Submitted:
12 July 2024
Posted:
15 July 2024
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Abstract
Introduction: Thyroid nodules are extremely common and require complex management to prevent unnecessary surgical intervention and ensure that no malignant disease is overlooked. Several diagnostic tools and scoring systems are available to evaluate the Risk of Malignancy (ROM). The goal is to assess variables that can aid and support the clinical recommendations suggested by the updated Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), such as the ultrasonographic features of thyroid nodules, particularly for indeterminate categories III (atypia of undetermined significance) and IV (follicular neoplasm). Methods: We retrospectively analysed the correlation of the demographic and ultrasonographic characteristics of thyroid nodules with the cytopathological and histopathological diagnoses of TBSRTC categories III (atypia of undetermined significance), IV (follicular neoplasm), V (suspicious for malignancy), and VI (malignant) in patients who underwent surgery in a single Portuguese centre over a 10-year period. Results: In total, 360 nodules were evaluated in 341 patients and 57% were histopathologically malignant or borderline. The majority were included in the TBSRTC indeterminate categories III and IV with an ROM of 44% and 43%, respectively. The ultrasonographic characteristics associated with a higher TBSRTC category and a greater ROM value were hypoechogenicity, presence of microcalcifications, irregular margins, and the presence of cervical adenopathy. When correlating with a malignant histology, only adenopathy and the presence of microcalcifications were observed to be statistically significant. Discussion: The indeterminate categories of the TBSRTC have been the most challenging ones to manage. The new TBSRTC (2023) guidelines as well as the ultrasonographic characteristics of a patient can be helpful in assessing the ROM and deciding on an appropriate course of treatment. Other resources, such as molecular tests, are also gaining a more important role in the clinical decision process and may become crucial in the future. Conclusion: The clinical management of thyroid nodules requires a careful analysis of clinical history and an evaluation of demographic details, the symptoms of the patient, comorbidities, personal and family history, ultrasonographic features, and the results of cytopathology, thyroid function, and molecular/genetic tests to provide the best care possible. Patients with thyroid nodules of an indeterminate character can obtain a definitive diagnosis through surgery. However, by employing a complete analysis of all relevant data, some patients may be suitable for active surveillance instead of a surgical intervention.
Keywords:
the bethesda system for reporting thyroid cytopathology
; thyroid nodules
; risk of malignancy
; grey area
; ultrasonographic characteristics
Introduction
Thyroid nodules are extremely common and are present in 19%-68% of randomly selected individuals subjected to thyroid ultrasonography. However, only a small percentage of these (7%-15%) constitute thyroid cancer. [1]Ultrasonography is the most widely used imaging modality for the assessment of thyroid diseases. It is an easily available, inexpensive, and radiation-free diagnostic tool that allows for the evaluation of the thyroid parenchyma, measurement of size, location, and characterisation of nodules, and evaluation of cervical lymph nodes. Thyroid nodules are evaluated based on their size, echogenicity, presence of calcifications, shape (taller-than-wide), vascularity, halos, and margins. [2] Since none of these yield results that are 100% predictive of thyroid cancer and ultrasonography has poor reproducibility with significant inter- and intra-operator variability, several classification systems have been proposed by medical researchers to aid the decision to perform ultrasonographically guided fine needle aspiration cytology (FNAC), estimating the risk of thyroid cancer. One such cancer risk assessment system is termed the Thyroid Imaging Reporting and Data System (TI-RADS) and is named after the widely accepted Breast Imaging Reporting and Data System used for breast imaging. Several versions of TI-RADS, such as the European Thyroid Association (EU TI-RADS), the American College of Radiology TI-RADS, the Chinese TI-RADS, and the Korean Society of Thyroid Radiology TI-RADS have been validated and have demonstrated diagnostic value in predicting thyroid malignancy. However, the studies conducted for these validations were mostly retrospective and showed poor reproducibility owing to the variability in operators and equipment. For EU TI-RADS category 5 (high-risk: at least one of the following features: irregular shape, irregular margins, microcalcifications, or marked hypoechogenicity), the estimated malignancy risk according to the European Thyroid Association guidelines is 26%-87%.
The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was created to report thyroid cytopathology after FNA, categorise the Risk of Malignancy (ROM), and standardise the management of thyroid nodules. [3] There are six TBSRTC categories: I - Non-Diagnostic (ND); II – Benign (B); III - Atypia of Undetermined Significance (AUS); IV - Follicular Neoplasm (FN); V, Suspicious for Malignancy (SM); and VI – Malignant (M), each associated with clinical recommendations. The TBSRTC categories III (AUS) and IV (FN) are termed the indeterminate categories, with ROMs that vary greatly in the literature, and present the most challenging clinical management decisions. [3] Current guidelines suggest repeating FNAC, molecular testing, or lobectomy for AUS, and molecular testing or lobectomy for FN. [4] Even with the updated 3rd version of the TBSRTC, published in 2023 that further scrutinises these categories, the management of these nodules remains challenging.[4]
Combining the ultrasonography-based overdiagnosis of thyroid nodules with the lack of a clear course of action associated with TBSRTC categories III (AUS) and IV (FN) may result in the unnecessary surgical excision of benign nodules, thereby exposing patients to the potential risks of a surgical procedure and its complications.
This study aimed to assess variables (such as clinical, demographic, and ultrasonographic characteristics) that can aid in deciding between a surgical or active surveillance approach for the indeterminate TBSRTC categories, supporting and complementing the recommendations provided by the updated TBSRTC and its new ROMs.
Methods
Study Design and Participants
A retrospective review was carried out of all patients who underwent FNAC, whose cytopathology corresponded to TBSRTC categories III, IV, V, and VI, and who underwent partial or total thyroidectomy in the Endocrine Surgery Section, Department of General Surgery, of a single Portuguese hospital, over a 10-year period (between January 2009 and January 2019).
Only patients who underwent all cytological examinations, surgery, and histopathological analyses at the hospital were included in the study sample. Data were accessed from the hospital records for research purposes in 2019 (June to December).
Measurements
Patient age, sex, type of surgery, number of nodules evaluated, ultrasonographic characteristics, and cytological and histological diagnoses of the nodules were recorded, and the ROM was calculated.
The results of ultrasonography and the FNAC findings were reviewed by a single endocrine surgeon.
Statistical Analysis
A statistical analysis was performed using the SPSS PASW Statistics 18 software package, release version 18.0.0, by employing a Pearson chi-square independence test. This test uncovers the relationship between two categorical variables, where each variable can have two or more categories. It considers a crosstabulation table, with cases classified according to the categories in each variable. This work considered two crosstabulation tables: (1) between the ultrasonography characteristics and the cytopathological classification and (2) between the ultrasonography characteristics and the histological classification.
The null hypothesis states there is no association between the two variables, while the alternative hypothesis states there is an association. To obtain the conclusion of this test and assess its statistical significance, the p-value is evaluated and compared with the threshold defined for the significance level (5%). For a p-value higher than this threshold, there is no statistical evidence to reject the null hypothesis, indicating that the variables do not have any association between them. For a p-value lower than the threshold, there is statistical evidence to reject the null hypothesis, which means there is statistical evidence of an association between the variables tested.
Ethical Statement
The study was approved by the Ethics Committee of our Hospital, and written informed consent was obtained from all patients (Ethical Approval Number:001/2019F).
Results
A total of 341 patients were included in the study, of whom 88% were women and 56% were older than 55 years. Among the women in the study sample, 56% had a malignant disease, while this percentage increased to 66% in the male patients. Regarding the variable of age, the ROM values were similar between individuals under- and above-55 years of age (58% and 56%, respectively). The age cutoff was based on the American Joint Committee on Cancer Tumour, Node, Metastasis staging system classification(5).
The most prevalent comorbidity was hypertension (46%), followed by dyslipidaemia (23%) and diabetes (15%). Previous radiation exposure was present in 4% of patients, with an ROM of 72%.
The majority of the nodules had sizes ranging from 10-40 mm (71%), followed by nodules larger than 40 mm (9%), with the remainder being smaller than 10 mm.
The surgical procedure was total thyroidectomy in 94% of the patients and lobectomy with isthmectomy in the remaining patients.
FNAC was performed for one nodule in 322 patients and for two nodules in 19 patients (n=360 index nodules). Hereafter, all data are referred to in terms of nodules from a total of 360 nodules.
Regarding histopathological diagnoses, the majority (55%) were diagnosed with malignant tumours, of which the largest proportion was Papillary Thyroid Cancer (PTC) (180/197). In this patient cohort, 43% had a benign diagnosis and 2.1% were borderline (Table 1). The new TBSRTC guidelines were taken into consideration, and the AUS and FN categories were divided into two subcategories: AUS with nuclear atypia vs. AUS-other (architectural atypia, oncocytic atypia, nuclear changes not suggestive of PTC, psammoma bodies, and atypical lymphoid cells) and FN with and without oncocytic features.
In the cytological diagnoses, FN dominated (48%) with the majority being “without oncocytic cells”, followed by AUS (22%) (Table 1).
Malignancy was most common in the malignant category (TBSRTC VI) (97%), followed by the Suspicious for Malignancy category (TBSRTC V) (77%). For AUS (TBSRTC III) and FN (TBSRTC IV), the percentages of malignant tumours were 44% and 43%, respectively (Table 2).
The malignancy rates among unilateral and bilateral nodules were 60% and 67%, respectively. Regarding focality, the ROM was 57% and 69% for unifocal and multifocal nodules, respectively. Adenopathy (without assessment of the ultrasonographic features of each adenopathy) was present in only 7% of the malignant cases; however, when present, 94% were malignant.
Discussion
All patients (TBSRTC categories III, IV, V, and VI) underwent surgical intervention, with the majority undergoing total thyroidectomy. However, 43% of the cases proved to be benign tumours. This raises the question of how surgeons may limit unnecessary surgical interventions while ensuring that no malignant cases are overlooked.
While evaluating a patient and deciding how to manage thyroid nodule disease, multiple factors should be considered, including patient demographics, personal and family histories, and the results of the diagnostic tools available.
Historically, women have been associated with a greater presence of thyroid nodules, and men with higher malignancy rates. Nevertheless, the meta-analysis of autopsy studies for subclinical thyroid cancer conducted by LeClair et al. led to the belief that this is an oversimplification, and that sex disparity is mostly confined to the detection of small subclinical PTCs that are equally common in both sexes in autopsy studies, but are identified much more often in women. According to their findings, as cancer lethality increases, the ratio of detection by sex approaches 1:1. This data trend may be associated with sex differences in healthcare utilisation and may pose a danger for both sexes, with over- and under-detection in women and men, respectively. [6] Other retrospective studies continue to confirm the higher prevalence in women, but with a tendency to fade in the older age groups and with poorer prognoses in men, along with poorer survival and more aggressive disease at presentation. However, no clear reasons have been reported for these disparities.[7,8,9]
Hypertension was the most common comorbidity in patients with thyroid nodules. Although this aligns with the findings reported in the literature, no direct correlation between these two diseases has been demonstrated. [7,10,11] However, previous radiation exposure has been shown to have a positive correlation with the occurrence of thyroid nodules, especially if exposure occurs at an early age, with the most notable studies being the ones focused on survivors of the atomic bomb attacks in Japan and the reactor disaster in Chernobyl [12,13]. Although our present study sample has a limited number of cases of radiation exposure, the ROM was still high in this subgroup (72%).
Several diagnostic instruments guide surgeons in selecting the optimal course of action. The TI-RADS scoring system and some of its variations based on ultrasonographic characteristics indicate the need for FNAC.[14] In this study, this decision was based on the Portuguese Direção Geral de Saúde guidelines. [15]
The cytopathology report, especially if it follows the TBSRTC guidelines, will further guide the course of treatment based on the ROM for each category.
The indeterminate categories (TBSRTC III and IV) remain problematic, without a clear consensus on treatment options. The calculated ROM was observed to be similar between both categories: 44% and 43% for categories III and IV, respectively. These values are considerably higher than those reported in the literature, including the ROM values for malignancies like non-invasive follicular tumour with papillary-like nucleus and well differentiated tumour of uncertain malignant potential. The literature reports a 10-30% ROM for TBSRTC III and 25-40% for TBSRTC IV categories. [3] A possible reason for this disparity is that only nodules that underwent surgery were evaluated, suggesting that other factors could have been considered. For the Suspicious for Malignancy (V) and Malignant (VI) TBSRTC categories, the ROM was in agreement with that reported in the literature. [1,16]
To improve the discriminatory power of the cytopathological classification, the TBSRTC 2023 guidelines (that separate each of the two indeterminate categories into two sub-categories) makes it possible to further scrutinise the risk of malignancy. The TBSRTC category III (ROM 13-30%) is now divided into Atypia of Undetermined Significance with Nuclear Atypia and Other Atypia of Undetermined Significance. The calculated ROM was 55% for AUS nuclear atypia and 43% for AUS other, and this agrees with the original purpose of this subdivision, as it emphasises a relatively higher ROM in the presence of nuclear atypia. Regarding TBSRTC Category IV (23-34%) that is now divided into Follicular Neoplasm with and without oncocytic cells to further align with the 2022 World Health Organization Classification of Thyroid Neoplasms, the calculated ROM was 31% and 53%, respectively. [4]
Most published studies correlate the ultrasonographic features with the cytological results, given their relevance in the scoring systems that guide the decision to perform FNAC. Similarly, we have correlated the individual ultrasonographic characteristics with the cytological results in the present study. The ultrasonographic characteristics that were statistically significant for pre-surgery characterisation in the higher TBSRTC categories were the presence of hypoechoic nodules (p<0.001), microcalcifications (p-0.001), irregular margins (p-0.001) and the presence of adenopathy (p-0.001).
Hypoechogenicity is known to be highly specific for malignancy (92-94%) [18]. Microcalcifications have a specificity for malignancy of 86-95% in the literature[18]. Evaluation of margins also plays an important role in assessing malignancy, with previous studies reporting that spiculated or micro-lobulated margins (92% specificity) and poorly defined margins suggest malignancy[18]. Only the regularity of the margins was evaluated, and irregular margins were associated with a higher TBSRTC classification score. In future, a further division into regular, spiculated, and ill-defined margins may enhance nodule description and provide information about the ROM.
The presence of adenopathy is also associated with malignancy; thus, ultrasonographic examination of cervical lymph nodules and reporting their location and characteristics are essential for all ultrasonographic thyroid evaluations.
Although not helpful, the size of the nodule should be monitored over time, because malignant nodules usually grow more quickly. [19,20] The progression of nodule growth was also studied.
Characteristics such as a taller-than-wide shape and the halo sign, although usually associated with an increased ROM [21,22], showed no statistical significance in this study. The significance of central vascularity was not assessed because it was not reported in the ultrasonographic results for the majority of this patient cohort.
To further test the possible role of ultrasonographic features as a deciding factor between surgery and surveillance, they were correlated with the final histopathological results. In this analysis, only the presence of microcalcifications and adenopathies were observed to be significantly associated with a higher ROM. These results agree with a systematic review conducted by Remonti et al., where only the presence of microcalcifications was significantly correlated with the histopathological diagnosis of indeterminate cytology nodules. [23] The assessment of microcalcifications can be particularly challenging because they are often similar to colloids. Considering its importance, it is essential that professionals performing ultrasonography are highly trained and that they correctly document the presence of microcalcifications and/or colloids.
According to the American Thyroid Association guidelines, a comprehensive cervical lymph node survey is advisable for all thyroid cancer cases, and a preoperative map highlighting possible adenopathies should be prepared [16].
The present study highlights the essential role that ultrasonography can play, not only when deciding the diagnostic approach, but also when managing treatment options, and this is especially important in the TBSRTC indeterminate categories.
Regarding the limitations of this study, this was a retrospective study that excluded patients in the Non-Diagnostic and Benign TBSRTC categories (TBSRTC categories I and II) as well as all those patients who were not subjected to thyroidectomy. This sampling strategy precluded the calculation of other parameters, such as specificity and predictive values. Regarding the relative prevalence of each TBSRTC category in our study sample, there was an increase in the prevalence of the remaining categories because of the exclusions mentioned above. In a normal setting, to ensure the reliability of the cytological results, TBSRTC III should account for no more than 10% of all specimens, whereas it amounts to 22% of the present study sample.[16] Although not evaluated, family history should not be overlooked, as it is extremely important in malignant disease diagnoses. Finally, no international grading system, such as the TI-RADS system, was used.
Ultrasonographic characteristics should be reported in a standardised manner to ensure that every relevant parameter is evaluated, easily understandable, and useful in the decision-making process. This would decrease inter-operator variability in the data, facilitate surveillance strategies, be helpful for research purposes, and simplify the processing and sharing of data.
Moving forward, other diagnostic tools such as molecular and genetic tests should be considered to help evaluate the ROM and prevent unnecessary surgical interventions[24,25]. Elastosonography also has an important role to play and should be employed and evaluated, with “stiffness” or hard consistency being reported to have a sensitivity for malignancy of up to 97%. [18,23]
When deciding on the best clinical and surgical approach for thyroid nodules, patient demographics, symptoms, comorbidities, personal and family histories, and the results of ultrasonography, cytopathology, thyroid function, and molecular/genetic tests should be considered to provide the best possible care.
This study contributes data for evaluation of the new TBSRTC guidelines as well as ultrasonographic factors that can influence the ROM.
Conclusion
Selecting the best intervention strategy for indeterminate-category thyroid nodules remains challenging, even after the release of the updated 2023 TBSRTC classification. Therefore, clinicians and surgeons must rely on other factors to make evidence-based decisions. This study supports the importance of identifying the presence of microcalcifications and adenopathy as significant features associated with an increased ROM, highlighting the association between these ultrasonographic characteristics and the histopathological diagnosis of malignancy.
Ethical Approval:
The study was planned as exempt by the ethics committee and conforms to the standards of the Helsinki Accord. This study was developed in Centro Hospitalar de Setúbal, E.P.E. and National School of Public Health – Universidade Nova de Lisboa, being included in the 8th Edition of the Doctoral Program in Public Health. Prof. Dra. Isabel Loureiro (ENSP-UNL) will be responsible for thesis orientation. Complementarily, the author will have as supervisor Dr.a Rosário Eusébio (Serviço de Cirurgia Geral, Centro Hospitalar de Setúbal, E.P.E.)
Conflicts of interest:
The authors declare that there are no conflicts of interest.
Financial Support:
The authors have no funding to report.
Abbreviations
Histopathological diagnoses of nodules:
Benign;
Borderline:
Malignant:
Cytological categorization of nodules according to Bethesda:
| - CLT | Chronic lymphocytic thyroiditis |
| - BFN | Benign follicular nodule |
| - FA | Follicular adenoma |
| - PA | Papillary adenoma |
| - HCA | Hürthle cell adenoma (Oncocytic adenoma is preferred term) |
| - NIFT-P | Non-invasive follicular tumour with papillary nucleus |
| - WDT-UMP | Well differentiated tumour of uncertain malignant potential |
| - PTC | Papillary thyroid carcinoma |
| - Sub-cm | Subcentimeter Papillary thyroid carcinoma |
| - FTC | Follicular thyroid carcinoma |
| - MTC | Medullary thyroid carcinoma |
| - HCC | Hürthle cell carcinoma (Oncocytic carcinoma is preferred term) |
| ND | Non-diagnostic (Category 1) |
| B | Benign (Category 2) |
| AUS | Atypia of undetermined significance (Category 3) |
| FN/SFN | Follicular neoplasm or Suspicious for follicular neoplasm (Category 4) |
| SM | Suspicious for malignancy (Category 5) |
| M | Malignant (Category 6) |
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Table 1.
Number of histopathological and cytological diagnoses.
| Characteristics | n | % (n/360) | |
|---|---|---|---|
|
Histopathological diagnoses |
Benign histology/tumours Borderline tumours NIFTP WDT-UMP Malignant tumours miPTC** PTC FTC MTC HCC** |
155 8 6 2 197 10 180 2 1 4 |
43 2 2 1 55 3 50 1 0 1 |
|
Cytological diagnoses |
AUS* AUS-nuclear atypia AUS-other FN* FN without oncocytic cells FN with oncocytic cells SM M |
79 (11) (68) 173 (95) (78) 44 64 |
22 (3) (19) 48 (26) (22) 12 18 |
NIFT-P, non-invasive follicular tumour with papillary-like nucleus; WDT-UMP, well differentiated tumour of uncertain malignant potential; miPTC, papillary thyroid microcarcinoma; PTC, papillary thyroid carcinoma; FTC, follicular thyroid carcinoma; MTC, medullary thyroid carcinoma; HCC, hürthle cell carcinoma; AUS, atypia of undetermined significance; FN, follicular neoplasm; SM, suspicious for malignancy; M, malignant. *According to the 3rd TBSRTC guidelines, the AUS and FN categories are each split into two subcategories. The number of nodules in these subcategories are given in parentheses. ** Since the 2022 WHO Classification of Thyroid Neoplasms [5], these histopathological terms are no longer in use. However, for the purpose of this article, they are retained.
Table 2.
Histopathological results following FNAC diagnoses.
| Benign histology | Malignant (or borderline) histology | Total number | Risk of malignancy* (%) | |
|---|---|---|---|---|
|
AUS AUS-nuclear atypia AUS-other |
44 (5) (39) |
35 (6) (29) |
79 (11) (68) |
44 (55) (43) |
|
FN FN without oncocytic cells FN – with oncocytic cells |
99 (45) (54) |
74 (50) (24) |
173 (95) (78) |
43 (53) (31) |
| SM | 10 | 34 | 44 | 77 |
| M | 2 | 62 | 64 | 97 |
AUS, atypia of undetermined significance; FN, follicular neoplasm; SM, suspicious for malignancy; M, malignant; NIFT-P, non-invasive follicular tumour with papillary-like nucleus; WDT-UMP, well differentiated tumour of uncertain malignant potential; * The risk of malignancy (ROM) was calculated, including borderline (WDT-UMP and NIFT-P) tumours.
Table 3.
Crosstabulation tables between ultrasonographic characteristics and cytopathological classification.
Table 3.
Crosstabulation tables between ultrasonographic characteristics and cytopathological classification.
| Ultrasonographic characteristics: | AUS n (%) |
SFN n (%) |
SM n (%) |
M n (%) |
p-value (for Pearson Chi-Square Independence test) |
|---|---|---|---|---|---|
|
Echogenicity Cystic Hypoechoic Isoechoic Hyperechoic |
- 16 (21.9) 55 (75.3) 2 (2.7) |
2 (1.4) 49 (33.8) 94 (64.8) - |
- 14 (35) 26 (65) - |
2 (3.8) 32 (61.5) 18 (34.6) - |
<0.001 |
|
Calcification No calcification Macrocalcification Microcalcification |
52 (75.4) 8 (11.6) 9 (13) |
105(73.9) 14 (9.9) 23 (16.2) |
27 (73) 7 (18.9) 3 (8.1) |
19 (39.6) 13 (27.1) 16 (33.3) |
<0.001 |
|
Margins Regular Irregular |
54 (79.4) 14 (20.6) |
114(80.9) 27 (19.1) |
29 (74,4) 10 (25.6) |
23 (52.3) 21 (47.7) |
0.001 |
|
Shape Wider-than-tall Taller-than-wide |
68 (94.4) 4 (5.6) |
137(91.3) 13 (8.7) |
34 (87.2) 5 (12.8) |
42 (79.2) 11 (20.8) |
0.036 |
|
Halo No halo Complete hypoechoic Incomplete hypoechoic Hyperechoic |
36 (49.3) 33 (45.2) 3 (4.1) 1 (1.4) |
88 (57.9) 56 (36.8) 7 (4.6) 1 (0.7) |
29 (69) 11 (26.2) 2 (4.8) - |
41 (69.5) 12 (20.3) 4 (6.8) 2 (3.4) |
0.135 |
|
Adenopathy Absent Present |
77 (97.5) 2 (2.5) |
169(97.7) 4 (2.3) |
43 (97.7) 1 (2.3) |
55 (85.9) 9 (14.1) |
0.001 |
| TOTAL | 65 | 135 | 36 | 38 |
AUS, atypia of undetermined significance; FN/SFN, follicular neoplasm/suspicion of follicular neoplasm; SM, suspicious for malignancy; M, malignant. A total of 274 nodules have the following radiological features: Echogenicity, calcification, halo, irregular shape, margins, and adenopathy. Vascularization is excluded because of the high number of “not applicable (N/A)” cases, and a very high p-value.
Table 4.
Crosstabulation tables between ultrasonographic findings and histological characteristics (malignant includes low risk tumours).
Table 4.
Crosstabulation tables between ultrasonographic findings and histological characteristics (malignant includes low risk tumours).
| Ultrasonographic characteristics: | Benign n (%) |
Malignant n (%) |
p-value ( for Pearson Chi-Square Independence test) |
|---|---|---|---|
|
Echogenicity Cystic Hypoechoic Isoechoic Hyperechoic |
1 (0.7) 40 (28.8) 97 (69.8) 1 (0.7) |
3 (1.8) 71 (41.5) 96 (56.1) 1 (0.6) |
0.093 |
|
Calcification No calcification Macrocalcification Microcalcification |
112 (81.2) 13 (9.4) 13 (9.4) |
91 (57.6) 29 (18.4) 38 (24.1) |
<0.001 |
|
Margins Regular Irregular |
109 (80.7) 26 (19.3) |
111 (70.7) 46 (29.3) |
0.047 |
|
Shape Wider-than-tall Taller-than-wide |
135 (94.4) 8 (5.6) |
146 (85.4) 25 (14.6) |
0.009 |
|
Halo No halo Complete hypoechoic Incomplete hypoechoic Hyperechoic |
82 (56.2) 57 (39) 7 (4.8) - |
112 (62.2) 55 (30.6) 9 (5) 4 (2.2) |
0.142 |
|
Adenopathies Absent Present |
154 (99.4) 1 (0.6) |
190 (92.7) 15 (7.3) |
0.002 |
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