This article reviews select hereditary cancer syndromes with an emphasis on imaging-based screening and surveillance strategies.

68Ga-DOTATATE PET/CT in recurrent medullary thyroid carcinoma: a lesion-by-lesion comparison with 111In-octreotide SPECT/CT and conventional imaging

PURPOSE

The aim of this study was to prospectively compare the detection rate of ⁶⁸Ga-DOTATATE PET-CT with ¹¹¹In-octreotide SPECT-CT and conventional imaging (CI) in medullary thyroid carcinoma (MTC) patients with increased calcitonin (Ctn) levels but negative CI after thyroidectomy.

METHODS

Fifteen patients with raised Ctn levels and/or CI evidence of recurrence underwent ⁶⁸Ga-DOTATATE PET-CT, ¹¹¹In-octreotide SPECT-CT and CI. Histopathology, CI and biochemical/clinical/imaging follow-up were used as the reference standard. PET/CT, SPECT/CT and CI were compared in a lesion-based and organ-based analysis.

RESULTS

PET/CT evidenced recurrence in 14 of 15 patients. There were 13 true positive (TP), 1 true negative (TN), 1 false positive (FP) and no false negative (FN) cases, resulting in a sensitivity and accuracy of 100% and 93%. SPECT/CT was positive in 6 of 15 cases. There were 6 TP, 2 TN, 7 FN and no FP cases, resulting in a sensitivity of 46% and accuracy of 53%. CI procedures detected tumor lesions in 14 of 15 patients. There were 13 TP, 1TN, 1 FP and no FN cases with a sensitivity of 100% and accuracy of 93%. A significantly higher number of lesions was detected by PET/CT (112 lesions, p = 0.005) and CI (109 lesions, p = 0.005) in comparison to SPECT/CT (16 lesions). There was no significant difference between PET/CT and CI for the total number of detected lesions (p = 0.734). PET/CT detected more lesions than SPECT/CT regardless of the organ. PET/CT detected more bone lesions but missed some neck nodal metastases evidenced by CI. The number of lesions per region demonstrated by PET/CT and CI were similar in the other sites.

CONCLUSION

⁶⁸Ga-DOTATATE PET/CT is superior to ¹¹¹In-octreotide SPECT/CT for the detection of recurrent MTC demonstrating a significantly higher number of lesions. ⁶⁸Ga-DOTATATE PET/CT showed a superior detection rate compared to CI in demonstrating bone metastases.

Hepatic Lesions in a Cirrhotic Liver: Primary or Metastases?

Although prior studies showed that patients with cirrhosis have a lower risk of developing liver metastases, appropriate workup of incidental liver masses in cirrhotic liver is important for a correct diagnosis. Here we present a case of newly diagnosed liver cirrhosis with multifocal hepatic lesions, which was initially categorized as a LI-RADS (Liver Imaging Reporting and Data System) 5 lesions. Scintigraphy with 111In-pentetreotide (Octreoscan) indicated a suspected thyroid nodule, later confirmed to represent medullary thyroid carcinoma lesion. The most relevant imaging finding of this rare form of thyroid malignancy is reviewed in this presentation.

Epigenetic modulators of thyroid cancer

There are some well known factors involved in the etiology of thyroid cancer, including iodine deficiency, radiation exposure at early ages, or some genetic changes. However, epigenetic modulators that may contribute to development of these tumors and be helpful to for both their diagnosis and treatment have recently been discovered. The currently known changes in DNA methylation, histone modifications, and non-coding RNAs in each type of thyroid carcinoma are reviewed here.

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.

CT and MR imaging of thyroid carcinoma showing thymus-like differentiation (CASTLE): a report of ten cases

OBJECTIVE

To study the CT and MR imaging features of carcinoma showing thymus-like differentiation (CASTLE) and to raise awareness of this rare thyroid tumour.

METHODS

The imaging appearances of 10 CASTLE tumours confirmed by surgical pathology were retrospectively reviewed and correlated with clinical and histological findings.

RESULTS

Seven patients with newly diagnosed and three patients with recurrent tumours were identified (six males and four females). CASTLE tumours were commonly located in the lower neck between the inferior pole of the thyroid and the upper mediastinum. The average tumour size was 4.2 cm (range: 2.5-6 cm). On plain CT scans, most tumours were ill-defined nodular masses of uniform density. After enhancement, most cases showed mild enhancement, while heterogeneous enhancement could be seen in more than half the cases. On the MR images, tumours presented with homogeneous isointensity on T1 weighted images and they appeared to be slightly hyperintense on T2 weighted images. On post-contrast images, marked enhancement was seen in two patients, and heterogeneous enhancement was seen in three cases. Aggressive local infringements mainly included the ipsilateral strap muscle, tracheoesophageal groove area and tracheal wall. The specimens stained positively for CD5 and CD117, indicating thymic differentiation.

CONCLUSION

CASTLE has no characteristic imaging features when compared with other thyroid nodules, except for its unique location in the lower neck between the inferior pole of the thyroid and the upper mediastinum. CD5- and CD117-specific immunoreactivity is useful for diagnosis.

ADVANCES IN KNOWLEDGE

We reported 10 cases of CT and MR images illustrating the features of CASTLE, and we raised the level of awareness of this rare malignant thyroid tumour.

Osteopontin expression is correlated with differentiation and good prognosis in medullary thyroid carcinoma

BACKGROUND

Osteopontin (OPN) or secreted phosphoprotein 1 (SPP1) is a matricellular glycoprotein whose expression is elevated in various types of cancer and has been shown to be involved in tumourigenesis and metastasis in many malignancies, including follicular cell-derived thyroid carcinomas. Its role in C-cell-derived thyroid lesions and tumours remains to be established.

OBJECTIVE

The objective of this study is to clarify the role of OPN expression in the development of medullary thyroid carcinoma (MTC).

METHODS

OPN expression was analysed in a series of 116 MTCs by immunohistochemistry and by qPCR mRNA quantification of the 3 OPN isoforms (OPNa, OPNb and OPNc) in six cases from which fresh frozen tissue was available. Statistical tests were used to evaluate the relationship of OPN expression and the clinicopathological and molecular characteristics of patients and tumours.

RESULTS

OPN expression was detected in 91 of 116 (78.4%) of the MTC. We also observed high OPN expression in C-cell hyperplasia as well as in C-cells scattered in the thyroid parenchyma adjacent to the tumours. OPN expression was significantly associated with smaller tumour size, PTEN nuclear expression and RAS status, and suggestively associated with non-invasive tumours. OPNa isoform was expressed significantly at higher levels in tumours than in non-tumour samples. OPNb and OPNc presented similar levels of expression in all samples. Furthermore, OPNa isoform overexpression was significantly associated with reduced growth and viability in the MTC-derived cell line (TT).

CONCLUSION

The expression of OPN in normal C-cells and C-cell hyperplasia suggests that OPN is a differentiation marker of C-cells, rather than a marker of biological aggressiveness in this setting. At variance with other cancers, OPN expression is associated with good prognostic features in MTC.

Multimodal imaging with (18)F-FDG-PET/CT and (111)In-Octreotide SPECT in patients with metastatic medullary thyroid carcinoma

OBJECTIVE

The aim of our study was to determine the role of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) and indium-111 Octreotide single photon emission tomography ((111)In-Octreotide SPECT) in the evaluation of metastatic medullary thyroid carcinoma (MMTC).

METHODS

Twenty-five MMTC patients were retrospectively evaluated. All patients had undergone whole-body (18)F-FDG-PET/CT including 20 who had also undergone (111)In-Octreotide SPECT within a maximum interval of 6 weeks. Diagnostic contrast-enhanced computed tomography (CT) alone or as part of (18)F-FDG-PET/CT examination was performed in all patients.

RESULTS

Contrast-enhanced CT detected a total of 131 lesions including 79 enlarged lymph nodes and 14 bone lesions. (18)F-FDG-PET/CT visualized a total of 92 true positive lesions (SUVmax range 1.1-10.0, mean 4.0 ± 1.7) including 66 lymph nodes, 7 of which were not enlarged on CT, and 8 bone metastases. In the 20 patients studied with both techniques, a total of 64 and 46 true positive lesions were detected by (18)F-FDG-PET/CT and (111)In-Octreotide SPECT, respectively. In particular, (18)F-FDG uptake was found in 43 lymph nodes and in 7 bone metastases whereas (111)In-Octreotide uptake was detected in 27 lymph nodes and in 10 bone metastases.

CONCLUSIONS

In MMTC patients, (18)F-FDG-PET/CT provides a useful contribution mainly in evaluating lymph node involvement whereas (111)In-Octreotide SPECT can contribute to the detection and somatostatin receptor characterization especially of bone lesions.

Diagnosis and Management of Hereditary Thyroid Cancer

Thyroid cancers are largely divided into medullary (MTC) and non-medullary (NMTC) cancers , depending on the cell type of origin. Familial non-medullary thyroid cancer (FNMTC) comprises about 5-15% of NMTC and is a heterogeneous group of diseases, including both non-syndromic and syndromic forms. Non-syndromic FNMTC tends to manifest papillary thyroid carcinoma , usually multifocal and bilateral . Several high-penetrance genes for FNMTC have been identified, but they are often confined to a few or single families, and other susceptibility loci appear to play a small part, conferring only small increments in risk. Familial susceptibility is likely to be due to a combination of genetic and environmental influences. The current focus of research in FNMTC is to characterise the susceptibility genes and their role in carcinogenesis. FNMTC can also occur as a part of multitumour genetic syndromes such as familial adenomatous polyposis , Cowden's disease , Werner's syndrome and Carney complex . These tend to present at an early age and are multicentric and bilateral with distinct pathology. The clinical evaluation of these patients is similar to that for most patients with a thyroid nodule. Medullary thyroid cancer (MTC) arises from the parafollicular cells of the thyroid which release calcitonin. The familial form of MTC accounts for 20-25% of cases and presents as a part of the multiple endocrine neoplasia type 2 (MEN 2) syndromes or as a pure familial MTC (FMTC). They are caused by germline point mutations in the RET oncogene on chromosome 10q11.2. There is a clear genotype-phenotype correlation, and the aggressiveness of FMTC depends on the specific genetic mutation, which should determine the timing of surgery.

Serum chromogranin A is a useful marker for Japanese patients with pancreatic neuroendocrine tumors

Although chromogranin A (CGA) is a useful marker for pancreatic neuroendocrine tumors (pNET) in the West, its usefulness in Japanese populations is unclear. To assess this, we evaluated the serum CGA levels in 189 patients with various pancreatic diseases, including proven pNET (n = 69), pancreatic cancer (PC) (n = 50), chronic pancreatitis (CP) (n = 50) and autoimmune pancreatitis (AIP) (n = 20), and 112 normal controls (controls) using an ELISA kit. The mean CGA level of patients with pNET was significantly higher than any of the other groups (407.8 ± 984.6 ng/mL [pNET] vs 91.8 ± 101.8 ng/mL [PC], 93.6 ± 57.5 ng/mL [CP], 69.9 ± 52.4 ng/mL [AIP] and 62.5 ± 48.3 ng/mL [controls]). Limiting the analysis to patients not using proton pump inhibitors (PPI), the CGA level of patients with PC or CP was not significantly different compared with the controls. Discriminant analysis revealed that the best cut-off value of CGA to distinguish patients with pNET from the controls was 78.7 ng/mL, with a sensitivity and specificity of 53.6% and 78.6%, respectively. In patients with pNET, significant factors associating with elevated CGA levels were tumor classification, tumor size, and the presence of liver metastases in univariate analysis as well as PPI use and the presence of liver metastases in multivariate analysis. We show that CGA is a useful marker for diagnosing pNET in Japanese populations and for distinguishing patients with pNET from patients with other pancreatic diseases. The increased use of CGA in Japan will likely be a helpful tool in managing these patients, as found in the West.

Medullary-like hepatocellular carcinoma: an unusual histologic variant

OBJECTIVES

Due to differences in prognosis and management, it is important to subclassify hepatocellular carcinoma (HCC). We encountered an unusual case of HCC with features not typical of the previously described subtypes that was composed of a markedly cellular background consisting of plasma cells and lymphocytes.

METHODS

Review of the literature revealed a single prior case report describing a lesion with similar histology.

RESULTS

In contrast to the previous case report suggesting a less aggressive course and a lesion with increased apoptotic activity, our patient died as a result of his disease within 30 days of diagnosis. In this report, we compare the features of our case with the previously described lesion and use immunohistochemistry for cleaved caspase 3 to evaluate apoptosis and mismatch repair proteins to evaluate microsatellite instability.

CONCLUSIONS

This report is presented to increase awareness of this unusual lesion and because it raises questions regarding the previous claim suggesting a less aggressive clinical course.