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With the widespread use of 18F‐fluorodeoxyglucose positron emission tomography (FDG PET/CT) in the investigation and staging of cancers, incidental discovery of FDG‐avid thyroid nodules is becoming increasingly common, with a reported incidence in the range 1%–4% of FDG PET/CT scans. The risk of malignancy in an incidentally discovered FDG avid thyroid nodule is not clear due to selection bias in reported retrospective series but is likely to be less than 15%. Even in cases where the nodule is found to be malignant, the majority will be differentiated thyroid cancers with an excellent prognosis even without treatment. If, due to index cancer diagnosis, age and co‐morbidities, it is unlikely that the patient will survive 5 years, further investigation of an incidental FDG avid thyroid nodule is unlikely to be warranted. We provide a consensus statement on the circumstances in which further investigation of FDG avid thyroid nodules with ultrasound and fine needle aspiration might be appropriate. [ABSTRACT FROM AUTHOR]

Background: Prostate cancer patients, undergo imaging procedures, with [68Ga]Ga-PSMA-11 PET/CT (prostate-specific membrane antigen based positron emission tomography/computed tomography) utilized for primary and secondary staging. PSMA thyroid incidentalomas (PTI) are discovered in the thyroid gland while imaging prostate cancer patients with [68Ga]Ga-PSMA-11 PET/CT. Aims: The aim of the study was to determine the clinical significance of PTIs detected on [68Ga]Ga-PSMA-11 PET/CT. Another goal was to identify a possible threshold for the maximum standardized uptake value (SUVmax), above which a malignant growth could be suspected. Study design: A retrospective cross-sectional study. Methods: 769 patients with prostat cancer who underwent [68Ga]Ga-PSMA-11 PET/CT scans in the nuclear medicine department of a tertiary care hospital between January 2020 and December 2022 were retrospectively screened in this study. We analyzed 67 patients in whom PTI was detected. Patients who exceeded the inclusion criteria had their thyroid ultrasonography and ultrasonography -guided fine needle aspiration findings analyzed. Results: PTI was discovered in 67 patients (8%). 42 patients who met the inclusion and exclusion criteria were included in the study. Of the 4 malignant patients (9.5%) in the study population, 2 were classified as TIRADS 3 and 2 were classified as TIRADS 4. The cut-off SUVmax value was found to be 5.6. With 100% sensitivity and 47.37% specificity, a cutoff SUVmax of 5.3 was determined through receiver–operator characteristic analysis in order to predict malignant cytology. Conclusion: PTI is a significant clinical finding; most of diffuse and focal uptakes are frequently related to benign diseases. Each center should establish its own a possible SUVmax cut-off over which a malignant lesion should be suspected. [ABSTRACT FROM AUTHOR]

Abstract Follicular cell-derived thyroid carcinomas constitute the majority of thyroid malignancies. This heterogeneous group of tumours includes well differentiated, poorly differentiated, and undifferentiated forms, which have distinct pathological features, clinical behaviour, and prognosis. Positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose combined with computed tomography ([18F]FDG PET/CT) is an imaging modality used in routine clinical practice for oncological patients. [18F]FDG PET/CT has emerged as a valuable tool for identifying patients at high risk of poor clinical outcomes and for facilitating individualized clinical decision-making. The aim of this comprehensive review is to summarize current knowledge regarding the role of [18F]FDG PET/CT in primary diagnosis, treatment, and follow-up of follicular cell-derived thyroid carcinomas considering the degree of differentiation. Controversial issues, including significance of accidentally detected [18F]FDG uptake in the thyroid, the role of [18F]FDG PET/CT in the early assessment of response to molecular targeted therapies, and its prognostic value are discussed in detail.

Thirty to 50% of differentiated thyroid carcinomas include papillary thyroid microcarcinomas (mPTC). Most of these tumors remain clinically silent, have a bright prognosis and a disease-specific mortality

Introduction: Thyroid incidentalomas are often encountered during imaging performed for the workup of esophageal cancer. Their oncological significance is unknown. This study aimed to establish incidence and etiology of thyroid incidentalomas found during the diagnostic workup of esophageal cancer. Methods: All esophageal cancer patients referred to or diagnosed at the Amsterdam UMC between January 2012 and December 2016 were included. Radiology and multidisciplinary team meeting reports were reviewed for presence of thyroid incidentalomas. When present, the fluorodeoxyglucose-positron emission tomography/computed tomography (18FDG-PET/CT) or CT was reassessed by a radiologist. Primary outcome was the incidence and etiology of thyroid incidentalomas. Results: In total, 1,110 esophageal cancer patients were included. Median age was 66 years, most were male (77.2%) and had an adenocarcinoma (69.4%). For 115 patients (10.4%), a thyroid incidentaloma was reported. Two thyroidal lesions proved malignant. One was an esophageal cancer metastasis (0.9%) and one was a primary thyroid carcinoma (0.9%). Only the primary thyroid carcinoma resulted in treatment alteration. The other malignant thyroid incidentaloma was in the context of disseminated esophageal disease and ineligible for curative treatment. Conclusion: In this study, thyroid incidentalomas were only very rarely oncologically significant. Further etiological examination should only be considered in accordance with the TI-RADS classification system and when clinical consequences are to be expected. [ABSTRACT FROM AUTHOR]

Thirty to 50% of differentiated thyroid carcinomas include papillary thyroid microcarcinomas (mPTC). Most of these tumors remain clinically silent, have a bright prognosis and a disease-specific mortality <1%. Surgery has been recommended as first line-treatment by current guidelines, the standard treatment being lobectomy. However, surgery has some drawbacks, including potential recurrent laryngeal nerve paralysis, hypothyroidism, hypoparathyroidism, in -patient basis hospital stay, lifelong medication, scarring of the neck, and general anesthesia related risks. Moreover, elderly patients who present severe comorbidities, could be ineligible for surgery, and others may refuse invasive surgery. Another option supported by the American Thyroid Association is active surveillance. This option can be considered as unattractive and difficult to accept by European patients, as there is a 2–6% risk of disease progression. Percutaneous image-guided thermal ablation has been successfully applied in the treatment of liver and lung tumors in the 1990s and 2000s; and has recently been proposed as an alternative to surgery in patients presenting with thyroid diseases. This minimally invasive treatment has similar efficacy, fewer complications, better quality of life and cosmetic outcomes than surgery. We report herein two cases of radiofrequency ablation of mPTC and T2 PTC in elderly patients who were ineligible for surgery. [ABSTRACT FROM AUTHOR]

Purpose. The purpose of this study is to determine the clinical significance of incidental thyroid 18F-FDG PET/CT uptake in oncology patients with the focus achieving the most appropriate management of this challenging situation. Materials and method. Two thousand five hundred and eighty 18F-FDG PET/CT studies performed at our institute in the past 4 years were retrospectively reviewed. Patients with incidental FDG uptake in the thyroid gland were further analysed. Results. The prevalence of incidental FDG uptake in thyroid gland was 7.6% (129 patients). 26 patients (20.1%) had diffuse 18F-FDG PET/CT uptake, 103 patients (79.1%) had nodular uptake in thyroid gland. All diffuse uptake patients who were further examined diagnosed to be a benign condition. 53 patients in the nodular uptake group were further examined and the final histopathology examinations revealed an 18.8% malignancy rate. SUV max values ranged from 2 to 21.8 with a significant highness in malignant lesions. Conclusion. 18F-FDG PET/CT uptake in the thyroid gland may be diffuse or nodular. Diffuse uptake needs no further examination as it usually accompanied by benign thyroid disorders. Patients with nodular uptake whose general condition is good should be further examined due to high rates of malignancy. [ABSTRACT FROM AUTHOR]

Background: A thyroid incidentaloma (TI) is an unexpected, asymptomatic thyroid lesion discovered during the investigation of an unrelated condition. The aim of the present study is to examine the incidence of 18Fluorodeoxyglucose (FDG)-positron emission tomography (PET) TI, the associated management strategies and the outcomes in a tertiary cancer referral center. Methods: This study involves a retrospective cohort study of 1003 patients with TI found on 18FDG-PET/CT scans performed between January 2010 and January 2020 for a nonthyroidal malignancy. The Kaplan–Meier method was used for survival analyses in patients concerning an underlying malignancy, with a prevalence of 5% or higher in this cohort. Logistic- and cox regression analyses were performed to analyze predictors of thyroid malignancy and mortality. A propensity score weighted method was used to control for baseline differences between the intervention (additional TI diagnostics) and control (no TI diagnostics) group. Results: FDG-positive TI occurred in 1.9% (1003/52,693) of the oncologic 18FDG-PET/CT scans performed in our center. Thyroid surgery was performed in 47 patients (6%) and a thyroid malignancy was detected in 31 of them, which is 66% of those who had an operation and 4% of all patients. During the follow-up (median 6 years), 334 deaths (42%) related to different types of cancer (38%) or other causes (4%) were observed. One patient died from medullary thyroid cancer. In multivariate analysis adjusted for age, gender and the type- and stage of nonthyroidal malignancy, were independent predictors of survival (P < .05). Conclusions: The incidence of TI in this tertiary cancer referral center was comparable to current literature. Further thyroid workup was performed in less than half of the patients, and only a minority of patients underwent thyroid surgery. Since only one patient died from thyroid cancer, the strategy to withhold from thyroid diagnostics and treatment seems valid for most TI. Active thyroid treatment might benefit a subgroup of patients in whom the primary nonthyroidal malignancy is successfully treated or presumably stable. A wait-and-see policy with ultrasound follow-up could be an alternative strategy. These considerations should be part of the shared decision making in cancer patients with a TI. [ABSTRACT FROM AUTHOR]

Background: [18F]-Fluorodeoxyglucose (FDG)-avid thyroid lesions incidentally detected on positron emission tomography/computed tomography (PET/CT) scans represent a tumor lesion in about 30% of cases. The present study evaluated the ability of PET metrics and radiomics features to predict final diagnosis of [18F]FDG thyroid incidentalomas (TIs). Methods: A total of 104 patients with 107 TIs were retrospectively studied; 30 nodules (28%) were diagnosed as malignant. After volumetric segmentation of each thyroid lesion, metabolic tumor volume (MTV), total lesion glycolysis (TLG), standardized uptake values (SUVs), and metabolic heterogeneity were estimated, and 107 radiomics features were extracted following a standard protocol. Results: MTV, TLG, SUVmax, SUVmean, and SUVpeak among functional PET parameters, and gray-level co-occurrence matrix (GLCM)_InverseDifferenceMoment, shape_Sphericity, GLCM_SumSquares, firstorder_Maximum2DDiameterSlice, firstorder_Energy, and GLCM_Contrast among nonredundant radiomics features, showed significantly different values between malignant and benign TIs (Mann–Whitney U-test, p < 0.01 for all). Univariate logistic regression revealed that these parameters demonstrated good ability to predict final diagnosis of TIs (p < 0.02 for all). Shape_Sphericity was the best predictor classifying 82% of TIs correctly (p < 0.0001). Only TLG, SUVmax, and shape_Sphericity retained significance (p < 0.0001) by multivariate analysis. Malignant lesion prevalence increased from 7% to 100% in accordance with the number (score, 0–3) of the three positive parameters present (χ2 trend, p < 0.0001). A score of 0 excludes malignant TIs with a negative predictive value of 93%, while a score of 3 predicted malignancy with a positive predictive value of 100%. Conclusions: PET metrics and radiomics analysis can improve identification of [18F]FDG-avid TIs at high risk of malignancy. A model based on TLG, SUVmax, and shape_Sphericity may allow prediction of a final diagnosis, providing useful information for the management of TIs. [ABSTRACT FROM AUTHOR]

Background: We performed a systematic review of the literature to provide an overview of the application of PET-based radiomics of [18F]FDG-avid thyroid incidentalomas and to discuss the additional value of PET volumetric parameters and radiomic features over clinical data. Methods: The most relevant databases were explored using an algorithm constructed based on a combination of terms related to our subject and English-language articles published until October 2021 were considered. Among the 247 identified articles, 19 studies were screened for eligibility and 11 met the criteria, with 4 studies including radiomics analyses. Results: We summarized the available literature based on a study of PET volumetric parameters and radiomics. Ten articles provided accurate details about volumetric parameters and their prospective value in tumour assessment. We included the data provided by these articles in a sub-analysis, but could not obtain statistically relevant results. Four publications analyzed the diagnostic potential of radiomics and the possibility of creating precise predictive models, their corresponding quality score being assessed. Conclusions: The use of PET volumetric parameters and radiomics analysis in patients with [18F]FDG-avid thyroid incidentalomas outlines a great prospect in diagnosis and stratification of patients with malignant nodules and may represent a way of limiting the need for unnecessary invasive procedures; however, further studies need to be performed for a standardization of the method.

Purpose: The aim of this study was to evaluate the ability of 18F-FDG PET/CT texture analysis to predict the exact pathological outcome of thyroid incidentalomas. Methods: 18F-FDG PET/CT images between March 2010 and September 2018 were retrospectively reviewed in patients with focal 18F-FDG uptake in the thyroid gland and who underwent fine needle aspiration biopsy from this area. The focal uptake in the thyroid gland was drawn in 3D with 40% SUVmax threshold. Features were extracted from volume of interest (VOI) using the LIFEx package. The features obtained were compared in benign and malignant groups, and statistically significant variables were evaluated by receiver operating curve (ROC) analysis. The correlation between the variables with area under curve (AUC) value over 0.7 was examined; variables with correlation coefficient less than 0.6 were evaluated with machine learning algorithms. Results: Sixty patients (70% train set, 30% test set) were included in the study. In univariate analysis, a statistically significant difference was observed in 6 conventional parameters, 5 first-, and 16 second-order features between benign and malignant groups in train set (p < 0.05). The feature with the highest benign-malignant discriminating power was GLRLMRLNU (AUC:0.827). AUC value of SUVmax was calculated as 0.758. GLRLMRLNU and SUVmax were evaluated to build a model to predict the exact pathology outcome. Random forest algorithm showed the best accuracy and AUC (78.6% and 0.849, respectively). Conclusion: In the differentiation of benign-malignant thyroid incidentalomas, GLRLMRLNU and SUVmax combination may be more useful than SUVmax to predict the outcome. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the malignancy rate of focal thyroid incidentaloma (fTI) in a population of patients undergoing a 18F-fluorodeoxyglucose positron emission tomography–computed tomography (FDG PET–CT) for a non-thyroid purpose. Design: We conducted a prospective cohort study from January 2013 to November 2014. All consecutive patients referred for a FDG PET–CT were prospectively screened. Patients with known neoplastic thyroid disease were excluded from the analysis. All patients presenting one or more fTI and who accepted to benefit from a complementary thyroid ultrasonography (US) were included and managed according to the French endocrine society consensus. Prevalence of fTI in our population and malignancy rate was assessed. Results: During the inclusion period, 10,171 patients were referred for a FDG PET–CT in our center. Fifty-three patients presenting a known thyroid disease were excluded. Among the remaining 10,118 patients, 127 (1.3%) with 131 fTI were individualized. US could not be performed in 37 patients. The remaining 90 patients (92 fTI) were explored by US ± fine-needle aspiration biopsy (FNAB). US results demonstrated a nodule aspect in 80 cases of which 60 benefited from FNAB. Nineteen of 92 fTI underwent surgery with 10 malignant lesions among the 60 patients performing both US and FNAB. Conclusion: The prevalence of fTI discovered on FDG PET–CT in our population was 1.3% with 10 malignant lesions among the 60 patients performing both US and FNAB.

Objective: The aim of the present study was to evaluate the prevalence of thyroid lesions detected by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) incidentally, determine malignancy risk and its relationship with maximal standardized uptake value (SUVmax) and FDG uptake pattern. Methods: Between February 2009 and February 2014, a total of 12713 patients underwent 18F-FDG PET/CT. Incidental thyroid uptake was seen in 710 patients and further diagnostic evaluation was performed on 147 patients with focal or diffuse FDG uptake. The 18F-FDG PET/CT findings of these patients and their association with malignancy were retrospectively reviewed. Results: The prevalence of thyroid incidentalomas detected by 18F-FDG PET/CT was 5.6% (710/12713). Of the 147 patients who underwent biopsy or thyroid surgery, histology was benign in 99 and malign in 48 patients. The malignancy risk of incidental thyroid lesions was calculated as 32.7% (48/147). The median SUVmax was 2.9 (0.6–27.4) in benign group, whereas 11.8 (2.4–72.9) in malign group and the difference between these groups was statistically significant (p

Thyroid incidentalomas (TIs) are being frequently detected on positron emission tomography (PET) scan. The risk of malignancy in these focal hot spots is substantially high as compared to incidentalomas detected on ultrasonography (USG)/magnetic resonance imaging/computed tomography (CT). Majority of the studies on the prevalence of TIs in PET and the risk of malignancy in them are retrospective and have had varied results. Very few prospective studies are available and very few Indian studies have been done on the subject. Hence, this study was undertaken to evaluate the clinical significance of TIs detected on fluorodeoxyglucose (FDG)-PET scan. The study included all patients undergoing FDG-PET scan for nonthyroid illness from October 2015 to October 2016. Twenty-three consecutive patients detected to have focal TI (FTI) were prospectively evaluated with detailed history and clinical examination, serum thyroid-stimulating hormone, total T4 and total T3 levels, USG neck, fine-needle aspiration cytology (FNAC), and surgery when indicated. The prevalence of FTI was 2.26%. Out of the 23 FTI cases, 19 patients agreed to undergo further evaluation and malignancy was detected in 5 patients (all papillary carcinomas) making a risk of malignancy of 26.3%. There was no significant correlation between CT attenuation characteristics and size of benign and malignant PETomas or between the maximum standardized uptake value (SUVmax) of benign and malignant PETomas. Hence, the risk of malignancy in thyroid PETomas is substantially high and warrants USG-guided FNAC and further work-up. Their SUVmaxvalues, size, and CT attenuation characteristics do not contribute in differentiating benign from malignant lesions. [ABSTRACT FROM AUTHOR]

Purpose: Characterization of thyroid nodules is crucial to propose surgical intervention for histological verification. Cervical ultrasound potentially combined with fine needle aspiration is recommended, and fluorocholine positron emission tomography (FCH-PET), commonly used in prostatic cancers, has been evaluated in the diagnosis of thyroid cancers in recent publications. Methods: We present two cases of patients with multinodular thyroid and primary hyperparathyroidism. The preoperative assessment consisted of an ultrasound, a MIBI scintigraphy and an FCH-PET in favor of a parathyroid adenoma. Results: The imaging examinations pointed to a diagnosis of a parathyroid adenoma. In both cases, papillary thyroid carcinoma, missed by FCH-PET, was discovered incidentally at a distance from the parathyroid adenoma during the surgical procedure. Conclusions: These are the first descriptions of thyroid papillary carcinoma without preoperative FCH-PET identification. These clinical cases are contrary to recent publications showing a benefit of this examination in the diagnosis of thyroid cancers. [ABSTRACT FROM AUTHOR]

Introduction: Thyroid incidentaloma is defined as a thyroid lesion incidentally and newly detected by imaging techniques performed for an unrelated purpose and especially for a non-thyroid disease. Aim of this review is to evaluate the prevalence and clinical significance of focal incidental radiolabelled choline uptake in the thyroid gland (CTI) revealed by PET or PET/CT. Methods: A comprehensive computer literature search of the PubMed/MEDLINE, Scopus, and Embase databases was conducted to find relevant published articles about the prevalence and clinical significance of CTIs detected by PET or PET/CT in patients studied for other oncologic purposes. Results: Fifteen articles (14 case reports, one retrospective study on a larger population sample) were included in the systematic review. Considering the case reports, 7/14 CTIs were benign and 7/14 malignant. In the retrospective study on a larger population sample, 14/15 CTIs which underwent further investigations were benign. Conclusion: Despite very rare but probably underestimated, CTIs frequently signal in the presence of unexpected lesions in the thyroid that differ from the indicated reason for which the patient was initially scanned, and the risk of malignancy is not negligible. [ABSTRACT FROM AUTHOR]

Aim Of the Study: While the rate of thyroid incidentaloma detected on positron emission tomography (PET) was reported as 4%, the malignancy rate was 14%-50%. We evaluated the thyroid nodules which were detected by PET-computerized tomography (CT) in cancer patients and analyzed the pathological results of those thyroid nodules diagnosed by fine needle aspiration biopsy (FNAB) and their correlation with the maximum standardized uptake (SUVmax) value and PET imaging features.Materials and Methods: FNAB were performed for 40 thyroid incidentalomas. We analyzed the relationship between the histopathological findings and radiological features by Pearson's correlations and Chi-square-Fisher's exact tests to evaluate the factors associated with SUVmax.Results: The median SUVmax values were 5.4 for thyroid nodules. Totally, 14 malignancies were detected by FNAB (35%).The sensitivity and specificity of SUVmax value for diagnosis of malignancy were 87.5% and 52%, respectively. Positive and negative predictive values were 36.8% and 92.8%. The most common malignant and benign pathologies were classic variant papillary carcinoma and benign colloidal nodule. The median SUVmax was the higher in colon cancer thyroid metastasis and oncocytic neoplasia (SUVmax 14.5 and 13.6, respectively). Histopathological type was not related with nodule size but positively associated with categorical SUVmax(r = 0.318, P = 0.04) and negatively correlated with both the density of the thyroid nodule in PET-CT (r = -0.0042, P = 0.01) and density of nodule in ultrasound (USG) (r = -0.305, P = 0.05). Margin of the thyroid nodule in USG (P = 0.007) and internal component of the nodule in PET (P = 0.03) were found to be important factors to differentiate benign or malignant lesion.Conclusion: If the thyroid nodule is detected with flouro-2-deoxy-D-glucose uptake, to differentiate benign nodule from malignant, cytological examination is noteworthy to diagnose the more aggressive type of thyroid nodule and also thyroid metastasis from primary cancer. [ABSTRACT FROM AUTHOR]

The thyroid gland is often involved in the development of neoplastic diseases, including lymphoproliferative disorders. The aim of this paper is to provide a comprehensive overview of the multiple interactions between lymphoma and thyroid. Through an extensive research among the literature, the relationship between lymphomas and thyroid can be established at various levels, and the possible interconnections are here summarized in 5 points: (1) the greater risk of lymphoma development in some thyroid diseases; (2) the primary thyroid lymphoma, with focus on issues related to the diagnosis, differential diagnosis, and treatment; (3) the incidence of thyroid involvement in primitive nodal lymphomas or in extranodal lymphomas of the other sites; (4) thyroid changes after treatment of lymphoma, in relation to the effects of radiation therapy and immuno-chemotherapy; (5) the incidental findings of thyroid changes, on imaging, in patients with lymphoma, without a direct involvement of the gland in malignant disease. In conclusion, issues that until now have been dealt with separately will therefore be analyzed in a unique paper, allowing a global view of the topic and emphasizing the need of a multidisciplinary approach. Future learning areas in this topic mainly relate to rapidly increasing the knowledge of imaging studies together with expanding the armamentarium of novel biological and targeting agents in lymphoma patients. [ABSTRACT FROM AUTHOR]

Objective: The purpose of the current study is to examine the incidence and clinical significance of unexpected focal uptake of 18F-fluorodeoxyglucose (18F-FDG) on positron emission tomography/computed tomography (PET/CT) in the thyroid gland of oncology patients, the maximum standardized uptake value (SUVmax) of benign and malignant thyroid incidentalomas in these patients, and review the literature. Methods: Seven thousand two hundred fifty-two 18F-FDG PET/CT studies performed over four years, were retrospectively reviewed. Studies with incidental focal 18F-FDG uptake in the thyroid gland were further analyzed. Results: Incidental focal thyroid 18F-FDG uptake was identified in 157 of 7252 patients (2.2%). Sufficient follow-up data (>12 months) were available in 128 patients, of whom 57 (45%) had a biopsy performed and 71 had clinical follow-up. Malignancy was diagnosed in 14 of 128 patients (10.9%). There was a statistically significant difference between the median SUVmax of benign thyroid incidentalomas (SUVmax 4.8) vs malignant (SUVmax 6.3), but the wide range of overlap between the two groups yielded no clinically useful SUVmax threshold value to determine malignancy. Conclusion: 18F-FDG positive focal thyroid incidentalomas occurred in 2.2% of oncologic PET/CT scans, and were malignant in 10.9% of 128 patients. This is the lowest reported malignancy rate in a North American study to date, and significantly lower than the average malignancy rate (35%) reported in the literature. Invasive biopsy of all 18F-FDG positive thyroid incidentalomas, as recommended by some studies, is unwarranted and further research to determine optimal management is needed. There was no clinically useful SUVmax cut-off value to determine malignancy and PET/CT may not be a useful imaging modality to follow these patients conservatively. [ABSTRACT FROM AUTHOR]

Key Clinical Message Thyroid incidentaloma is defined as a new identified thyroid lesion occasionally detected during imaging studies. Incidence of thyroid incidentalomas is relatively rare in patients with lymphoma. Because of high rate of malignancy, these lesions with high intensity focal 18 FDG uptake detected on positron emission tomography with computed tomography ( PET/ CT) should undergo to biopsy regardless of size. [ABSTRACT FROM AUTHOR]

Thyroid nodules are common in dogs and are increasingly likely to be detected with the increased use of advanced imaging modalities. An unsuspected, nonpalpable, asymptomatic lesion, defined as a thyroid incidentaloma, may be discovered on an imaging study unrelated to the thyroid gland. The objective of this single-center cross-sectional study was to assess the prevalence and computed tomography (CT) characteristics of incidental and nonincidental thyroid tumors in a large population of dogs, using prospective recruitment of patients undergoing CT examination for various reasons during the period of 2005-2015. Unilateral or bilateral thyroid masses were detected in 96/4520 dogs (prevalence, 2.12%; 95% confidence interval [CI], 1.70-2.54%). Seventy-nine (82.3%) lesions were malignant and 17 (17.7%) were benign. Masses were discovered incidentally in 34/96 dogs (overall prevalence of incidentaloma, 0.76%; 95% CI, 0.51-1.02), and 24 (70.6%) of these 34 masses were thyroid carcinomas. Among the CT variables assessed, mineralization, vascular invasion, and tissue invasion were detected only in malignant tumors. Intratumoral vascularization was significantly associated with the presence of thyroid malignancy ( P < 0.001). Although incidental thyroid nodules in dogs are relatively rare, they are often malignant. Findings indicated that the neck should be thoroughly assessed in middle-aged and old patients undergoing body CT for various reasons. Thyroid nodules detected incidentally on CT should be sampled to avoid missing thyroid cancer. [ABSTRACT FROM AUTHOR]

Background: Thyroid incidentalomas (TI) are highly prevalent asymptomatic thyroid nodules with ultrasound as the best imaging modality for their detection and characterization. Although they are mostly benign, potential for malignancy is up to 10-15%. In sub-Saharan Africa little data exists on the prevalence and risk categorization of TI. The aim of this study was to determine the prevalence and ultrasound characteristics of non-palpable thyroid incidentalomas among adults in sub-Saharan setting. Methods: A cross sectional study was carried out between March and August 2015, at two university teaching hospitals. Sampling was consecutive and included all adults aged ≥ 16 years, presenting for any ultrasound other than for the thyroid, with no history or clinical signs of thyroid disease, and no palpable thyroid lesion. Ultrasound was done using 4 to 11 MHz linear probes. Subjects with diffuse thyroid abnormalities were excluded. Variables studied were age, gender, thyroid volume, ultrasound characteristics of thyroid nodules, TIRADS scores. Differences were considered statistically significant for p-value < 0.05. Results: The prevalence of TI was 28.3% (126 persons with TI /446 examined). This prevalence was 46.2% in population ≥ 61-year-old; 6.3% in population ≤ 20-year-old; 33.3% for females and 18.4% for males (p < 0.001). Of the 241 TI found, 49.4% were cysts, 33.6% solid, 17.0% mixed; 37.8% <5 mm and 22% >10 mm. Solid TI were mainly hyperechoic (42.0%), 3/81 were markedly hypoechoic. Sixty-nine out of 126 persons with TI (54.8%) had at least two nodules. Solitary nodules were predominant in the age group ≤20 years. Of 241 TI, 129 (53.5%) were classified TIRADS 2, 81 (33.6%) TIRADS 3, 25 (10.4%) TIRADS 4A, 6 (2.5%) TIRADS 4B, and none TIRADS 5. Characteristics associated with increased risk of malignancy where mostly founded on solid nodules (p < 0.000) and nodules larger than 15 mm (p < 0.001). Conclusion: Thyroid incidentalomas were very frequent with a prevalence of 28.3% and potential risk of malignancy in 12.9%. Prevalence had a tendency to increase with age and in female. Cystic nodules were the most prevalent. Potential for malignancy would be increased for larger and solid nodules. [ABSTRACT FROM AUTHOR]

Background: Positron emission tomography (PET) forms an integral part in work-up and follow-up of various malignancies. With the increased use of PET in oncology, finding of an incidental focal thyroid uptake (incidentaloma) is not unusual and presents a diagnostic challenge.Aim: The aim of the following study is to evaluate the frequency and radio-pathologic correlation of focal 18-fluoro deoxyglucose uptake (FDG) on PET within the thyroid from a large series.Materials and Methods: Retrospective review of 37,000 consecutive patients who underwent FDG-PET at tertiary cancer center in India. Radiological, pathological, PET scan and follow-up details were evaluated. Statistical analyzes were carried out using Mann Whitney test and Pearson correlation.Results: Abnormal thyroid uptake was seen in 78 (0.2%) patients. Nearly 61 (0.16%) scans had focal and 17 (0.04%) had diffuse FDG uptake. A total of 57 patients with focal uptake were available for further evaluation. No further evaluation was done in 24 (42.1%) patients who had advanced index malignancy. Of the remaining 33 patients 26 were benign and seven were a cause for concern (four primary thyroid cancers, one follicular neoplasm with hurthle cell change and two metastatic cancers). There was no significant correlation in Standardized uptake value (SUV) max of benign and malignant lesion (P = 0.5 on Mann Whitney) or size (r = 0.087 Pearson correlation co-efficient P= 0.667).Conclusion: Incidence of PET incidentaloma is low in this large cohort of Indian patients. Nearly 27% of focal incidentaloma were malignant. There was no correlation between the SUVmax, size and malignancy. [ABSTRACT FROM AUTHOR]

Introduction: The expanding use of 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) has resulted in an increased frequency of incidentally discovered areas of FDG uptake within the thyroid gland. In these incidentalomas, high malignancy rates are reported. The study aimed, on the one hand, to determine the prevalence in our setting of thyroid incidentalomas in patients with no previous history of thyroid cancer undergoing an FDG PET-CT as well as the risk of malignancy and, on the other hand, to evaluate the usefulness of the maximum standard uptake value (SUVmax) for detecting thyroid cancer., Material and Methods: The FDG PET-CT scans performed at our hospital between June 2013 and December 2020 were retrospectively reviewed. In those incidentalomas with sufficient additional investigation, a diagnosis of benign or malignant was established based on the complementary tests., Results: From the 21,594 PET-CT scans performed, 398 (1.8%) patients had an incidental FDG uptake, either focal (n=324) or diffuse (n=74). Among incidentalomas with further investigation, the rate of malignancy was higher in patients with focal FDG uptake than in those with diffuse uptake (26.5% versus 4%, respectively, p<0.05). The SUVmax value was significantly lower in benign focal lesions (5.7 [range: 2.3-66] than in malignant ones 10.6 [range: 3.1-51.2]; p<0.05). Nearly a quarter of malignant diagnoses (23.3%) were related to potentially aggressive tumours., Conclusion: The high rate of malignant tumours found among PET-CT incidentalomas and the high proportion of aggressive tumours demonstrate the need for a standardised approach in the investigation of incidental focal FDG uptake in the thyroid gland., (Copyright © 2022 SEEN and SED. Published by Elsevier España, S.L.U. All rights reserved.)

Background: It is well known that thyroid nodules are common among the general population. Despite the fact that only 4-8% are clinically detectable, a higher percentage ranging between 13-67% are identified with ultrasonography. Many studies have shown that malignancy can be detected in 5% of these nodules irrespective of their size. Nowadays, total thyroidectomy seems to be the most appropriate operation, even for benign thyroid diseases. We conducted this prospective study in order to assess the true incidence of occult thyroid cancer in benign thyroid disease specimens and explore any associated factors. Finally, we wanted to appraise whether total thyroidectomy is indeed justified based on these grounds. Materials and methods: From March 2010 to March 2014, we operated on 114 patients for benign thyroid pathology; the patients had a mean age of 52.24 years (17-81 years). Thirty patients were eventually found to have occult cancer (19 microcarcinomas and 11 macrocarcinomas).We compared the patients with and without cancer in order to determine any predictive factors. Results: Only the underlying histology was found to be related to the presence of cancer. Patients with cancer had a higher than expected percentage of Hashimoto thyroiditis while patients without cancer were found to have a greater than anticipated percentage of nodular hyperplasia. None of the other quantitative or qualitative factors were found to be a significant predictor of cancer. Conclusion: After performing a proper workup as indicated by the guidelines, a high risk for occult thyroid cancer still remains (at least in the Greek population), which justifies the selection of total thyroidectomy for the management of benign thyroid pathologies. Only the underlying histology is associated with the presence of cancer since Hashimoto thyroiditis seems to be a risk factor. [ABSTRACT FROM AUTHOR]

Aims Increasing use of 18F-Fluorodeoxy glucose (FDG) Positron Emission Tomography Computed Tomography (PET CT) has resulted in an increased frequency of incidentally discovered areas of focally increased FDG uptake within the thyroid gland – thyroid incidentalomas. We aimed to compare radiological characteristics of thyroid incidentalomas with cytology, histology and ultrasound findings. Materials and methods We examined all FDG PET CT scan reports for all patients undergoing this investigation over a 6 year period in a single tertiary cancer centre. All PET CT scans followed an agreed proforma allowing reports mentioning “thyroid” to be identified. Reports commenting on a positive finding within the thyroid gland were investigated further manually. Incidental mentions of thyroid with no underlying abnormality were discounted from analysis. Results In the study period, 7221 patients underwent FDG PET CT scanning in our unit. Within this group 75 (1%) showed diffuse FDG uptake and 81 (1.1%) showed focal uptake (thyroid incidentalomas). Only 30 patients (37%) with incidentalomas had further investigation and malignancy rate was 23% (7/30). Median Standardised Uptake Values (SUV) in malignant lesions was 9.9 (range 3.5–17.8) whilst in benign lesions and diffuse lesions it was 5.4 (2.8–32) and 4.2 (2.1–25.6) respectively ( p = 0.0013, Kruskal Wallis). Conclusion There remains a need to develop a standardised approach to the investigation and management of thyroid incidentalomas discovered on FDG PET CT scanning. Up to 1 in 4 of these patients will harbour thyroid malignancy. [ABSTRACT FROM AUTHOR]

Purpose: Our aim was to investigate the association between F-fluorodeoxyglucose (FDG) uptake and event-free survival in patients in whom a differentiated thyroid cancer (DTC) was detected by F-FDG positron emission tomography (PET)/CT. Methods: Among 884 focal F-FDG PET thyroid incidentalomas referred to our 4 Nuclear Medicine Departments, we investigated 54 patients in whom a DTC was confirmed and a clinical follow-up was available. The ratio between maximum standardized uptake value (SUV) of DTC and SUV of the liver (SUV ratio) was recorded for each scan. All patients underwent total thyroidectomy and I remnant ablation. After a median follow-up of 39 months we assessed the outcome. The association between disease persistence/progression, F-FDG uptake and other risk factors (T, N, M and histological subtype) was evaluated through univariate and multivariate analyses. Results: Of the 54 patients, 39 achieved complete remission. The remaining 15 showed persistence/progression of disease. High F-FDG uptake, i.e. SUV ratio ≥3, showed a low positive predictive value (48 %). Low F-FDG uptake (SUV ratio < 3) displayed a high negative predictive value (93 %). The median of SUV ratios in T1-T2 (2.2), in M0 (2.7) and in non-virulent subtypes (2.7) were significantly lower ( p < 0.03) than in T3-T4 (5.0), M1 (7.3) and virulent subtypes (6.0). Kaplan-Maier analysis showed a significant association between high F-FDG uptake and disease persistence/progression ( p = 0.001). When we adjusted risk estimates by using a multivariate Cox model, only T ( p = 0.05) remained independently associated with disease persistence/progression. Conclusion: An intense F-FDG uptake of the primary DTC is associated with persistence/progression of disease. However, when all other prognostic factors have been taken into account, F-FDG uptake does not add further prognostic information. [ABSTRACT FROM AUTHOR]

Thyroid incidentalomas are common findings during imaging studies including F-fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) for cancer evaluation. Although the overall incidence of incidental thyroid uptake detected on PET imaging is low, clinical attention should be warranted owing to the high incidence of harboring primary thyroid malignancy. We retrospectively reviewed 2,368 dual-time-point F-FDG PET/CT cases that were undertaken for cancer evaluation from November 2007 to February 2009, to determine the clinical impact of dual-time-point imaging in the differential diagnosis of thyroid incidentalomas. Focal thyroid uptake was identified in 64 PET cases and final diagnosis was clarified with cytology/histology in a total of 27 patients with F-FDG-avid incidental thyroid lesion. The maximum standardized uptake value (SUVmax) of the initial image (SUV1) and SUVmax of the delayed image (SUV2) were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1 (i.e., RI = [SUV2 - SUV1]/SUV1 × 100). These indices were compared between patient groups that were proven to have pathologically benign or malignant thyroid lesions. There was no statistically significant difference in SUV1 between benign and malignant lesions. SUV2 and RI of the malignant lesions were significantly higher than the benign lesions. The areas under the ROC curves showed that SUV2 and RI have the ability to discriminate between benign and malignant thyroid lesions. The predictability of dual-time-point PET parameters for thyroid malignancy was assessed by ROC curve analyses. When SUV2 of 3.9 was used as cut-off threshold, malignancy on the pathology could be predicted with a sensitivity of 87.5 % and specificity of 75 %. A thyroid lesion that shows RI greater than 12.5 % could be expected to be malignant (sensitivity 88.9 %, specificity 66.3 %). All malignant lesions showed an increase in SUVmax on the delayed images compared with the initial images. But in the group of benign lesions, 37.5 % (6/16) showed a decrease or no change in SUVmax. Dual-time-point F-FDG PET/CT, obtaining additional images 2 h after injection, seems to be a complementary method for the differentiation between malignancy and benignity of incidental thyroid lesions. [ABSTRACT FROM AUTHOR]

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Introduction: To determine the incidence of fluorine-18-fluorodeoxyglucose (FDG) avid thyroid incidentalomas detected on positron emission tomography (PET) with integrated computed tomography (CT), and correlate the FDG-PET-CT findings to cytology. Methods: A total of 942 FDG-PET-CT reports were retrospectively reviewed. Patients with FDG-avid thyroid incidentalomas were further reviewed for correlative cytology. Results: The incidence of FDG-avid thyroid incidentalomas is 2.2%. Thyroid malignancies were identified in 3 of 6 patients who underwent cytologic correlation, with a positive predictive value of 50% (95% confidence interval, 14%-86%). The mean maximum standardized uptake values of benign and malignant FDG-avid thyroid incidentalomas were 5.6 and 6.6, respectively. Conclusion: A FDG-avid thyroid incidentaloma may predict underlying malignancy. Cytologic assessment should be considered for FDG-avid thyroid incidentalomas. [ABSTRACT FROM AUTHOR]

Thyroid incidentaloma is defined as an unsuspected, asymptomatic thyroid lesion that is discovered on an imaging study or during an operation unrelated to the thyroid gland. Thyroid incidentalomas are most commonly detected on ultrasound, followed in frequency by computed tomography (CT) and magnetic resonance imaging (MRI), carotid duplex scanning and 2-18[F] fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET). The incidence of carcinoma in incidentally discovered thyroid disease is not insignificant. There are significant shortcomings of CT, MRI and PET imaging of the thyroid gland. As result, a thorough sonographic evaluation of the thyroid gland should be performed in all patients with a thyroid incidentaloma, regardless of the radiographic features identified on the “non thyroid “imaging modality. A sonographically confirmed thyroid nodule should be managed in an identical fashion to a clinically apparent thyroid nodule. [ABSTRACT FROM AUTHOR]

Despite the rising incidence of thyroid incidentalomas, their clinical significance remains unclear. The present study aimed to determine whether fluorodeoxyglucose positron emission tomography (FDG-PET) is associated with a significantly higher risk of clinically-significant thyroid carcinoma (CSC) in incidentalomas than other non-functional imaging modalities. Over a 2-year period, 89 patients were identified as having a thyroid incidentaloma. All patients had either surgery or fine needle aspiration cytology (FNAC) with a 12-month follow up to confirm the nature of the incidentaloma. Surgery was carried out for nodules with malignant or indeterminate FNAC result, or those with in a retrosternal location, with size > 4 cm or local symptoms. A total of 21 (23.6%) patients had their incidentaloma detected by FDG-PET (PET group) and 68 (76.4%) by non-PET imaging modalities (non-PET group). Differentiated thyroid carcinoma was confirmed in 18 (20.2%) patients. The rate of malignancy was 61.9% in the PET group and 7.4% in the non-PET group ( P = 0.001). After excluding the occult microcarcinomas, the risk of malignancy reduced to 14.6%, but the difference in malignancy rate became more marked between the PET and non-PET group (42.9% vs 2.9%, P = 0.001). The maximum standardized uptake value on FDG-PET was similar between benign and malignant lesions ( P = 0.124). The overall risk of CSC in thyroid incidentalomas was 14.6%. Those detected by FDG-PET were significantly more likely to harbour CSC than those by non-functional modalities. Incidentalomas with focal FDG uptake should be thoroughly investigated with USG and FNAC. [ABSTRACT FROM AUTHOR]

18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has established itself as an important imaging modality in many oncological and nononcological specialties and, as a consequence, it is increasingly being used in clinical practice. Since the first report of FDG being taken up by metastatic differentiated thyroid carcinoma (DTC) cells >20 years ago, various groups of investigators have explored the potential role of FDG-PET scanning in patients with benign and malignant thyroid neoplasms. With the increasing demand for FDG-PET scanning, clinicians are faced with the challenge of managing an increasing number of FDGPET- detected thyroid incidentalomas because their significance remains unclear. The aims of this review are to address some of these issues, specifically, the clinical significance of FDG-PET-detected thyroid incidentalomas, the ability of FDG-PET to characterize thyroid nodules, especially those with indeterminate fine needle aspiration cytology results, and the role of FDG-PET in patients with confirmed primary DTC and with suspected recurrent DTC, by reviewing the current literature. [ABSTRACT FROM AUTHOR]

Background: Focal thyroid incidentaloma by F-18 2-deoxy-2-F18-fluoro- d-glucose (FDG) positron emission tomography (PET) has been reported 1-4% of cancer patients and normal healthy population, with a risk of cancer ranging 14-50%. The aim of this study was to investigate the prevalence of thyroid incidentaloma in F-18 FDG PET/CT and risk of cancer, usefulness of visual and SUV and SUV differentiating malignant nodules and to define the predictable variables. Patients and methods: A total 159 patients with focal thyroid FDG incidentaloma during cancer evaluation with non-thyroid cancer were enrolled. After F-18 PET/CT, we analyzed the image visually and obtained semiquantitative indices. Result: The incidence of focal FDG thyroid incidentaloma is 1.36% and cancer risk is 23.3%. The incidence of focal thyroid FDG uptake was significantly higher in women (2.88 vs. 0.31%; χ = 136.4, p < 0.0001). Malignant thyroid incidentalomas show statistically significant higher value of SUV (malignant: median 4.53, range 2.1-12.0; benign: median 3.08, range 1.6-35, p = 0.0093). However, SUV have no statistical differences (malignant: median 2.17, range 1.77-3.19; benign: median 2.05, range 1.15-5.77, p = 0.0541). In ROC analyses, the optimal visual grades were >grade 3, and the optimal semiquantitative indices were 4.46 for SUV, 2.03 for SUV. The visual grade was superior to other variables for the differentiation malignant from benign thyroid incidentalomas. The size and visual grade was the potent predictor by logistic regression analysis. Conclusion: Focal thyroid FDG incidentalomas in non-thyroid cancer patients during evaluation have a high risk of malignancy. The size and visual grade are potential predictors for malignant thyroid incidentaloma. [ABSTRACT FROM AUTHOR]

Abstract: Background: The clinical significance of thyroid incidentalomas is controversial. Methods: The rate of malignancy was determined for patients with an incidentally discovered thyroid nodule, and results were stratified according to imaging modality as well as presence and type of pre-existing malignancy. Results: One hundred fifty patients were identified, of which 88 with a known malignancy were screened for metastases. Twenty-three (15%) patients were diagnosed with thyroid malignancy. Incidental nodules identified on positron emission tomography scan were malignant in 33% of the patients compared with 11% for those identified on computed axial tomography (P = .016). The rate of thyroid malignancy in patients with pre-existing nonthyroid malignancy (18%) was not significantly different from patients without a history of malignancy (13%, P = .36). Comments: Thyroid incidentalomas are associated with a high rate of malignancy. The rate of malignancy is highest for nodules discovered on positron emission tomography scan and is no different in patients with or without pre-existing malignancy. [Copyright &y& Elsevier]

Background: We performed a systematic review of the literature to provide an overview of the application of PET-based radiomics of [18F]FDG-avid thyroid incidentalomas and to discuss the additional value of PET volumetric parameters and radiomic features over clinical data. Methods: The most relevant databases were explored using an algorithm constructed based on a combination of terms related to our subject and English-language articles published until October 2021 were considered. Among the 247 identified articles, 19 studies were screened for eligibility and 11 met the criteria, with 4 studies including radiomics analyses. Results: We summarized the available literature based on a study of PET volumetric parameters and radiomics. Ten articles provided accurate details about volumetric parameters and their prospective value in tumour assessment. We included the data provided by these articles in a sub-analysis, but could not obtain statistically relevant results. Four publications analyzed the diagnostic potential of radiomics and the possibility of creating precise predictive models, their corresponding quality score being assessed. Conclusions: The use of PET volumetric parameters and radiomics analysis in patients with [18F]FDG-avid thyroid incidentalomas outlines a great prospect in diagnosis and stratification of patients with malignant nodules and may represent a way of limiting the need for unnecessary invasive procedures; however, further studies need to be performed for a standardization of the method. [ABSTRACT FROM AUTHOR]