Thyroid incidentaloma

Thyroid Nodules Detected on CT: A Retrospective Audit Study and Analysis of Differences in Reporting Practices Across Radiology Subspecialties

Thyroid nodules (TNs) are common incidental findings  on imaging and TN reporting practices are variable among radiologists, leading to unnecessary or inadequate investigations. We aimed to document current literature adherence for TN reporting practices on thoracic CTs and assess the variability in TN reporting across radiology subspecialties. This is a 2-parts retrospective study. First part was an audit study including all adult patients with thoracic CTs in January 2020. Patients with prior thyroidectomy and/or lack of TN were excluded. A local committee was created for literature review and elaboration of a local TN management algorithm. The algorithm was shared with the thoracic radiology team. Imaging and medical records were reviewed and adequate adherence was assessed in the pre- and post-intervention cohorts. Second part included all adult patients who underwent neck or cervical spine CT imaging in the same timeframe and with same inclusion/exclusion criteria as the pre-intervention thoracic cohort. In the pre-intervention cohort 802 participants were screened and 137 patients included. TNs were reported in "body" and "conclusion" of the report in 51% and 7% of the time respectively. Thyroid US was recommended in 10% of the patients and inadequately recommended 3% of the time. Overall adequate adherence was 86%. In the post-intervention cohort 962 participants were screened and 167 patients included. Thyroid US was recommended in 7% of the patients and no inadequate US recommendation was made. Overall adequate adherence in the post-intervention cohort was 93%, increased by 7% (P= 0.039). The musculoskeletal and neuroradiology cohorts reported more TNs in "conclusion" (P= 0.013 and P< 0.0001) and recommended more thyroid US (P = 0.033 and P= 0.0018) compared to the preintervention thoracic cohort. No significant difference in overall adequate adherence between subspecialties (P= 0.48 and P= 0.51). Improvement in adequate TN reporting on thoracic CT by 7% while reducing inadequate thyroid US recommendations from 3% to none. Significant reporting trends were also noted across radiology subspecialties.

Fine-Needle Aspiration Biopsy Evaluation-Oriented Thyroid Carcinoma Auxiliary Diagnosis

OBJECTIVE

Thyroid carcinoma is one of the most common diseases with an increasing incidence worldwide in recent years. In clinical diagnosis, medical practitioners normally take a preliminary thyroid nodule grading so that highly suspected thyroid nodules can be taken into the fine-needle aspiration (FNA) biopsy to evaluate the malignancy. However, subjective misinterpretations might lead to ambiguous risk stratification of thyroid nodules and unnecessary FNA biopsy.

METHODS

We propose a thyroid carcinoma auxiliary diagnosis method for fine-needle aspiration biopsy evaluation. Through integration of several deep learning models into a multibranch network for thyroid nodule risk stratification in the Thyroid Imaging Reporting and Data System (TIRADS) with pathological features and cascading of a discriminator, our proposed method provides an intelligent auxiliary diagnosis to assist medical practitioners in determining the necessity for further FNA.

DISCUSSION

Experimental results revealed that not only was the rate at which nodules are falsely diagnosed as malignant nodules effectively reduced, which avoids the unnecessary high cost and pain of aspiration biopsy, but also previously missing detected cases were identified with high possibility. By comparing the physicians' diagnosis alone with machine-assisted diagnosis, physicians' diagnostic performance improved with the aid of our proposed method, illustrating that our model can be very helpful in clinical practice.

CONCLUSION

Our proposed method might help medical practitioners avoid subjective interpretations and inter-observer variability. For patients, reliable diagnosis is provided and unnecessary painful diagnostics can be avoided. In other superficial organs such as metastatic lymph nodes and salivary gland tumors, the proposed method might also provide a reliable auxiliary diagnosis for risk stratification.

The influence of incidental detection of thyroid nodule on thyroid cancer risk and prognosis-A systematic review

BACKGROUND

Clinically inapparent thyroid nodules discovered serendipitously on imaging for nonthyroid indications are termed as thyroid incidentalomas. It is unclear whether these incidentalomas have a lower prevalence of malignancy or slower tumour progression compared to symptomatic nodules. The aims of this systematic review were to determine the impact of incidental detection of thyroid nodules on both the risk of malignancy and on prognosis in patients with thyroid cancer.

METHOD

PubMed and MEDLINE® on Web of Science databases were searched from inception to March 2020 for English language articles reporting on human studies of thyroid cancer risk and/or prognosis in incidental and nonincidental nodules.

RESULTS

Eighteen observational studies published between 1998 and 2020 were eligible for analysis; four studies reported on risk, nine on prognosis and five studies reported on both risk and prognosis. When comparing the incidental and nonincidental groups in the risk study, the odds of incidental detection in the cancer and benign groups ranged from 0.16 to 0.5 and 0.06 to 0.38, respectively (odds ratio [OR] = 0.64-2.86) in case-control studies (n = 6); the risk of malignancy for thyroid nodules ranged from 4% to 23.5% in the incidental and 3.8% to 28.7% in the nonincidental groups (relative risk = 0.13-6.27) in the cohort studies (n = 3). A meta-analysis of the eligible case-control studies (n = 3) showed a nonsignificant summated OR of 1.04 (95% confidence interval = 0.63-1.70; p = .88). In the prognosis study, five direct and thirteen indirect markers of prognosis were compared between the incidental and nonincidental groups. A meta-analysis was not possible but incidentally detected thyroid cancer had better progression-free and overall survival.

CONCLUSION

Current evidence suggests that investigation and management of thyroid nodules should not be influenced by the mode of detection.

Aberrant intrathyroidal lymph node metastasis in classical papillary thyroid carcinoma

Background

In cases of papillary thyroid carcinoma (PTC), lymph nodes are a typical site of metastasis. Extrathyroidal tissue involvement in differentiated thyroid carcinoma causes the disease to progress and affects the patients’ treatment options. Papillary thyroid carcinoma (PTC) is the common type in differentiated thyroid carcinoma (DTC), the other type is follicular thyroid carcinoma (FTC). Ectopic sites, such as intrathyroidal lymph node invasion in classical papillary thyroid malignancy, are extremely uncommon. It can be difficult to detect an intrathyroidal lymph node (ITLN) during a histopathological test, but it is important to do so since it affects the stage of the disease and subsequent treatment.

Case presentation

We present the case of a 63-year-old woman who presented with multinodular goitre and underwent total thyroidectomy. She was diagnosed with aberrant intrathyroidal lymph node metastases during pathological testing, resulting in an upgrade in treatment. Owing to the exceptionally unusual ectopic position of lymph node metastasis, in this case, there is a risk of diagnostic and therapeutic misinterpretation. This patient was treated with high-dose radioactive iodine in view of lymph node metastases.

Conclusions

Identification of ITLN by imaging characteristics is sometimes difficult, being often an intraoperative discovery and histopathological correlation that lead to upstage the disease and alter the final management.

What to Do with Incidentally Discovered Pituitary Abnormalities?

Pituitary incidentalomas are discovered in approximately 10% to 40% of brain images. A complete patient history, physical examination, and dedicated pituitary function testing are needed, and subsequent results should lead to appropriate patient management. However, most lesions are asymptomatic pituitary adenomas or Rathke cleft cysts with a benign course. Many lesions can be clinically significant, including prolactinomas or other pituitary adenomas that warrant specific pituitary disease treatment. In other cases, mass effect causing visual compromise or refractory headache indicates a need for surgery. Here, various facets of a complex evaluation and treatment algorithm for pituitary incidentalomas are reviewed.

The dilemma of 18F-FDG PET/CT thyroid incidentaloma: what we should expect from FNA. A systematic review and meta-analysis

PURPOSE

¹⁸F-FDG thyroid incidentaloma (TI) occurs in ~2% of PET/CT examinations with a cancer prevalence of up to 35-40%. Guidelines recommend fine-needle aspiration cytology (FNA) if a focal ¹⁸F-FDG TI corresponds to a sonographic nodule >1 cm. The aim of this systematic review and meta-analysis was to provide evidence-based data on the diagnostic distribution of ¹⁸F-FDG TIs in the six Bethesda systems for reporting thyroid cytopathology (BETHESDA) subcategories.

METHODS

Original studies reporting ¹⁸F-FDG TIs and cytologically classified according to BETHESDA were included. Six separate meta-analyses were performed to obtain the pooled prevalence (95% confidence interval, 95% CI) of ¹⁸F-FDG TIs in the six BETHESDA subcategories.

RESULTS

Fifteen studies were finally included. Nine studies were from Asian/Eastern and six from Western countries. FNA data according to BETHESDA was available in 2304 cases. The pooled prevalence of ¹⁸F-FDG TIs according to BETHESDA was BETHESDA I 10% (6-14), BETHESDA II 45% (37-53), BETHESDA III 8% (3-13), BETHESDA IV 8% (5-12), BETHESDA V 6% (4-9), BETHESDA VI 19% (13-25). A significantly different prevalence was found in the BETHESDA IV between Asian/Eastern (2%) and Western (19%) studies.

CONCLUSION

Two-thirds of focal ¹⁸F-FDG TIs undergoing FNA have either malignant (BETHESDA VI) or benign (BETHESDA II) cytology while a minority will have indeterminate (BETHESDA III or IV) FNA results. Significant differences between Asian/Eastern and Western studies are also present in the prevalence of indeterminate FNA results.

FNA indication according to ACR-TIRADS, EU-TIRADS and K-TIRADS in thyroid incidentalomas at 18F-FDG PET/CT

OBJECTIVE

Focal thyroid incidentaloma (TI) occurs in a 2% of ¹⁸F-FDG PET/CT and about one-third of TIs is cancer. Due to the lack of evidence on the optimal management of TI, current guidelines suggest performing fine-needle aspiration cytology (FNA). The study aim was to evaluate the reliability of ACR-TIRADS, EU-TIRADS, and K-TIRADS in indicating FNA in TIs.

DESIGN

We retrospectively reviewed ¹⁸F-FDG PET/CT TIs recorded during the period 2016-2019. Enrolled were TIs with histologic outcome and autonomous nodules. Cases with uncertain matching between ¹⁸F-FDG PET/CT, US/scintiscan and histology were excluded.

RESULTS

Eighty TIs at ¹⁸F-FDG PET/CT (median size 17 mm, median SUVmax 7.85) were included; a 26.2% was cancer. The percentage of nodules classified as high risk according to ACR-TIRADS, EU-TIRADS, and K-TIRADS was 20%, 30%, and 29.8%, respectively. The cancer prevalence in high-risk class was 56.2%, 66.7%, and 65.2% in ACR-TIRADS, EU-TIRADS, and K-TIRADS, respectively. ACR-TIRADS had the lowest number of cases with FNA indication (48%) and the K-TIRADS, the highest one (75%). Evaluating the reliability of the three systems in indicating FNA, we found a 100% sensitivity and NPV for EU-TIRADS and K-TIRADS; while all the three systems showed poor specificity and PPV.

CONCLUSION

All TIRADSs were reliable to stratify the risk of cancer in focal TI. Comparing their reliability in indicating FNA, we found a good performance of EU-TIRADS and K-TIRADS. Considering the high cancer percentage expected in this setting of patients, those TIRADS with higher propensity to indicate FNA should be preferred.

Development and Internal Validation of a Predictive Model for Individual Cancer Risk Assessment for Thyroid Nodules

OBJECTIVE

The objective of this study was to develop and validate a predictive model for the assessment of the individual risk of malignancy of thyroid nodules based on clinical, ultrasound, and analytic variables.

METHODS

A retrospective case-control study was carried out with 542 patients whose thyroid nodules were analyzed at our endocrinology department between 2013 and 2018 while undergoing treatment for thyroidectomy. Starting with a multivariate logistic regression analysis, which included clinical, analytic, and ultrasound variables, a predictive model for thyroid cancer (TC) risk was devised. This was then subjected to a cross-validation process, using resampling techniques.

RESULTS

In the final model, the independent predictors of the risk of malignancy were: being male, age of the extremes, family history of TC, thyroid-stimulating hormone level >4.7 μU/L, presence of autoimmune thyroiditis, solid consistency, hypoechogenicity, irregular or microlobed borders, nodules that are taller than they are wide, microcalcifications, and suspicious adenopathy. With a cut-off point of 50% probability of thyroid cancer, the predictive model had an area under the receiver operating characteristic curve of 0.925 (95% confidence interval 0.898 to 0.952). Finally, using the 10-fold cross-validation method, the accuracy of the model was found to be 88.46%, with a kappa correlation coefficient of 0.62.

CONCLUSION

A predictive model for the individual risk of malignancy of thyroid nodules was developed and validated using clinical, analytic, and ultrasound variables. An online calculator was developed from this model to be used by clinicians to improve decision-making in patients with thyroid nodules.

Evidence-Based Data About Prevalence and Risk of Malignancy of Thyroid Incidentalomas Detected by Different PET Radiopharmaceuticals

Background:

To date, several meta-analyses and systematic reviews have reported data about the prevalence and risk of malignancy of thyroid incidentalomas detected by different PET radiopharmaceuticals.

Objective:

This article aims to summarize the published evidence-based data about the prevalence and risk of malignancy of thyroid incidentalomas detected by different PET radiopharmaceuticals.

Methods:

A comprehensive computer literature search of systematic reviews and meta-analyses published up to July 2019 in PubMed/MEDLINE and Cochrane library databases regarding the prevalence and risk of malignancy of thyroid incidentalomas detected by different PET radiopharmaceuticals was carried out.

Results:

We have summarized the data about prevalence and risk of malignancy of thyroid incidentalomas detected by different PET radiopharmaceuticals (fluorine-18 fluorodeoxyglucose, radiolabelled choline and prostate-specific membrane antigen) taking into account 8 evidence-based articles.

Conclusion:

Evidence-based data demonstrated that thyroid incidentalomas detected by different PET radiopharmaceuticals are not infrequent and their risk of malignancy is not negligible, in particular if focal pattern is evident at PET, thus requiring further clinical and instrumental evaluation.

Correlation of vascular endothelial growth factor and vascular endothelial growth factor receptor-1 levels in serum and thyroid nodules with histopathological and radiological variables

BACKGROUND/AIM:

Vascular endothelial growth factor (VEGF) is a major cytokine in angiogenesis and has a role on aggressivity of various tumors. The expression of VEGF has been shown to increase in differential thyroid cancer. The aim of the study was to evaluate serum and intranodular VEGF (nVEGF) and VEGF receptor-1 (VEGFR-1) levels in patients with thyroid nodules and their relevance to ultrasonographic and pathological results.

MATERIALS AND METHODS:

A total of eighty patients were included in the study. Thyroid fine-needle aspiration biopsies were performed, and the levels of serum and nVEGF and VEGFR-1 were measured. Any possible correlations between serum and nVEGF, VEGFR-1, and biochemical/radiological variables were investigated.

RESULTS:

There were no significant differences between serum VEGF (sVEGF), nVEGF, sVEGFR-1, nVEGFR-1 levels, number of nodules, size of nodules, and benign and malignant ultrasonographic features. sVEGF and nVEGF were higher in malignant or suspicious nodules than that in benign nodules, but did not reach statistical significance (P > 0.05). sVEGFR-1 and nVEGFR-1 levels were higher in hyperthyroid patients than that in euthyroid patients (P < 0.05 and P = 0.003, respectively). nVEGFR-1 level was higher in hypothyroid patients than that in euthyroid patients (P = 0.016). sVEGF level was found to be higher in hyperactive nodules than that in others. Both sVEGFR-1 (P = 0.008) and nVEGF levels (P = 0.01) significantly increased with increasing age. nVEGFR-1 decreased with increasing body mass index (BMI) (P = 0.004).

CONCLUSIONS:

Our study showed the relationships of sVEGF, nVEGF, sVEGFR-1, and nVEGFR-1 levels with age, gender, BMI, and hyperthyroidism. To determine the role of VEGF/VEGFR-1 in thyroid nodules, further studies are required with a large number of patients.

Diagnostic Value of Machine Learning-Based Quantitative Texture Analysis in Differentiating Benign and Malignant Thyroid Nodules

Aim

The aim of this study is to evaluate the diagnostic value of machine learning- (ML-) based quantitative texture analysis in the differentiation of benign and malignant thyroid nodules.

Materials and methods

A sum of 306 quantitative textural features of 235 thyroid nodules (102 malignant, 43.4%; 133 benign, 56.4%) of a total of 198 patients were investigated using the random forest ML classifier. Feature selection and dimension reduction were conducted using reproducibility testing and a wrapper method. The diagnostic accuracy, sensitivity, specificity, and area under curve (AUC) of the proposed method were compared with the histopathological or cytopathological findings as reference methods.

Results

Of the 306 initial texture features, 284 (92.2%) showed good reproducibility (intraclass correlation ≥0.80). The random forest classifier accurately identified 87 out of 102 malignant thyroid nodules and 117 out of 133 benign thyroid nodules, which is a diagnostic sensitivity of 85.2%, specificity of 87.9%, and accuracy of 86.8%. The AUC of the model was 0.92.

Conclusions

Quantitative textural analysis of thyroid nodules using ML classification can accurately discriminate benign and malignant thyroid nodules. Our findings should be validated by multicenter prospective studies using completely independent external data.

18F-choline PET/CT incidental thyroid uptake in patients studied for prostate cancer

PURPOSE

Thyroid incidental uptake is defined as a thyroid uptake incidentally detected by imaging examinations performed for non-thyroid disease. The aim of this study was to establish the prevalence and the pathological nature of focal thyroid incidental uptake (FTIU) among patients studied with 18F-choline-PET/CT.

MATERIALS AND METHODS

We retrospectively evaluated 368 patients who performed 18F-choline-PET/CT between June 2016 and August 2018. The PET images were analyzed visually and semi-quantitatively by measuring the maximum standardized uptake value (SUVmax) and the mean SUV (SUVmean) of the thyroid gland and of the FTIU; every focal thyroid uptake deviating from physiological distribution and background was considered FTIU. Final diagnosis of FTIU was obtained by cytological or histological examination after surgery.

RESULTS

The average SUVmax and SUVmean of thyroid gland in population were 3 and 1.8. Among 368 patients, FTIU was identified in nine cases (2.4%) and eight underwent further investigations to determine the nature. Two FTIU were classified as malignant (thyroid carcinoma), whereas five were benign (three nodular hyperplasia, one follicular adenoma, one Hurtle cell adenoma) and one indeterminate at cytological examination. In malignant lesions, average SUVmax was 9.6 and 4.5, respectively, while average SUVmean was 5.3 and 2.9, respectively. Average SUVmax and SUVmean of benign lesions were 4.9 and 3.2 and of the indeterminate lesion 5 and 3, respectively.

CONCLUSIONS

18F-choline-PET/CT FTIU may be a relevant diagnostic reality, which requires further investigations and affects management, especially considering that, despite being mainly benign, also malignancy is possible.

Thyroid incidentaloma as a "PAIN" phenomenon- does it always require surgery?

A thyroid nodule discovered during imaging study performed due to unrelated thyroid disease is known as a thyroid incidentaloma, while positron emission tomography (PET) associated incidental neoplasm of thyroid is known as a "PAIN" phenomenon.To evaluate which patients with "PAIN" phenomenon should undergo surgery in regards to cytology results.Retrospective review of 4716 patients consecutively admitted and surgically treated in tertiary surgical center. 49 (1.04%) patients with "PAIN" phenomenon were identified. All of them had ultrasound-guided fine needle aspiration biopsy (UG-FNAB) performed and cytological results were evaluated according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). Patients were divided into 2 subgroups according to histopathological diagnosis: group 1 (n = 25) with benign tumor and group 2 (n = 24) with thyroid cancer.Cytology results were the significant predictors of cancer occurrence in patients with "PAIN" phenomenon (P < .0001). Logistic regression analysis confirmed that category III or higher of TBSRTC in patients with "PAIN" phenomenon significantly increased the risk of cancer (OR = 168.7, P < .0001).Patients with "PAIN" phenomenon and cytology assigned to category III or higher of the Bethesda system should undergo surgery due to significant risk of thyroid malignancy.

Fine-needle aspiration in all thyroid incidentalomas at 18 F-FDG PET/CT: Can EU-TIRADS revise the dogma?

OBJECTIVE

Focal thyroid incidentalomas (TIs) are observed in 2% of ¹⁸ F-FDG PET/CT representing malignancy in one-third of cases. Currently, due to the lack of evidence on their optimal management, guidelines suggest fine-needle aspiration cytology (FNAC). The study aim was to evaluate the role of ultrasound evaluation according to EU-TIRADS to assess the risk of TIs and inform FNAC prescriptions.

DESIGN

We retrospectively reviewed ¹⁸ F-FDG PET/CT TIs recorded during the period 2014-2017. Enrolled were TIs with histological outcome and autonomous nodules. Cases with uncertain matching between ¹⁸ F-FDG PET/CT, ultrasound and histology were excluded.

RESULTS

According to the selection criteria, 75 TIs, being 13 (17.3%) malignant and 62 (82.7%) benign, were included. Cancers had significantly higher SUVmax and SUVmax ratio (Mann-Whitney P < 0.01) than benign, and the most accurate cut-offs were >7.1 and >3.65, respectively. At ultrasound, the cancer rate was 0% in EU-TIRADS 2, 2.9% in EU-TIRADS 3, 4.2% in EU-TIRADS 4% and 78.6% in EU-TIRADS 5 (chi-squared P < 0.001). Sensitivity, specificity, PPV, NPV and accuracy for malignancy were 92%, 64%, 35%, 98% and 69% for SUVmax; 85%, 68%, 36%, 96% and 71% for SUVmax ratio; and 85%, 95%, 79%, 97% and 93% for EU-TIRADS, respectively. The absence of all these three features reached a specificity of 97.1%.

CONCLUSIONS

EU-TIRADS, within a clinical careful approach, can discriminate with significant accuracy lesions at high risk of malignancy from those at low risk among TIs at ¹⁸ F-FDG PET/CT. Additionally, a centre-based threshold for SUV parameters should be useful for the initial assessment of these lesions during PET/CT reading and reporting.

Evaluation and management of thyroid incidentalomas detected prior to the parathyroid surgery

BACKGROUND

We investigated the management of thyroid incidentalomas associated with cases of parathyroid lesions in order to suggest a practical approach to their management from a surgical point of view.

METHODS

639 patients underwent radiological and ultrasound investigation of the thyroid area because of parathyroid disorders and parathyroidectomy and had at least three years of follow-up. All follow-up data for these cases were investigated from the moment the lesion was detected and up to the last report.

RESULTS

Out of 639 cases, incidental or asymptomatic thyroid nodules were found in 179 patients (28%), of which, 22 patients were operated (parathyroidectomy + thyroidectomy) and 157 remained with the nodules. For these patients, the average period of follow-up was 7 years 5 mo. Following the results of the follow-up, 52 patients (33%) were suggested to have surgery of the thyroid gland and 49 were operated (16 total thyroidectomies and 33 hemithyroidectomies). The complications after the second surgery included recurrent laryngeal nerve palsy (n = 3), superior laryngeal nerve palsy (n = 1), permanent hypocalcaemia (n = 8), and surgical damage to the internal jugular vein (n = 1). All complications occurred at the previously operated side of the neck.

CONCLUSION

While surgery remains the management of choice for malignant thyroid incidentalomas, for benign cases, if an asymptomatic thyroid nodule was detected inside the thyroid lobe on the side of planned parathyroidectomy and if the size of the nodule is ˃1.5 cm we suggest combined parathyroidectomy + hemithyroidectomy.

Ultrasound requested by general practitioners or for symptoms unrelated to the thyroid gland may explain higher prevalence of thyroid nodules in females

BACKGROUND

A higher prevalence of thyroid nodules/carcinoma in females is well-known from the literature. The reasons for this difference are not fully explained. We intended to assess gender variation in the referral for ultrasound-guided fine needle aspiration (FNA) of thyroid nodules, to study reasons for gender referral differences, and to assess differences in nodules characteristics between genders.

METHODS

Included were 272 consecutive patients, with 290 nodules submitted to FNA. Patients were questioned on the reason why ultrasound (US) examination was required. Electronic medical records were reviewed. Nodules' ultrasound/cytological characteristics were assessed. Variables studied: referral cause; referral pattern (hospital-specialist versus general-practitioner); number of nodules; age, thyroid function; nodule size, TIRADS classification, resistive index, Doppler pattern, Bethesda categorisation. Variables were compared between males and females referred for FNA. Significant variables were assessed with logistic regression.

RESULTS

Of the 272 patients, 215(79%) were women with a female:male referral ratio for FNA of 3.8:1. Non-parametric statistically significant differences (p < 0.05) were found between genders in: thyroid function, nodule size, referral pattern and referral cause. Nodule size and thyroid function tests became non-significant in logistic regression. Cause and referral pattern remained significantly associated with gender. Referral by a general-practitioner was associated with a 2.6-fold increase in odds of referring a female. Causes unrelated to the thyroid were associated with a 3.2-fold increase in odds of female reference.

CONCLUSIONS

A referral bias might be responsible for the higher rate of thyroid nodules in female patients, both due to referral by general practitioners and due to causes indirectly related to the thyroid gland.

Focal thyroid incidental uptake detected by 18F-fluorodeoxyglucose positron emission tomography

Aim: To perform a meta-analysis of published data on the prevalence and risk of malignancy of focal thyroid incidental uptake (FTIs) detected by Fluorine-18-Fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) or PET/CT. Methods: A comprehensive literature search of studies published up to and including December 2012 was performed. Pooled prevalence and malignancy risk of FTIs were calculated, including a sub-analysis for the geographic areas of origin of the studies. Results: 34 studies including 215 057 patients were selected. Pooled prevalence of FTIs was 1.92% (95% confidence interval [95%CI]: 1.87–1.99%). Overall, 1522 FTIs underwent histopathology evaluation. Pooled risk of malignancy was 36.2% (95%CI: 33.8–38.6%), without significant differences among various geographic areas. Conclusions: FTIs are observed in about 2% of 18F-FDG-PET or PET/CT scans and carry a significant risk of malignancy. Therefore, further investigation is warranted whenever FTIs are detected by 18F-FDG-PET or PET/CT.

Evaluation of Incidental Thyroid Nodules in Cancer Patients

OBJECTIVE

Frequency of thyroid cancer in incidental thyroid nodules identified by imaging techniques in cancer patients is higher than that in the normal population. In the retrospective study, we have both investigated the incidence of thyroid cancer in incidentally identified nodules and compared the imaging techniques to determine whether there is any difference between them in detection of malign nodules.

METHODS

A total of 7319 patients who underwent thyroid fine-needle aspiration biopsy (FNAB) were included in the study. The data of 174 patients who had previously been diagnosed with a hematologic or solid malignancy prior to the FNAB procedure and had incidentally identified thyroid nodules were evaluated retrospectively.

RESULTS

Eighty-six (49.5%) of the incidental nodules were identified with ultrasonography (USG), 62 (35.6%) with positron emission tomography (PET) or PET/computed tomography (PET/CT), and 26 (14.9%) with CT. As a result of thyroidectomy, papillary carcinoma was identified in 8 (4.6%) patients, and metastasis to the thyroid of a primary cancer was found in 3 (1.7%) patients. While the papillary carcinoma proportion in the nodules identified by USG was 3.4%, PET/CT was 8.9%. A cut-off maximal standardized uptake value of 11.6 in PET/CT indicated malignancy achieving a sensitivity of 83.3% and a specificity of 91.1%.

CONCLUSION

Whether the nodule in the incidental thyroid nodules of cancer patients is identified using USG or PET/CT, the risk of thyroid cancer is similar. However, cancer risk is higher in the event of a higher focal uptake in the nodules identified by PET/CT.

Risk of Malignancy in Thyroid Incidentaloma is Not Increased in Overweight or Obese Patients, but in Young Patients

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. We aim to evaluate the relationship between overweight or obese and risk of malignancy in patients with thyroid incidentaloma detected by F18-flurodeoxyglucose positron emission tomography/computed tomography and factors to predict risk of malignancy in thyroid incidentaloma. From January 2010 to December 2013, a total of 238 patients were eligible for this study. Using the Bethesda system for reporting thyroid cytopathology, categories I-III were defined as a nonmalignancy and categories V-VI were defined as a malignancy. When patients with body mass index (BMI) of less than 23 and 23 or more were divided into two groups of normal and overweight or obese, risk of malignancy of thyroid incidentaloma was not significantly different between two groups (P = 0.1812). In logistic regression analysis, age was the only variable that showed a significant association with malignancy of thyroid incidentaloma (odds ratio 0.9608, P = 0.0021). However, none of sex, height, weight, and BMI was predictor of malignancy of thyroid incidentaloma. We demonstrated that being overweight or obese did not increase rate of malignancy in patients with thyroid incidentaloma.

Differences in the Recurrence and Survival of Patients with Symptomatic and Asymptomatic Papillary Thyroid Carcinoma: An Observational Study of 11,265 Person-Years of Follow-Up

BACKGROUND

Papillary thyroid carcinoma (PTC) generally has an indolent course and favorable prognosis. However, an optimal treatment strategy for asymptomatic PTC is not clear. We compared the recurrence and survival outcomes of patients with asymptomatic and symptomatic PTC and identified the associated risk factors.

MATERIALS AND METHODS

Patients with previously untreated PTC of size ≤2 cm and who underwent curative surgery were included in this analysis. Asymptomatic PTC was defined as a tumor detected only by ultrasonography, computed tomography (CT), magnetic resonance imaging, and/or ¹⁸F-fluorodeoxyglucose positron emission tomography/CT. Clinical factors, operative and pathologic findings, and posttreatment outcomes were compared between the aforementioned two groups. Univariate and multivariate analyses were performed to identify the factors associated with recurrence-free survival (RFS) and overall survival (OS).

RESULTS

Out of 1419 patients, 1259 patients (88.7%) were asymptomatic. Patients with symptomatic PTC had significantly larger tumor size, palpability, extrathyroidal extension, high tumor and node stages, and were more likely to undergo treatment with radioactive iodine therapy compared with patients with asymptomatic PTC (p < 0.05 each). Recurrence was significantly higher in the symptomatic PTC group than in the asymptomatic group (p < 0.001). Asymptomatic PTC was an independent predictor of RFS and OS and had higher five-year rates than those associated with symptomatic tumors: 97.3% and 90.6% for RFS (p < 0.001) and 99.4% and 96.9% for OS (p < 0.001), respectively.

CONCLUSION

Symptomatic PTC is associated with higher recurrence and lower overall survival rates than asymptomatic PTC. Symptomatic PTC may require total thyroidectomy and close posttreatment surveillance.

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

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

THYROID MALIGNANCY RISK OF INCIDENTAL THYROID NODULES IN PATIENTS WITH NON-THYROID CANCER

Context

Thyroid incidentaloma is a common disorder in endocrinology practice. Current literature regarding the risk of thyroid cancer in incidentalomas found in patients with non-thyroid cancer is limited.

Objective

The aim of the present study was to investigate the frequency of thyroid malignancy in thyroid incidentalomas detected in patients with non-thyroid cancer.

Design

Case control study.

Subjects and Methods

The database of 287 thyroid nodules from 161 patients with a history of non-thyroid cancer followed between 2008 and 2014 were retrospectively evaluated.

Results

From 287 thyroid nodules, 69.7 % had a benign final cytology. Thyroid cancer detected in one nodule while follicular neoplasia detected in 4 nodules, atypia of unknown significance (AUS) detected in 10 nodules, Hurthle cell neoplasia detected in 5 nodules and suspicious for malignancy detected in 6 nodules according to fine needle aspiration biopsy results. Metastasis of the non-thyroid cancer to the thyroid gland was detected in 4 nodules. Twenty seven nodules from 15 patients were removed with surgery. There were 3 malignant nodules found after surgery (1 papillary, 1 follicular and 1 medullary cancer). In addition to these three thyroid cancers, two patients with benign nodules had co-incidental thyroid cancer detected after surgery. Finally, 11.1 % of thyroid nodules which underwent thyroid surgery had malignant histopathology except for co-incidental and metastatic cancers.

Conclusions

The frequency of thyroid malignancy seems not to be substantially increased in incidental thyroid nodules detected in patients with non-thyroid cancer when these patients were evaluated in nodule-based approach.

Midkine: A Novel Biomarker to Predict Malignancy in Patients with Nodular Thyroid Disease

Background. Midkine (MK), a new heparin-binding growth factor, plays important roles in a variety of biological phenomena such as carcinogenesis, inflammation, and angiogenesis. In this study, we aimed to evaluate serum midkine (SMK) and nodular midkine (NMK) levels in patients with thyroid nodules to predict malignancy and whether there was any association between. Methods. A total of 105 patients (74 women, 31 men) with thyroid nodules were enrolled. The levels of SMK and NMK were measured. Any possible correlation between SMK, NMK, and biochemical, cytopathological, or radiological variables was investigated. Results. Both SMK and NMK were found to be higher in hypoechoic nodules with an irregular border and without a halo (p < 0.05). Serum MK levels were significantly higher in nodules with microcalcifications than nodules with macrocalcification or without calcification (p = 0.001). SMK levels were found to be correlated with NMK levels (SMK 0.63 ng/ml versus 1.04 ng/mL and NMK 0.55 ng/mL versus 0.55 ng/mL, r (2) = 0.54, p < 0.001). Conclusion. Both SMK and NMK can predict tumorigenesis of highly malignant/suspicious thyroid cytopathology and also well correlated with sonographic features of thyroid nodules. We suggest that MK levels may serve as an alternative biomarker, in conjunction with the cytopathological results in preoperative assessment of thyroid nodules.

The Management of Thyroid Nodules

Thyroid nodules are extremely common and are detected in 3%-7% of the general population by palpation and in 70% of the population by ultrasonography (USG). Approximately 5%-15% of these nodules are malignant. Therefore, in nodule examination, our primary aim is to detect malignant nodules. Besides the medical history and the findings of the physical examination, USG and fine-needle aspiration biopsy (FNAB) are the most commonly used methods to examine these nodules. Ultrasound-guided FNAB and on-site assessment of FNA specimens are suggested to decrease false negative and non-diagnostic test results. FNAB results in the "atypia of undetermined significance" group is challenging in the follow-up or treatment of the nodule. In this group, to differentiate the malignant nodules, other developing methods, such as analyzing molecular genetic markers, protein markers, and elastography, are generally studied. However, these methods are not used in a routine nodule examination because of cost-benefit analysis.

Benign and Malignant Thyroid Incidentalomas Are Rare in Routine Clinical Practice: A Review of 97,908 Imaging Studies

PURPOSE

Thyroid nodules incidentally identified on imaging are thought to contribute to the increasing incidence of thyroid cancer. We aim to determine the true rate of incidental thyroid nodule reporting, malignancy rates of these nodules, and to compare these findings with rates of detection by dedicated radiology review.

METHODS

A cross-sectional analysis was done to determine the prevalence of thyroid nodules in radiologist reports by analyzing all reports for CT, PET, and MRI scans of the head, neck, and chest as well as neck ultrasounds performed at a tertiary care center from 2007 to 2012. Retrospective chart review was performed on patients with a reported thyroid nodule to determine clinical outcomes of these nodules. Radiology reports were compared with dedicated radiology review of 500 randomly selected CT scans from the study group to determine the difference between clinical reporting and actual prevalence of thyroid nodules.

RESULTS

97,908 imaging studies met inclusion criteria, and 387 (0.4%) thyroid incidentalomas were identified on radiology report. One hundred and sixty three (42.1%) of these nodules were worked up with fine-needle aspiration, diagnosing 27 thyroid cancers (0.03% of all studies, 7.0% of reported incidentalomas). The prevalence of incidentalomas clinically reported was 142/100,000 CT scans, 638/100,000 MRIs, 358/100,000 PET scans, and 6,594/100,000 ultrasounds. In contrast, review of CT scans screening for thyroid nodules had a prevalence of 10%.

CONCLUSION

Routine clinical reporting of incidental thyroid nodules is far less common than on dedicated review.

IMPACT

These data contradict the notion that incidentalomas contribute significantly to rising thyroid cancer rates.

Thyroid ultrasound features and risk of carcinoma: a systematic review and meta-analysis of observational studies

BACKGROUND

Thyroid nodules are a common finding in the general population, and their detection is increasing with the widespread use of ultrasound (US). Thyroid cancer is found in 5-15% of cases depending on sex, age, and exposure to other risk factors. Some US parameters have been associated with increased risk of malignancy. However, no characteristic seems sufficiently reliable in isolation to diagnose malignancy. The objective of this meta-analysis was to evaluate the diagnostic performance of US features for thyroid malignancy in patients with unselected thyroid nodules and nodules with indeterminate fine-needle aspiration (FNA) cytology.

METHODS

Electronic databases were reviewed for studies published prior to July 2012 that evaluated US features of thyroid nodules and reported postoperative histopathologic diagnosis. A manual search of references of review and key articles, and previous meta-analyses was also performed. A separate meta-analysis was performed including only nodules with indeterminate cytology. Analyzed features were solid structure, hypoechogenicity, irregular margins, absence of halo, microcalcifications, central vascularization, solitary nodule, heterogeneity, taller than wide shape, and absence of elasticity.

RESULTS

Fifty-two observational studies (12,786 nodules) were included. Nine studies included nodules with indeterminate cytology as a separate category, comprising 1851 nodules. In unselected nodules, all US features were significantly associated with malignancy with an odds ratio varying from 1.78 to 35.7, and microcalcifications, irregular margins, and a taller than wide shape had high specificities (Sp; 87.8%, 83.1%, 96.6%) and positive likelihood ratios (LHR; 3.26, 2.99, 8.07). Absence of elasticity was the single feature with the best diagnostic performance (sensitivity 87.9%, Sp 86.2%, and positive LHR 6.39). The presence of central vascularization was the most specific US feature in nodules with indeterminate cytology (Sp 96% and positive LHR 2.13).

CONCLUSIONS

US features in isolation do not provide reliable information to select nodules that should have a FNA performed. A combination of US characteristics with higher likelihood ratios and consequently with higher post-test probabilities of malignancy-microcalcifications, or a taller than wide shape, or irregular margins, or absence of elasticity-will probably identify nodules with an increased risk for malignancy. Further studies are required to standardize elastography techniques and evaluate outcomes, especially in nodules with an indeterminate cytology.

Thyroid incidentalomas in patients with multiple endocrine neoplasia type 1

OBJECTIVE

Currently, little is known about the prevalence of thyroid tumors in multiple endocrine neoplasia type 1 (MEN1) patients and it is unclear whether tumorigenesis of these thyroid tumors is MEN1-related. The aim of the study was to assess the prevalence of thyroid incidentalomas in MEN1 patients compared with nonMEN1 patients and to verify whether thyroid tumorigenesis is MEN1-related.

DESIGN

A cross-sectional study.

METHODS

The study included two groups: patients with MEN1 and a matched non-MEN1 control group without known thyroid disease, who underwent an ultrasound of the neck for the localization of parathyroid adenoma. Ninety-five MEN1 patients underwent ultrasound of the neck and were matched on gender and age with non-MEN1 patients. The prevalence of thyroid incidentalomas described in the ultrasound report was scored. Multinodular goiters, solitary nodes, and cysts were scored as incidentalomas. Presence of nuclear menin expression was evaluated by menin immunostaining of the thyroid tumors.

RESULTS

In the MEN1 group, 43 (45%) patients had a thyroid incidentaloma compared with 48 (51%) in the non-MEN1 group, of which 14 (15%) and 16 (17%), respectively, were solitary nodes. Menin was expressed in the nuclei of all evaluated thyroid tumors.

CONCLUSIONS

MEN1 patients do not have a higher prevalence of thyroid incidentalomas compared with primary hyperparathyroidism patients without the diagnosis of MEN1. Menin was expressed in the thyroid tumors of MEN1 patients.

Thyroid lesions incidentally detected by (18)F-FDG PET-CT - a two centre retrospective study

Background.

Incidental ¹⁸F-FDG uptake in the thyroid on PET-CT examinations represents a diagnostic challenge. The maximal standardized uptake value (SUV_max) is one possible parameter that can help in distinguishing between benign and malignant thyroid PET lesions.

Patients and methods.

We retrospectively evaluated ¹⁸F-FDG PET-CT examinations of 5,911 patients performed at two different medical centres from 2010 to 2011. If pathologically increased activity was accidentally detected in the thyroid, the SUV_max of the thyroid lesion was calculated. Patients with incidental ¹⁸F-FDG uptake in the thyroid were instructed to visit a thyroidologist, who performed further investigation including fine needle aspiration cytology (FNAC) if needed. Lesions deemed suspicious after FNAC were referred for surgery.

Results.

Incidental ¹⁸F-FDG uptake in the thyroid was found in 3.89% — in 230 out of 5,911 patients investigated on PET-CT. Malignant thyroid lesions (represented with focal thyroid uptake) were detected in 10 of 66 patients (in 15.2%). In the first medical centre the SUV_max of 36 benign lesions was 5.6 ± 2.8 compared to 15.8 ± 9.2 of 5 malignant lesions (p < 0.001). In the second centre the SUV_max of 20 benign lesions was 3.7 ± 2.2 compared to 5.1 ± 2.3 of 5 malignant lesions (p = 0.217). All 29 further investigated diffuse thyroid lesions were benign.

Conclusions.

Incidental ¹⁸F-FDG uptake in the thyroid was found in 3.89% of patients who had a PET-CT examination. Only focal thyroid uptake represented a malignant lesion in our study — in 15.2% of all focal thyroid lesions. SUV_max should only serve as one of several parameters that alert the clinician on the possibility of thyroid malignancy.

The thyroid: review of imaging features and biopsy techniques with radiologic-pathologic correlation

Knowledge of the normal and abnormal imaging appearances of the thyroid gland is essential for appropriate identification and diagnosis of thyroid lesions. Thyroid nodules are often detected incidentally at computed tomography, magnetic resonance imaging, and positron emission tomography; however, ultrasonography (US) is the most commonly used imaging modality for characterization of these nodules. US characteristics that increase the likelihood of malignancy in a thyroid nodule include microcalcifications, solid composition, and central vascularity. Nuclear scintigraphy is commonly used for evaluation of physiologic thyroid function and for identification of metabolically active and inactive nodules. When fine-needle aspiration biopsy (FNAB) of a lesion is indicated based on clinical and radiologic features, appropriate US-guided biopsy technique and careful cytologic analysis are crucial for making the diagnosis. FNAB and core biopsy are the two percutaneous techniques used to obtain a specimen, with the latter technique being indicated following nondiagnostic or indeterminate FNAB. Specimen adequacy and diagnostic accuracy vary due to several factors, including location of aspiration and biopsy technique used. The radiologist must have a basic knowledge of thyroid disease, be familiar with specimen processing, and recognize the cytologic and radiologic appearances of thyroid lesions, all of which will facilitate the management of these lesions. Online supplemental material is available for this article.

The natural history of the benign thyroid nodule: what is the appropriate follow-up strategy?

BACKGROUND

Long-term monitoring of benign thyroid nodules is not addressed in the present American Thyroid Association guidelines. The objective of this study was to determine the appropriate nature and length of follow-up for patients with a benign thyroid nodule.

STUDY DESIGN

A retrospective review was performed of all patients referred to single endocrine surgeon for evaluation of thyroid nodules between 2006 and 2012. The review included 263 patients who had benign fine needle aspiration (FNA) cytology and either underwent thyroidectomy or had at least a 1-year follow-up ultrasound. Main outcomes measures were repeat FNA and pathology results.

RESULTS

There were 231 women and 32 men. Forty-eight patients underwent immediate thyroidectomy, with pathology showing 2 papillary thyroid cancers (PTC), and 215 patients were followed with annual ultrasounds. During follow-up, 89 (41.3%) nodules underwent repeat FNA after initial biopsy. The repeat FNA cytology showed 91% benign, 7% follicular neoplasm, and 2% PTC. During follow-up, 81 (37.6%) patients underwent thyroidectomy after 3.3±2.8 years. Reasons for surgery included development of symptoms in 58 (71.6%), a non-benign repeat FNA in 8 (9.8%), or patient preference in 15 (18.5%). Surgical pathology identified 70 (86.4%) benign, 7 (8.6%) PTC, 3 (4%) follicular thyroid cancers, and 1 (1.2%) lymphoma. Median time from initial FNA to thyroidectomy in patients who had malignancy was 4.3 years. The maximum initial nodule size and average increase in nodule size did not differ between benign and malignant nodules (p=0.54 and p=0.75, respectively).

CONCLUSIONS

Significant numbers of benign thyroid nodules enlarge more than 5 mm over 3 years, triggering repeat FNA or thyroidectomy. Larger diameter nodules and more rapidly growing nodules were not predictive of malignancy. The practice of annually obtaining ultrasound for benign thyroid nodules should be discouraged.

The use of semi-quantitative ultrasound elastosonography in combination with conventional ultrasonography and contrast-enhanced ultrasonography in the assessment of malignancy risk of thyroid nodules with indeterminate cytology

Background

The pre-surgical selection of thyroid nodules with indeterminate cytology (Thy 3 according to British Thyroid Association) after fine-needle aspiration biopsy (FNAB) is currently required in order to reduce unnecessary total thyroidectomy. The objective of our study was to use a surgical series of Thy 3 nodules to evaluate the predictive role of ultrasound elastosonography (USE) and contrast-enhanced ultrasonography (CEUS) in pre-surgical diagnoses of malignancy.

Subjects and methods

We enrolled 63 patients with Thy 3 nodules in which cytological–histological correlation was available. The ELX 2/1 strain index was obtained by means of semi-quantitative USE, which was performed before surgery in addition to conventional ultrasonography (US) and contrast-enhanced US (CEUS) on the Thy 3 nodules. The ELX 2/1 strain index, a five-item US score and both peak (P) index and time to peak (TTP) index from CEUS were correlated with the histological results. After surgical diagnosis, the data were analysed by using a receiver-operating characteristic (ROC) curve.

Results

Histology was benign in 50 and malignant in 13 Thy 3 nodules. No difference in maximal diameter was noted between benign (22.8 ± 1.6 mm) and malignant (18.9 ± 2.9 mm) nodules. Significant correlations were found between histology and cumulative US findings (p=0.005), ELX 2/1 index (p=0.002), P index (p=0.01) and TTP index (p=0.02). On analysing data from US, USE and CEUS, significant ROC areas under the curve were observed (p<0.0001). A cut-off value was set for US (>2), ELX 2/1 (>0.95), P index (<0.99) and TTP index (>0.98) scores. The diagnostic power of the cumulative pre-surgical analysis of Thy 3 nodules with US, USE and CEUS, considering the experimental cut-off points obtained from the ROC curves was: sensitivity 64%, specificity 92%, PPV 75% and accuracy 84%.

Conclusion

The ELX 2/1 index in conjunction with the US score can be useful in orienting surgical strategies in Thy 3 nodules. The information added by CEUS is less sensitive than that provided by US and USE. The use of a cut-off based on histology can reduce thyroidectomy. Observation should be the first choice when not all instrumental results are suspect.

Imaging, genetic testing, and biomarker assessment of follicular cell-derived thyroid cancer

Thyroid carcinoma is the most common endocrine malignancy worldwide, and its incidence continues to increase. As such the approach to a recently identified thyroid nodule is important to understand. The relevant imaging, examination, and need for fine-needle aspiration biopsy (FNA) are discussed. In approximately 25% of nodules, the diagnosis cannot be established with FNA-based cytology, and surgical excision is necessary for definitive diagnosis. Recent advances in genetic and molecular testing may increase the diagnostic accuracy of FNA in managing thyroid nodules.

Evaluation of thyroid incidentaloma

Thyroid nodules are an extremely common endocrine disorder with a generally accepted prevalence of around 4% to 7%. Incidental thyroid nodules are typically nonpalpable thyroid nodules found during radiographic evaluation for a non-thyroid-related issue (eg, computed tomographic scan, positron emission tomography scan, carotid duplex). Incidental thyroid nodules are contributing to but are not the sole reason for the rising incidence of thyroid cancer in the Unites States and other developed nations.

The Clinical Role of Dual-Time-Point (18)F-FDG PET/CT in Differential Diagnosis of the Thyroid Incidentaloma

Thyroid incidentalomas are common findings during imaging studies including ¹⁸F-fluorodeoxyglucose (¹⁸F-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 ¹⁸F-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 ¹⁸F-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 ¹⁸F-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.

Increases in thyroid nodule fine-needle aspirations, operations, and diagnoses of thyroid cancer in the United States

BACKGROUND

To provide population-based estimates of trends in thyroid nodule fine-needle aspirations (FNA) and operative volumes, we used multiple claims databases to quantify rates of these procedures and their association with the increasing incidence of thyroid cancer in the United States.

METHOD

Private and public insurance claims databases were used to estimate procedure volumes from 2006 to 2011. Rates of FNA and thyroid operations related to thyroid nodules were defined by CPT4 codes associated with International Classification of Diseases, Ninth Revision Clinical Modification codes for nontoxic uni- or multinodular goiter and thyroid neoplasms.

RESULTS

Use of thyroid FNA more than doubled during the 5-year study period (16% annual growth). The number of thyroid operations performed for thyroid nodules increased by 31%. Total thyroidectomies increased by 12% per year, whereas lobectomies increased only 1% per year. In 2011, total thyroidectomies accounted for more than half (56%) of the operations for thyroid neoplasms in the United States. Thyroid operations became increasingly (62%) outpatient procedures.

CONCLUSION

Thyroid FNA and operative procedures have increased rapidly in the United States, with an associated increase in the incidence of thyroid cancer. The more substantial increase in number of total versus partial thyroid resections suggests that patients undergoing thyroid operation are perceived to have a greater risk of cancer as determined by preoperative assessments, but this trend could also increase detection of incidental microcarcinomas.

Management of thyroid incidentalomas encountered by anesthesiologists and pain physicians

Unexpected, asymptomatic thyroid lesions incidentally discovered during unrelated diagnostic or therapeutic interventions are called thyroid incidentalomas (TIs). These lesions are extremely common, creating a clinical problem that most anesthesiologists and pain specialists are unfamiliar with. Ultrasonography (US), which allows high-quality real-time visualization of tissues during brachial plexus block, stellate ganglion block, central vascular access, and other interventions, is the imaging modality of choice of many anesthesiologists and pain medicine specialists for therapeutic interventions on the neck. The increasing number of US procedures performed on the neck will eventually result in an upsurge of anesthesiologists and pain specialists encountering a TI. Interventionalists are responsible for acquiring optimal images, accurate needle positioning during interventions, and storage and appropriate labeling of the obtained images. Ignoring the TI or disclosing the presence of a "tumor" can substantially affect the patient's well-being. In this literature review, we discuss 2 clinical cases of incidentalomas, summarize the current evidence-based strategies, and provide readers with practical guidelines-possibly applicable to other abnormal findings-for the management of incidentally found thyroid lesions.

Increased incidence of thyroid cancer in Latina, Italy: a possible role of detection of subclinical disease

OBJECTIVE

To describe the thyroid cancer incidence trends and geographical patterns in the Latina Province of Lazio, Italy using the population-based cancer registry.

METHODS

We extracted from the Latina cancer registry all cases of thyroid cancer from 1997 to 2006. Cases were classified according to morphological type and diameter. Data for diagnostic procedures for Latina Province residents from 2001 to 2006 were extracted from the regional outpatient procedures information system.

RESULTS

A total of 982 cases were diagnosed, for a standardized incidence of 8.3 and of 27.9 per 100,000 in males (n, 220) and in females (n, 762), respectively. The annual percent change (APC) was +16.7% (95% CI +7.2, +27.2) and +10.5% (95% CI +6.5, +14.6) in males and females, respectively. The increase was mostly due to papillary (n, 759) and small (≤20 mm) cancers (n, 617), with no difference by age (<45 years; n, 431). The APC of neck ultrasound performed was +8.7% (95% CI +0.1, +18.1) and +9.0% (95% CI +1.1, +17.4) and that of biopsy/cytology was +17.0% (95% CI +13.0, +21.3) and +16.6% (95% CI +6.2, +28.1) in men and women, respectively. The geographic pattern of biopsy/cytology was similar to that of cancer incidence but not to that of neck ultrasound.

CONCLUSIONS

In Latina, the increase in thyroid cancer incidence was more rapid than in the rest of Italy, particularly for types with a good prognosis. While tumor size and histotype suggest an increase in detection instead of an increase in disease occurrence, data on diagnostic procedure reimbursements cannot provide an explanation.

The role of positron emission tomography and positron emission tomography/computed tomography in thyroid tumours: an overview

Positron emission tomography (PET) and PET/computed tomography (PET/CT) with different tracers have been increasingly used in patients with thyroid tumours. The aim of this article is to perform an overview based on literature data about the usefulness of PET imaging in this setting. The role of Fluorine-18-Fluorodeoxyglucose (FDG) PET and PET/CT in differentiated thyroid carcinoma (DTC) is well established, particularly in patients presenting with elevated serum thyroglobulin levels and negative radioiodine whole-body scan. Iodine-124 PET and PET/CT may serve a role in staging DTC and obtaining lesional dosimetry for a better and more rationale planning of treatment with Iodine-131. FDG-PET and PET/CT are useful in the post-thyroidectomy staging of high-risk patients with less differentiated histological subtypes. PET and PET/CT with different tracers seem to be useful methods in localizing the source of elevated calcitonin levels in patients with recurrent medullary thyroid carcinoma. Incorporation of FDG-PET or PET/CT into the initial workup of patients with indeterminate thyroid nodules at fine needle aspiration biopsy deserves further investigation. FDG-PET report should suggest further evaluation when focal thyroid incidentalomas are described because these findings are associated with a significant risk of cancer.