Differentiation of thyroid nodules with macrocalcifications: role of suspicious sonographic findings

Cancer rates and characteristics of thyroid nodules with macrocalcification

AIMS

The aim of this study was to determine the malignant potential of thyroid nodules with macrocalcifications and to evaluate the role of other sonographic findings in the diagnosis of malignancy in thyroid nodules besides macrocalcifications.

METHODS

The findings of 8250 patients who applied to our outpatient clinic and underwent thyroid ultrasonography(US) between 2008 and 2021 were retrospectively reviewed. We included a total of 296 patients with 296 macrocalcified nodules (macrocalcification group) and an age- and sex matched group of 300 patients (control group) with the cytopathologic and/or histopathologic data of fine-needle aspiration biopsy (FNAB) of thyroid nodules without calcification. Demographic characteristics of these patients, US characteristics of the nodules, and thyroid function tests were recorded. Cytopathological data of FNAB were classified according to BETHESDA.

RESULTS

The malignancy rate was 14.2% (42/296) in the macrocalcification group and 5.3% (16/300) in the control group (p < 0.001). There was no significant relationship between interrupted peripheral calcification and malignancy. Hypoechoic or markedly hypoechoic appearance, irregular border, solid structure, presence of accompanying pathological lymphadenopathy on sonographic examination and upper and middle zone localization were other sonographic features that increased the risk of malignancy of a nodule. The presence of autoimmunity was not found to be associated with the risk of malignancy. TSH and calcitonin levels of malignant nodules were higher than benign nodules. There was no significant difference between gender and malignancy. In the univariate analysis, it was found that the presence of macrocalcification increased the risk of malignancy 2.935 times. (OR:2.935, p < 0.001.95% CI for OR 1.611-5.349) In addition, being younger, being in the high TIRADS category, and being in the upper and middle zones were factors that increased the risk of malignancy. Gender, TSH level, nodule volume and structure were not associated with malignancy. However, after multivariate analysis, factors that significantly increased the risk of malignancy were younger age, higher TIRADS category, and nodule localization.

CONCLUSION

In our study, the malignancy rate was higher in the macrocalcification group than in the control group. However, no correlation was found after multivariate analysis. In the multivariate analysis, younger age, higher TIRADS category, and nodules located in the upper and middle zone were other factors associated with malignancy. There was no association between peripheral interrupted calcification and malignancy risk.

Association between macrocalcification and papillary thyroid carcinoma and corresponding valuable diagnostic tool: retrospective study

BACKGROUND

Microcalcifications are suggested to be an indicator of thyroid malignancy, especially for papillary thyroid carcinoma (PTC), nonetheless, the association between macrocalcification and PTC is underexplored. Furthermore, screening methods like ultrasonography and ultrasound-guided fine needle aspiration biopsy (US-FNAB) are limited in evaluating macro-calcified thyroid nodules. Thus, we aimed to investigate the relationship between macrocalcification and PTC. We also explored the diagnostic efficiency of US-FNAB and proto-Oncogene Proteins B-raf V600E (BRAF V600E) mutation in macro-calcified thyroid nodules evaluation.

METHODS

A retrospective research of 2645 thyroid nodules from 2078 participants was performed and divided into three groups as non-, micro-, and macro-calcified for further PTC incidence comparison. Besides, a total of 100 macro-calcified thyroid nodules with both results of US-FNAB and BRAF V600E mutation were screened out for subsequent evaluation of diagnostic efficiency.

RESULTS

Compared to non-calcification, macrocalcification showed a significantly higher incidence of PTC (31.5% vs. 23.2%, P<0.05). Additionally, when compared with a single US-FNAB, the combination of US-FNAB and BRAF V600E mutation showed better diagnostic efficiency in diagnosing macro-calcified thyroid nodule (area under the curve (AUC) 0.94 vs. 0.84, P=0.03), with a significantly higher sensitivity (100.0% vs. 67.2%, P<0.01) and a comparable standard of specificity (88.9% vs. 100.0%, P=0.13).

CONCLUSIONS

Occurrence of macrocalcification in thyroid nodules may suggest a high risk of PTC, and the combination of US-FNAB and BRAF V600E showed a greater value in identifying macro-calcified thyroid nodules, especially with significantly higher sensitivity.

TRIAL REGISTRATION

The Ethics Committee of The First Affiliated Hospital of Wenzhou Medical University (2018-026).

The clinical significance of the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) category 5 thyroid nodules: Not as risky as we think?

BACKGROUND

Although the prevalence of thyroid nodules is high, few prove to be malignant. Based on sonographic features, the American College of Radiology Thyroid Imaging Reporting and Data System categorizes malignancy risk of thyroid nodules with associated management recommendations for each category level. Malignancy rates among nodules with a highly suspicious Thyroid Imaging Reporting and Data System category 5 warrant examination in the context of additional risk stratification tools, including cytopathology and molecular testing.

METHODS

All patients who underwent fine-needle aspiration biopsy for Thyroid Imaging Reporting and Data System category 5 nodules from January 2018 to September 2021 in a large integrated academic health system were reviewed. Using the Bethesda System for Reporting Thyroid Cytopathology, categories V and VI were set as malignant. Molecular testing (ThyroSeq version 3; Rye Brook, NY) yielding ≥50% risk of malignancy was deemed positive and correlated with surgical pathology.

RESULTS

A total of 496 Thyroid Imaging Reporting and Data System category 5 nodules were identified. On fine-needle aspiration cytopathology, 61 (12.3%) were malignant. The breakdown included Bethesda System for Reporting Thyroid Cytopathology I, 15 (3%); II, 362 (73%); III, 52 (10.5%); IV, 5 (1%); V, 6 (1.3%); and VI, 55 (11.1%). Of Bethesda System for Reporting Thyroid Cytopathology III/IV nodules with molecular testing (n = 53), 24.5% yielded positive results. In total, 42 (8.5%) nodules underwent surgical resection, most of which were Bethesda System for Reporting Thyroid Cytopathology VI (n = 26, 61.9%). Of excised nodules, 33 (78.6%) nodules were malignant, 6 (14.3%) benign, and 3 (7.1%) noninvasive follicular thyroid neoplasm with papillary-like nuclear features. All Thyroid Imaging Reporting and Data System category 5 nodules with malignant cytology (Bethesda System for Reporting Thyroid Cytopathology V/VI) that underwent surgery were malignant on histopathology. On average, the total Thyroid Imaging Reporting and Data System points were higher in malignant nodules compared with benign (9.3 vs 7.3; P = .015). Moreover, benign nodules more frequently received Thyroid Imaging Reporting and Data System points when the radiologist was unable to determine composition or echogenicity (33% vs 3% among malignant nodules; P = .01).

CONCLUSION

Thyroid Imaging Reporting and Data System category 5 designation in thyroid nodules is associated with a lower risk of malignancy than previously reported. Benign and malignant nodules with Thyroid Imaging Reporting and Data System category 5 designation have discrepancies in certain Thyroid Imaging Reporting and Data System characteristics and individual points assigned, which may offer an opportunity for quality improvement and standardization measures in ultrasound reporting practices.

Incorporation of a machine learning pathological diagnosis algorithm into the thyroid ultrasound imaging data improves the diagnosis risk of malignant thyroid nodules

Objective

This study aimed at establishing a new model to predict malignant thyroid nodules using machine learning algorithms.

Methods

A retrospective study was performed on 274 patients with thyroid nodules who underwent fine-needle aspiration (FNA) cytology or surgery from October 2018 to 2020 in Xianyang Central Hospital. The least absolute shrinkage and selection operator (lasso) regression analysis and logistic analysis were applied to screen and identified variables. Six machine learning algorithms, including Decision Tree (DT), Extreme Gradient Boosting (XGBoost), Gradient Boosting Machine (GBM), Naive Bayes Classifier (NBC), Random Forest (RF), and Logistic Regression (LR), were employed and compared in constructing the predictive model, coupled with preoperative clinical characteristics and ultrasound features. Internal validation was performed by using 10-fold cross-validation. The performance of the model was measured by the area under the receiver operating characteristic curve (AUC), accuracy, precision, recall, F1 score, Shapley additive explanations (SHAP) plot, feature importance, and correlation of features. The best cutoff value for risk stratification was identified by probability density function (PDF) and clinical utility curve (CUC).

Results

The malignant rate of thyroid nodules in the study cohort was 53.2%. The predictive models are constructed by age, margin, shape, echogenic foci, echogenicity, and lymph nodes. The XGBoost model was significantly superior to any one of the machine learning models, with an AUC value of 0.829. According to the PDF and CUC, we recommended that 51% probability be used as a threshold for determining the risk stratification of malignant nodules, where about 85.6% of patients with malignant nodules could be detected. Meanwhile, approximately 89.8% of unnecessary biopsy procedures would be saved. Finally, an online web risk calculator has been built to estimate the personal likelihood of malignant thyroid nodules based on the best-performing ML-ed model of XGBoost.

Conclusions

Combining clinical characteristics and features of ultrasound images, ML algorithms can achieve reliable prediction of malignant thyroid nodules. The online web risk calculator based on the XGBoost model can easily identify in real-time the probability of malignant thyroid nodules, which can assist clinicians to formulate individualized management strategies for patients.

Atypia of undetermined significance/follicular lesions of undetermined significance: What radiologists need to know

Atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS) refers to an intermediate histologic category of thyroid nodules in The Bethesda System for Reporting Thyroid Cytopathology. Although the risk of malignancy in this category was originally cited as 5-15%, recent literature has suggested higher rates of related malignancy ranging from 38% to 55%. Malignant nodules warrant surgery with total thyroidectomy or thyroid lobectomy, whereas benign nodules can be observed or followed with serial ultrasounds (US) based on their imaging characteristics. The management of nodules with a cytopathologic diagnosis of AUS/FLUS can be difficult because theses nodules lie between the extremes of benign and malignant. The management options for such nodules include observation, repeat fine-needle aspiration, and surgery. The use of molecular genetics, the identification of suspicious US characteristics, and the recognition of additional clinical factors are all important in the development of an appropriate, tailored management approach. Institutional factors also play a crucial role.

Nodule Size Effect on Diagnostic Performance of Ultrasonography and Computed Tomography for Papillary Thyroid Carcinoma

BACKGROUND

To compare the abilities of ultrasonography (US) and Computed Tomography (CT) to identify calcifications and to predict probability of malignancy for Papillary Thyroid Carcinoma (PTC) and Papillary Thyroid Microcarcinoma (PTMC).

METHODS

We reviewed 1008 cases of PTC/PTMC with calcifications reported by pre-operative US, CT, or post-operative pathology. The size of the thyroid nodule was obtained from the US report and the maximum diameter (d) was documented. According to the nodule size (d), the PTC and PTMC groups were each divided into two subgroups, as follows: large PTC group (d ≥ 2 cm), small PTC group (1 cm < d < 2 cm), large PTMC group (0.6 cm ≤ d ≤ 1 cm), and small PTMC group (d < 0.6 cm).

RESULTS

In the 1008 patients, the ratio of females to males was 2.29 and the mean age was 40.9 years (standard deviation: 11.7 years). Of the 1008 records, 92.8% were found to have calcifications according to the US report, while 50.4% showed calcifications according to the CT report. This difference between US and CT reports was statistically significant (p < 0.0005). The percentages of US reports showing calcifications were similar for all four PTC and PTMC subgroups (93.7%, 94.3%, 92.1%, and 85.1%, respectively; p = 0.052), while the percentages of CT reports showing calcifications were significantly different among the PTC and PTMC subgroups (62.3%, 52.2%, 45.4%, and 31.3%, respectively; p < 0.0005). As for the prediction of malignancy, US was superior to CT in all four subgroups (large PTC group: 97.1% vs. 54.1%, small PTC group: 94.8% vs. 42.9%, large PTMC group: 97.2% vs. 32.0%, small PTMC group: 95.5% vs. 14.9%; p < 0.0005 for all pairwise comparisons). No significant difference was observed in terms of the ability of US to predict the malignancy of PTC versus PTMC (p = 0.31), while CT showed significant superiority in diagnosing PTC versus PTMC (p < 0.0005). The predictive value of CT for PTC declined as the nodule size decreased (p < 0.05 for all pairwise comparisons).

CONCLUSION

Our results showed that US detected calcifications and predicted the malignancy of all nodule sizes of thyroid papillary carcinoma equally well, while the performance of CT declined with the reduction of nodule size.

99mTc-Methylene Diphosphonate Uptake in Soft Tissue Tumors on Bone Scintigraphy Differs Between Pediatric and Adult Patients and Is Correlated with Tumor Differentiation

Objective

To analyze the difference in ^99mTc-methylene diphosphonate (MDP) uptake on bone scintigraphy in extraosseous soft tissue tumors between children and adults and the correlation between tracer uptake and tumor differentiation and histopathology.

Methods

Patients with neoplasms with MDP uptake were retrospectively identified. Based on histopathology, tumors were categorized as epithelial malignant tumors, mesenchymal tumors, blastomas and germ cell tumors. The degree of radioactivity accumulation in lesions relative to the uptake in ribs and sternum or spine was classified as “+”, “++” and “+++”. The results were compared between children and adults. The correlations between MDP uptake in soft tumors and tumor differentiation and pathology were investigated.

Results

Extraosseous soft tissue tumors that accumulated MDP were found in 33 children and 31 adults. In children, neuroblastoma was the most common extraosseous soft tissue tumor that accumulated MDP; in adults, MDP uptake was mostly found in lung cancer. MDP uptake in pediatric soft tissue tumors was higher than that in adults. MDP uptake in extraosseous soft tissue tumors with different histopathologic classifications was significantly different among 64 patients. In 41 patients with available tumor differentiation data from histopathology, MDP uptake in low or poorly differentiated soft tumors was higher than that in the moderately or well-differentiated lesions. Necrosis and/or calcifications were showed in most of pediatric and adult neoplasms.

Conclusion

Significant elevations in MDP uptake in extraosseous soft tissue tumors are associated with poorly differentiated tumors in both children and adults. The mechanism of bone tracer uptake in pediatric and adult neoplasms was mostly related to necrosis and/or necrosis and calcification. The extraosseous soft tissue tumors with MDP uptake in pediatric patients were different from those in adults. In addition, consistent with the inherent degree of tumor malignancy, MDP uptake in children was higher than that in adults.

Peripheral Thyroid Nodule Calcifications on Sonography: Evaluation of Malignant Potential

OBJECTIVE. The purpose of this study is to assess the association of thyroid cancer with sonographic features of peripheral calcifications. MATERIALS AND METHODS. We retrospectively reviewed patients who had a total of 97 thyroid nodules with peripheral calcifications who underwent ultrasound-guided fine-needle aspiration from 2008 to 2018. Three board-certified radiologists evaluated the nodules for features of peripheral calcifications: the percentage of the nodule involved by peripheral calcifications, whether the calcifications were continuous or discontinuous, the visibility of internal components of the nodule, and the presence of extrusion of soft tissue beyond the calcifications. The correlation of peripheral calcification parameters with the rate of thyroid nodule malignancy was evaluated. In addition, the interobserver agreement between readers was assessed with Cohen kappa coefficient. RESULTS. Of the 97 nodules with peripheral calcifications, 27% (n = 26) were found to be malignant on biopsy. The continuity of peripheral calcifications, visibility of internal components, and extrusion of soft tissue beyond the calcification rim showed no significant association with benign or malignant nodules. Readers had good agreement on peripheral calcification continuity (κ = 0.63; 95% CI, 0.53-0.73) and moderate agreement on internal component visibility (κ = 0.43; 95% CI, 0.35-0.51) and percentage of the nodule involved by rim calcifications (κ = 0.52; 95% CI, 0.44-0.59). There was fair agreement for extranodular soft-tissue extrusion (κ = 0.32, 95% CI, 0.24-0.39). CONCLUSION. Peripheral rim calcifications are highly associated with malignancy. However, specific peripheral rim calcification features do not aid in distinguishing benign from malignant nodules, which may in part be caused by high interobserver variability.

Echogenic foci in thyroid nodules: diagnostic performance with combination of TIRADS and echogenic foci

Background

The malignancy risks of various echogenic foci in thyroid nodules are not consistent. The association between malignancy and echogenic foci and various Thyroid Imaging Reporting and Data System (TIRADS) in thyroid nodules has not been evaluated. We evaluated the malignancy probability and diagnostic performance of thyroid nodules with various echogenic foci and in combination with TIRADS.

Methods

This retrospective study was approved by Institutional Review Board. The data were retrospectively collected from January 2013 to December 2014. In total, 954 patients (mean age, 50.8 years; range, 13–86 years) with 1112 nodules were included. Using χ² test, we determined the prevalence of benign and malignant nodules among those with and without echogenic foci; we associated each of 6 echogenic foci types with benign and malignant nodules. Diagnostic performance was compared between the 6 types alone and in combination with various TIRADS.

Results

Among 1112 nodules, 390 nodules (35.1%) were found to have echogenic foci, and 722 nodules (64.9%) were not. Among nodules with echogenic foci, 254 nodules (65.1%) were malignant. The punctate echogenic foci with comet-tail artifact showed malignancy rate of 77.8% in solid and predominantly solid nodules. Our study demonstrated relatively low PPV (33.3–56.4%) in nodules with large echogenic foci without shadowing, macrocalcification, and peripheral curvilinear or eggshell echogenic foci with or without shadowing. However, when combined with high suspicion category of TIRADS, PPV increased to 50.0–90.9%.

Conclusion

Combination with TIRADS with different types of echogenic foci offer better stratification of the malignancy risk.

Electronic supplementary material

The online version of this article (10.1186/s12880-019-0328-2) contains supplementary material, which is available to authorized users.

Clinical Diagnostic Evaluation of Thyroid Nodules

The presence of a thyroid nodule may be recognized by the patient or the clinician on palpation of the neck or it may be an incidental finding during an imaging study for some other indication. The method of detection is less important, however, than distinguishing benign lesions from more aggressive neoplasms. This article outlines the diagnostic algorithm for the evaluation of thyroid nodules including biochemical testing, imaging, and, when appropriate, fine-needle aspiration. In addition, the authors review the natural history of benign nodules, follow-up strategies, and indications for repeat aspiration.

Subclassification of Bethesda Atypical and Follicular Neoplasm Categories According to Nuclear and Architectural Atypia Improves Discrimination of Thyroid Malignancy Risk

BACKGROUND

Although The Bethesda System for Reporting Thyroid Cytopathology has provided clinicians with a standardized classification scheme for the diagnosis of thyroid fine-needle aspiration cytology (FNAC) specimens, the indeterminate categories of Bethesda III (B3)-atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS)-and Bethesda IV (B4)-follicular neoplasm/suspicious for follicular neoplasm (FN/SFN)-continue to pose challenges with regards to ideal diagnostic and therapeutic management. Having previously demonstrated the presence of nuclear atypia as a high-risk subgroup in B3, the objective of this study was to evaluate the malignancy rates in the B4 subgroup with nuclear atypia.

METHODS

A retrospective review of all thyroid FNACs diagnosed as B4 (FN/SFN) between 2008 and 2015 was conducted at a tertiary referral center in Singapore. Data on patient demographics, sonographic features, and final histological diagnosis were collected. This was compared to data from a previous analysis on all nodules diagnosed as B3 (AUS/FLUS) over a similar period.

RESULTS

A total of 137/309 (44.3%) and 88/111 (79.3%) FNACs diagnosed as B3 and B4, respectively, underwent surgical excision yielding final histopathological diagnoses. The malignancy rate of B4 was 31/88 (35.2%) compared to B3, which was 37/137 (27.0%). Subclassification based on the presence of architectural versus nuclear atypia showed significantly higher malignancy rates in B4 nodules with nuclear atypia (21.8% vs. 57.6%; p < 0.01). These findings corroborate previous results within the B3 category (malignancy rate of 14.7% vs. 36.8%; p < 0.01). The only sonographic features predictive of malignancy were the presence of macrocalcifications in B4 compared to irregularity of margins in B3.

CONCLUSION

The presence of nuclear atypia identifies subgroups with significant differential malignancy risks within both the B3 and B4 categories. This supports the notion that subclassification is a useful risk stratification tool that can guide diagnostic and therapeutic management of indeterminate thyroid nodules with heterogenous risk profiles.

Thyroid Cancer: Ultrasound Imaging and Fine-Needle Aspiration Biopsy

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

ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee

classification that is widely used in breast imaging, their authors chose to apply the acronym TI-RADS, for Thyroid Imaging, Reporting and Data System. In 2012, the ACR convened committees to (1) provide recommendations for reporting incidental thyroid nodules, (2) develop a set of standard terms (lexicon) for ultrasound reporting, and (3) propose a TI-RADS on the basis of the lexicon. The committees published the results of the first two efforts in 2015. In this article, the authors present the ACR TI-RADS Committee's recommendations, which provide guidance regarding management of thyroid nodules on the basis of their ultrasound appearance. The authors also describe the committee's future directions.

Is Ultrasonography More Sensitive Than Computed Tomography for Identifying Calcifications in Thyroid Nodules?

OBJECTIVES

The primary objective of this study was to evaluate the difference and agreement between ultrasonography (US) and computed tomography (CT) for identifying calcifications in thyroid nodules.

METHODS

Data from the medical records of 20,248 patients were reviewed for preoperative diagnostic investigations and postoperative pathologic diagnoses. In total, 5247 records were selected for analysis based on the presence of calcifications reported in any of the following 3 modes: US, CT, and pathologic analysis. All 5247 patients underwent US examinations, whereas 3827 underwent cervical CT examinations. All patients had a postoperative pathologic diagnosis serving as a reference. The value of US for identification of calcifications and prediction of malignancy was analyzed on the basis of the entire cohort of 5247 records, whereas that of CT was based on 3827 records. The agreement between US and CT was analyzed on the basis of the 3827 common records.

RESULTS

Of the 5247 patients who underwent US, 4855 (92.5%) were found to have calcifications, whereas of the 3827 patients who underwent CT, 2040 (53.3%) were found to have calcifications (P < .0005). Among the 404 cases with calcifications reported by pathologic analysis, the agreement rate between US and pathologic findings was significantly higher than that between CT and pathologic findings (87.9% versus 81.9%, respectively; P = .018).

CONCLUSIONS

US is more sensitive and accurate than CT for detecting calcifications in thyroid nodules. Hence, US is recommended as the preferred imaging modality for calcification detection in thyroid nodules.

Computerized analysis of calcification of thyroid nodules as visualized by ultrasonography

OBJECTIVE

The purpose of this study is to quantify computerized calcification features from ultrasonography (US) images of thyroid nodules in order to determine the ability to differentiate between malignant and benign thyroid nodules.

METHODS

We designed and implemented a computerized analysis scheme to quantitatively analyze the US features of the calcified thyroid nodules from 99 pathologically determined calcified thyroid nodules. Univariate analysis was used to identify features that were significantly associated with tumor malignancy, and neural-network analysis was performed to classify tumors as benign or malignant. The diagnostic performance of the neural network was evaluated using receiver operating characteristic (ROC) analysis, where in the area under the ROC curve (Az) summarized the diagnostic performance of specific calcification features.

RESULTS

The performance values for each calcification feature were as follows: ratio of calcification distance=0.80, number of calcifications=0.68, skewness=0.82, and maximum intensity=0.75. The combined value of the four features was 0.84.With a threshold of 0.64, the Az value of calcification features was 0.83 with a sensitivity of 83.0%, specificity of 82.4%, and accuracy of 82.8%.

CONCLUSIONS

These results support the clinical feasibility of using computerized analysis of calcification features from thyroid US for differentiating between malignant and benign nodules.

Sonographic features of medullary thyroid carcinomas according to tumor size: comparison with papillary thyroid carcinomas

OBJECTIVES

The aim of this study was to evaluate the differences in sonographic features of medullary thyroid carcinomas according to nodule size and compared with findings for papillary thyroid carcinomas.

METHODS

This study included 38 medullary thyroid carcinoma nodules and 91 papillary thyroid carcinoma nodules, which were confirmed by pathologic examination between May 2008 and September 2013. Nodules were divided into those that were greater than 10 mm (large nodules) and 10 mm or less (small nodules). The differences in sonographic features (composition, echogenicity, margin, calcifications, and shape) between groups were analyzed with a χ(2) test.

RESULTS

Large medullary thyroid carcinomas more frequently showed an ovoid-to-round shape and a smooth margin; small medullary thyroid carcinomas more frequently showed a taller-than-wide shape and a spiculated margin; the differences were statistically significant between the groups (P < .05). Compared with papillary thyroid carcinomas, large medullary thyroid carcinomas tended to have an ovoid-to-round shape, a smooth margin, and macrocalcifications and were more frequently diagnosed as indeterminate nodules (P < .05); however, there were no significant differences in the internal composition, calcifications, echogenicity, margin, and shape between small medullary thyroid carcinomas and small papillary thyroid carcinomas (P > .05).

CONCLUSIONS

Our data indicate that the sonographic features of medullary thyroid carcinomas are associated with tumor size; furthermore, the sonographic features of medullary thyroid carcinomas are similar to those of small papillary thyroid carcinomas but greatly different from those of large papillary thyroid carcinomas. Large medullary thyroid carcinomas are more commonly diagnosed as indeterminate nodules by sonography than large papillary thyroid carcinomas, and fine-needle aspiration biopsy or serum calcitonin measurement may be helpful.

Characterization of papillary thyroid microcarcinomas using sonographic features in malignant papillary thyroid cancer: a retrospective analysis

The diagnosis of malignant thyroid nodules is still a clinical challenge. This study aimed to determine the ultrasonographic characteristics of papillary thyroid carcinoma. The ultrasonographic and pathological data of 2453 thyroid nodules in a cohort of 1895 Chinese patients who underwent thyroidectomy from January 2010 to December 2012 were retrospectively reviewed. Anteroposterior and transversal (AP/TR) diameters ≥1, solid structure, infiltrative margins, hypoechoic appearance, and microcalcifications were more common in malignant nodules than in benign nodules (P < 0.01). These ultrasonographic features were independent risk factors of malignancy (P < 0.01) as determined by logistic regression analysis. Based on multivariate analysis, these characteristics were also present in large nodules (diameter >10 mm). However, in small nodules (diameter ≤10 mm), only AP/TR ≥1 and infiltrative margins were independent risk factors of malignancy (P < 0.01). Ultrasonography is of high diagnostic value for malignant thyroid nodules and may help to improve the differential diagnosis. Small and large nodules have distinct ultrasonographic features.

The sonographic appearance of benign and malignant thyroid diseases and their histopathology correlate: demystifying the thyroid nodule

The thyroid gland is one of the largest endocrine glands in the human body. It functions as a regulator of metabolism. Diseases involving the thyroid range from benign to malignant and can be associated with major morbidity and mortality. Ultrasound (US) imaging of the thyroid gland is prompted because of a palpable mass on clinical examination; abnormality of thyroid function tests; incidental finding on other imaging modalities, that is, nuclear scintigraphy or computed tomography scan; screening for patients with risk factors for malignancy, such as multiple endocrine neoplasia type II; or prior neck radiation treatment.Ultrasound is an excellent, noninvasive, and cost-effective diagnostic tool in the detection and characterization of thyroid disease. Most thyroid diseases have pathognomonic features on US, which are of diagnostic importance and lead to appropriate clinical management. Ultrasound plays an important role in differentiating benign from malignant thyroid disease, thereby triaging patients for US-guided fine-needle aspiration. Ultimately, thyroid US, in conjunction with thyroid function tests, can aid in characterizing various thyroid diseases.The main objective of this pictorial essay is to illustrate the sonographic appearance of various benign and malignant diseases of the thyroid with their histopathology correlations. Management of thyroid nodules using US-guided fine-needle aspiration is also briefly discussed.

Thyroid nodules with macrocalcification: sonographic findings predictive of malignancy

PURPOSE

To analyze which sonographic features of thyroid nodules with macrocalcifications were predictable of thyroid malignancy.

MATERIALS AND METHODS

We reviewed sonographic findings of 854 macrocalcified thyroid nodules in patients who underwent fine needle aspiration biopsy between December 2009 and January 2011. There were 171 non-diagnostic aspirations, 34 nodules with category 3, 4, 5 based on Bethesda system, which were not confirmed by surgery, and these nodules were excluded from the analysis. Sonographic characteristics of the macrocalcifications including its thickness, interruption, and existence of soft tissue rim outside the macrocalcification were analyzed. Other sonographic characteristics of nodules such as shape, margin, composition, echo pattern, vascularity, and underlying parenchymal echogenicity were also evaluated. The correlation of sonographic features with cytopathologic results and the diagnostic performance of sonographic features for the prediction of malignancy were analyzed.

RESULTS

Among 649 nodules, 179 (27.6%) nodules were malignant and 470 (72.4%) nodules were benign. Among the features of the macrocalcification, interruption, irregular thickness, or the presence of soft tissue outside calcification rim were associated with malignancy (p<0.001). A high sensitivity and negative predictive values for the prediction of malignancy was found in sonographic characteristics of irregular thickness (92.2% and 91.0%, respectively) and the presence of soft tissue (88.5% and 88.8%, respectively).

CONCLUSION

Sonographic characteristics of macrocalcification such as interruption, irregular thickness and the presence of soft tissue rim were associated with malignancy in thyroid nodules with macrocalcifications.

Hürthle cell thyroid adenoma with an eggshell calcification: sonographic-pathologic correlation

We report the sonographic pathologic correlation in a case of Hürthle cell thyroid adenoma with an eggshell calcification in a 58-year-old woman. The mass was hypoechoic with a continuous eggshell calcification on gray-scale sonographic and intranodular vascularity power Doppler imaging. At pathological examination, the dystrophic calcification of eggshell type was located between the intact fibrous capsule and the main tumor matrix. Hürthle cell adenoma should be included in the differential diagnosis of a thyroid nodule with an eggshell calcification.

Papillary thyroid carcinoma with honeycomb-like multiple small cysts: characteristic features on ultrasonography

BACKGROUND

Thyroid nodules with cystic content or mixed sponge-like aspect on ultrasonography and a concordant cytology are strongly predictive of benignity.

OBJECTIVES

We present 8 patients with honeycomb-like papillary thyroid carcinoma with multiple small cysts on ultrasonography.

METHODS

The patients were 6 women and 2 men aged between 30 and 57 years. The tumors of these patients showed honeycomb-like multiple small cysts that were aggregated in some area of the thyroid gland on ultrasonography. Histopathological examination indicated a well-differentiated type of papillary thyroid carcinoma with multiple small cysts and a small solid lesion. The cysts were lined with papillary carcinoma cells, and normal thyroid tissue lay between the cysts.

RESULTS

There is a peculiar type of papillary thyroid carcinoma that histopathologically shows honeycomb-like multiple small cysts in the thyroid gland. Ultrasonography can be used to identify characteristic features of honeycomb-like multiple small cysts in the thyroid gland in such patients.

CONCLUSIONS

One should be aware of this peculiar type of papillary thyroid carcinoma with honeycomb-like multiple small cysts on ultrasonography, although thyroid nodules with cystic lesions are generally regarded as benign in clinical management.

Utility of gray-scale ultrasound to differentiate benign from malignant thyroid nodules

Objective:

The objective was to assess the utility of gray-scale USG to identify patterns of thyroid nodules and to correlate the characteristics of benign and malignant nodules with pathological diagnosis.

Materials and Methods:

From September 2009 to August 2010, a total of 203 patients (17 males and 186 females), with 240 nodules detected at USG, were included in this study. The characteristics of each nodule were determined. The results were then compared with fine needle aspiration (FNA)/histopathological diagnosis.

Results:

Of the 240 nodules examined, 44 (18.33%) were found to be malignant on cytopathology. The malignant nodules demonstrated solid or predominantly solid composition (sensitivity 88.6%, specificity 53.5%); presence of microcalcification (sensitivity 65.9%, specificity 97.9%); irregular or poorly defined margins (sensitivity 84%, specificity 88.7%); anteroposterior (AP) diameter > transverse diameter (sensitivity 77.2%, specificity 80.1%); absent or thick incomplete halo (sensitivity 70.4%, specificity 65.8%); and markedly hypoechoic character (sensitivity 65.9%, specificity 84.6%). Among males, malignant nodules were found in 36.8%, whereas in females the occurrence was 16.7%.

Conclusion:

Gray-scale USG features of thyroid nodules are useful to distinguish patients with clinically significant thyroid nodules from those with innocuous nodules despite the overlap of findings. From our study, it is apparent that the USG findings of poorly defined margins, marked hypoechogenicity, microcalcifications, and a taller-than-wider shape have a high diagnostic accuracy for identifying malignant thyroid nodules.

Follicular thyroid adenoma with eggshell calcification presenting as an intensely hypermetabolic lesion on 18F-FDG PET/CT

We report herein a case of follicular thyroid adenoma with an eggshell calcification presenting as an intensely hypermetabolic lesion on combined (18)F-fluorodeoxyglucose whole-body PET and CT ((18)F-FDG PET/CT) performed for staging work-up in a 68-year-old woman who had undergone distal gastrectomy with Billroth II anastomosis for early gastric carcinoma. The mass was intensely hypermetabolic (SUV(max) = 21.3 g/mL) on combined (18)F-FDG PET/CT, hypoechoic with an interrupted eggshell calcification on gray-scale ultrasonography (US), and showed intranodular vascularity on power Doppler US. Follicular adenoma should be considered in the differential diagnosis of a mass with an eggshell calcification on US and intense hypermetabolism on (18)F-FDG PET/CT.

Follicular thyroid carcinoma with an eggshell calcification: report of 3 cases

OBJECTIVE

The purpose of this series is to report 3 cases of follicular thyroid carcinoma with an eggshell calcification along with their imaging findings.

METHODS

Imaging findings on gray scale and power Doppler (PD) sonography (n = 3), computed tomography (CT; n = 3), and integrated fluorodeoxyglucose F 18 ((18)F-FDG) whole-body positron emission tomography (PET)/CT (n = 1) were assessed.

RESULTS

Of the 3 cases, two 75-year-old women had bone metastasis, and one 54-year-old woman had a thyroid incidentaloma on sonography. All 3 cases had a spherical mass with an interrupted eggshell calcification on gray scale sonography and CT; 2 revealed intranodular vascularity on PD sonography, and 1 showed intense hypermetabolism (maximum standardized uptake value, 7.9 g/mL) on integrated (18)F-FDG whole-body PET/CT.

CONCLUSIONS

Follicular carcinoma should be considered in the differential diagnosis of a thyroid nodule with an eggshell calcification.

Sonographic differentiation of thyroid nodules with eggshell calcifications

OBJECTIVE

The purpose of this study was to assess the role of known suspicious sonographic findings and to find other additional sonographic findings to differentiate benign and malignant thyroid nodules with "eggshell" calcifications.

METHODS

Our Institutional Review Board approved this retrospective study, and informed consent was not required. We reviewed sonographic findings of thyroid nodules in 795 patients who underwent thyroid surgery in our institution between August 2006 and February 2007. Ninety-three thyroid nodules with eggshell calcifications in 92 patients were included in this study. Each lesion was evaluated for known suspicious sonographic criteria, including marked hypoechogenicity, irregular or microlobulated margins, and a taller-than-wide shape, as well as 2 additional sonographic findings: a hypoechoic halo and disruption of eggshell calcifications (halo and disrupted calcification rim). The sensitivity and specificity based on the sonographic criteria were calculated and compared among the 2 types of criteria.

RESULTS

Among the 93 thyroid nodules, 59 were malignant and 34 were benign. The halo and disrupted calcification rim showed higher sensitivity (62.7% and 76.3%, respectively) than any of the known suspicious sonographic criteria (40.7%, 35.6%, and 55.9%). The combination of both the halo and the disrupted calcification rim showed significantly higher sensitivity (93.2%) than the combination of the known suspicious sonographic criteria (78%; P < .05), although both had the same specificity (64.7%).

CONCLUSIONS

In thyroid nodules with eggshell calcifications but no other calcifications, the findings of a peripheral halo and disruption of the eggshell calcifications may be more useful sonographic predictors of malignancy than hypoechogenicity, microlobulated margins, and a taller-than-wide shape.