Managing the thyroid nodule

Transcription

1 Managing the thyroid nodule Poster No.: C-1714 Congress: ECR 2013 Type: Educational Exhibit Authors: J. C. Rayón-Aledo, I. Zabala Martín-Gil, C. Laganâ, S Llorente, M. L. Parra Gordo, D. Terriza Rueda ; Madrid/ES, 2 Valencia/ES Keywords: Neoplasia, Hyperplasia / Hypertrophy, Endocrine disorders, Puncture, Ultrasound-Colour Doppler, Ultrasound, Thyroid / Parathyroids, Head and neck, Anatomy DOI: /ecr2013/C-1714 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 65

2 Learning objectives Nodular thyroid disease may be manifested by a clinical palpation of a nodule, growth of the gland and / or alteration of thyroid hormones. However it is common the incidental presentation in asymptomatic patients while performing imaging tests for any other reason. Throughout this poster we will propose a management algorithm of the thyroid nodule and its justification, emphasizing the following sections: The anatomy of the thyroid. Pathology: divided according to their distribution (nodular or diffuse). The radiological management of thyroid nodules. Ultrasound and characterization of nodular pathology. The technique and significance of the results obtained by FNA of these lesions. Proposals for the future management of thyroid nodules in the medium term: new classifications and algorithms. Images for this section: Page 2 of 65

3 Fig. 1: Several images of thyroid nodules with different sonographic features. Page 3 of 65

4 Background MANAGING THE THYROID NODULE Fig. 1: Several images of thyroid nodules with different sonographic features. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES 1. ANATOMY AND HISTOLOGY: Page 4 of 65

5 The thyroid is a unique gland which morphology is similar to an H. It is located in the anterior aspect of the neck and rests on the anterior laryngotracheal canal. Fig. 2: Drawing a thyroid gland References: Irene Zabala Martin. H. U. La Princesa. Madrid. Spain. We can differenciate a middle and narrow portion called isthmus and two bulkier lateral lobes. The lateral lobes have a triangular shape, similar to a pyramid. They are highly variable in measure (rump length of mm and a anteroposterior diameter of mm). The inner face hugs the trachea. The outer surface is covered by muscle planes (sternothyroid, sternocleidhyoid, omohyoid and sternocleidomastoid), the superficial cervical fascia and skin. The back side is next to the neurovascular bundle (there are direct relationships to consider to common carotid artery and internal jugular vein). The thyroid has a capsule surrounding parenchyma consisting of a set of thyroid follicles. The capsule is hyperecoic and delimits the lobes. The parenchymal echogenicity is medium-high. In childhood and youth is usually homogeneous, with the pass of time it Page 5 of 65

6 atrophies and its appearance becomes more heterogeneous with frequent nodules. ( Fig. 3 on page 15 ) Fig. 3: Normal thyroid visualization in ultrasound in a transverse visualization. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES 2. THYROID DISEASE: Structural disorders of the thyroid may be accompanied or not by function disorders. Conversely, there are also changes in the function that can produce alterations in morphology. From a radiological point of view, divide in thyroid disorders: diffuse nodular Diffuse disorders: Simple diffuse hyperplasia or Goiter ( Fig. 4 on page 16 ): Page 6 of 65

7 - More common in young women. - Related to problems in the synthesis of thyroid hormones. It may be a normo or hyperfunctioning multinodular hyperplasia. Immune evolutionary chronic thyroiditis: - Young Women. - It is due to an autoimmune disorder that causes thyroiditis, silent or painless, with hyperplasia and lymphocytic infiltration, due to the presence of antithyroid antibodies. - Can evolve to: Hyperplastic or Hashimoto's thyroiditis (heterogeneous echotexture with fibrous bands, which can produce a multilobulated or micronodular appearance, sometimes with nodules). In early stages, is hypervascularized. Can evolve to lymphoma, leukemia or papillary thyroid tumour. Fibrous or Riedel's thyroiditis (atrophic appearance with hyperechoic bands in the parenchyma). Viral thyroiditis, De Quervain's thyroiditis ( Fig. 5 on page 16 ): - Young women between 15 and 30 years. - Transient. - Sharp pain in the thyroid, fever and increased ESR. - Normal echogenicity. Page 7 of 65

8 Fig. 5: De Quervain's thyroiditis. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES Acute or infectious thyroiditis: - Bacterial infection by hematogenous spread or contiguity to an infected structure (thyroglossal cyst..). -Symptoms range from thyroid pain to systemic disease. Nodular Disorders: They are common findings, being found in up to 50% of women over 50 years old. Most are clinically silent. Only 5-10% of these nodules are malignant. Between them most are papillary type, with good prognosis because of their slow growth and low mortality. In children, the percentage of malignancy is about 30%. The lower the age the more aggressive they are, with high percentages of multicentricity, cervical lymphadenopathy and lung metastases. BENINGN MALIGNANT Page 8 of 65

9 Focal Nodular Hyperplasia, adenomatous Papillary Carcinoma or colloid Benign Follicular Adenoma Papilo-follicular Carcinoma Cyst (simple, colloid or bleeding) Follicular Carcinoma, Medulary Carcinoma, Anaplastic Carcinoma Hashimoto's thyroiditis Lymphoma Metastases (Lung, Breast and Kidney) Most Frequent Nodular Disorders Hyperplastic adenomatous or colloid nodules ( Fig. 6 on page 17, Fig. 7 on page and Fig. 8 on page ): - They are the most frequent. May be multiple. - Ultrasonographically they are lesions that share characteristics: they are mostly solid, homogeneous and well defined. - May be hyper, iso or hypoechoic, with bright foci. We can observe the image feature "comet tail", which indicates the existence of a colloid component crystallized therein. When colloid spaces are large, a "spongiform" pattern is identified. - They usually have a cystic component, sometimes with septations or mural nodule, which increases as the size of the nodule does. - They may present an hypoechoic halo wich is related to the presence of nearby surrounding vasculature. Page 9 of 65

10 Fig. 8: Hyperplastic nodule with colloid component. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES Benign follicular adenomas ( Fig. 9 on page 17 ): - They comprehend 5-10% of thyroid nodules. More common in women. - Characterized by compressing adjacent tissue and being surrounded by a fibrous capsule. - Solid, normo, hypo or hyperechoic, well defined and with an hypoechoic halo. - You can only distinguish from follicular carcinoma because of capsular and vascular invasion, therefore they are not differentiable by ultrasound or FNA. You can only differentiate definitively after resection of the nodule. Page 10 of 65

11 Fig. 9: Follicular Adenoma. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES Cysts ( Fig. 10 on page 18 ): - They come from complete degeneration of hyperplastic nodules, by necrosis or bleeding. - Are anechoic or present low echogenicity representing colloid, serous or hemorrhagic material. Hashimoto's thyroiditis: - (See diffuse disorders) may be accompanied by nodules. Papillary carcinoma ( Fig. 11 on page 20 ): - Accounts for 75% of malignant thyroid lesions. Women under 40 years. Survival is 90% after 20 years. - Lymphatic spread is more common. The presence of metastatic lymph nodes at diagnosis does not affect the good prognosis. - It is commonly multifocal and slow growing. Usually contain follicular elements, in this case being referred as mixed or papillary / follicular. - Ultrasonographycally is hypoechogenic and totally solid. One can find microcalcifications (psammoma bodies) which are calcium salt deposits and should not be confused with colloid clusters, typical in hyperplastic nodules. Page 11 of 65

12 The affected lymph nodes may contain microcalcifications or cystic degeneration. Follicular Carcinoma ( Fig. 12 on page 20 ): - Accounts for 10% of thyroid neoplasms. More common in women in the sixth decade of life. They have a 75% survival at 20 years. - Spreads through the blood (bone metastases, brain, lung and liver). Lymph node implication is rare. - Usually coexist with multinodular goiter. - The morphology is similar to follicular adenoma and diagnosis is compulsorily made by biopsy of specimen. Medullary carcinoma ( Fig. 13 on page 21 ): - Accounts for 5% of thyroid cancers. More common in elderly. Its behavior is more aggressive and 42 to 90% die within five years. - 15% are part of a multiple endocrine neoplasia (MEN type IIA). Derived from calcitonine secreting parafollicular cells. - Microcalcifications can be seen both in the primary tumor and in metastatic lymphadenopathy. Anaplastic Carcinoma ( Fig. 14 on page 22 ): - Accounts for 5% of thyroid neoplasms. Affects elderly patients. The prognosis is dismal. - There is extrathyroidal local invasion and thyroid shows an hypoechoic invasive mass appearance. Page 12 of 65

13 Fig. 14: Anaplastic Thyroid Carcinoma with local invasion. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES Thyroid lymphoma ( Fig. 15 on page 23 ): - 5% of thyroid neoplasms. More common in older women. - Can evolve from Hashimoto's thyroiditis. - They are usually non-hodgkin lymphomas. - It is a rapidly growing mass, solid, hypoechoic wich infiltrates the rest of the parenchyma. Metastases: - Typically lung, breast and kidney. - Sonographic features are unspecific. - They are usually identified as solid nodules when a primary neoplasm is already known. Summary of nodular thyroid disease ( Table 1 on page 19 ). Page 13 of 65

14 Table 1: Summary of tumoral thyroid pathology. References: Jose Carlos Rayón-Aledo. H. U. La Princesa. Madrid. Hoang more graphically summarize thyroid disorders in Fig. 16 on page 18 published in RadioGraphics. (Hoang JK, et al. "U.S. Features of thyroid malignancy: pearls and pitfalls". RadioGraphics 2007, 27: ). Images for this section: Page 14 of 65

15 Fig. 2: Drawing a thyroid gland Page 15 of 65

16 Fig. 3: Normal thyroid visualization in ultrasound in a transverse visualization. Fig. 4: Bilateral increase in size of the thyroid lobes in a case of diffuse hyperplasia. Page 16 of 65

17 Fig. 5: De Quervain's thyroiditis. Fig. 6: Hyperplastic nodule. Page 17 of 65

18 Fig. 9: Follicular Adenoma. Fig. 10: Simple Cyst. Page 18 of 65

19 Fig. 16: Prevalence of thyroid tumors by Hoang et al. in Radiographics Table 1: Summary of tumoral thyroid pathology. Page 19 of 65

20 Fig. 11: Thyroid Papillary Carcinoma. Page 20 of 65

21 Fig. 12: Follicular Carcinoma. Page 21 of 65

22 Fig. 13: Medular Thyroid Carcinoma. Page 22 of 65

23 Fig. 14: Anaplastic Thyroid Carcinoma with local invasion. Fig. 15: Thyroid Lymphoma. Page 23 of 65

24 Imaging findings OR Procedure details MANAGING THE THYROID NODULE II Table 2: Algorithm for the management of thyroid nodule. References: Irene Zabala Martin. H. U. La Princesa. Madrid. Spain. 3. RADIOLOGICAL MANAGMENT OF THYROID NODULE. Clinical assessment should aim to discover risk factors for thyroid cancer (Table 3 on page 40) which are essential, together with radiological findings, to decide the handling of each case. Page 24 of 65

25 Table 3: Clinical risk factors for malignancy in patients with thyroid nodules. Courtesy of Cortazar et al. Radiología References: R. Cortázar García, R. Quirós López y M.M. Acebal Blanco. "Papel del radiólogo en el manejo del nódulo tiroideo". Radiología. 2008;50: Often, those are insufficient indicators making it necessary to perform additional tests: blood hormone levels / interventional procedures such as FNA. Assessment of thyroid function: By determining the serum thyroid stimulating hormone (TSH). Generally, aggressive lesions have a normal function, and less frequently hyperfunction. In medullary carcinoma the more determinant of malignancy analytical parameter is the calcitonin serum level. Imaging tests: # Scintigraphy: Rate function with a radioisotope (I 131). Nodules can be hot or cold: Hot: increased uptake of radiotracer respect the rest of the parenchyma, they represent 10% of thyroid nodules. They are almost always benign ( Fig. 17 on page 40 ) Cold: decreased or no uptake compared to the rest of the parenchyma. They account for 90%. Page 25 of 65

26 Fig. 17: 99Tc-pertechnetate scintigraphy of hyperfunctioning right thyroid nodule. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES # Ultrasound: It is the basic tool for radiological diagnosis of nodular thyroid disease and has several advantages over other techniques: Detects nodules up to 3 mm and characterize them, enabling the identification of some findings that are associated with high suspicion of malignancy. Diagnoses the existence of lymphadenopaties. Serves as image guide for diagnostic interventional (FNA and core biopsy) and therapeutic procedures (cyst aspiration, ethanol injection and laser thermal ablation). # Other imaging tests. CT, MRI and PET are not commonly used tests in routinary evaluation of the thyroid nodule. Computerized tomography (CT) and magnetic resonance imaging (MRI) are used to delineate the extent of intrathoracic goiter and its relationship to mediastinal structures, but do not rule out malignancy. Positron emission tomography (PET) with 18-fluorodeoxyglucose evaluates glucose metabolism. It can help differentiate benign from malignant nodules. Page 26 of 65

27 4. ULTRASOUND AND CHARACTERIZATION OF NODULES. - It uses a high-frequency linear transducer (7.5 to 15 MHz). - Patient leans supine with the neck extended. - Explores the longitudinal and transverse plane and lower poles asking the patient to swallow. - You should assess the carotid arteries, the internal jugular veins and submandibular and supraclavicular lymph nodes, if any. * What to report: - The symmetry and size of the lobes. - The thyroid parenchymal echogenicity. - Focal nodular lesions. - The local invasion and lymph node if any. - The vascularity of the gland and lymphs using Doppler mode ultrasonography. There are no absolut reliable sonographic criteria to differenciate a benign nodule from a malignant one, but using the US we can obtain relevant data suggesting either possibility. Page 27 of 65

28 Fig. 18: Summary of basic ultrasound findings to be considered in the study of thyroid nodule. References: Irene Zabala Martin. H. U. La Princesa. Madrid. Spain. 1. Size and the number of nodes: # Nodule size is not useful in predicting malignancy thereof. Several studies have evaluated the sonographic features of malignant and benign tumors in nodules larger or smaller than 1 cm and it has been concluded that size does not matter ( Fig. 19 on page 41 ). The sonographic features for benignity or malignancy described below are more sensitive and specific in the larger lesions. Also, the smaller malignant nodules have a more favorable prognosis than the larger overall. Fig. 19: Papillary Carcinoma smaller than 1 cm in diameter. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES Page 28 of 65

29 # The risk of malignancy in the multinodular disease equals to the solitary nodule, so puncture should be performed guided by their morphological characteristics, not by their size. When the number of suspicious nodules increases, also increases the risk of malignancy ( Fig. 20 on page 41, Fig. 21 on page 42 ). 2. Form and margins: # Taller than wide: Larger in the anteroposterior (AP) plane than in transverse is highly specific (93%) of malignancy. It does reflect a growth over normal glandular tissue planes ( Fig. 22 on page 43 ) # Uniform and complete halo: Highly suggestive of benignity, with a specificity of up to 95%. Corresponds to pseudocapsule of fibrous connective tissue, compression of parenchyma and chronic inflammatory infiltrate. ( Fig. 23 on page 44 ). # Spiculated or irregular edges: A nodule poorly defined and with irregular margins suggests infiltration of adjacent parenchyma. A thyroid nodule is considered ill-defined when more than 50% of its border is not clearly defined. ( Fig. 24 on page 44 y Fig. 25 on page 45 ). Fig. 24: This nodule exhibits spiculated edges. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES Page 29 of 65

30 3. Echogenicity: # Most thyroid carcinomas are solid and hypoechoic, especially papillary carcinoma. ( Fig. 26 on page 46, Fig. 27 on page 47 y Fig. 28 on page 47 ). # A marked hypoechoic parameter is very suggestive of malignancy, with specificity of 94% ( Fig. 28 on page 47 ). Fig. 28: Strong hypoechogenicity. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES 4. Cystic component: # Completely cystic nodules are benign in nature. Only 2.5% of carcinomas show more than 50% of cystic component. Careful examination will show vascularized intracystic solid components on those cases. We must also take into account the possible existence of the papillary variant of cystic carcinoma ( Fig. 29 on page 48 y Fig. 30 on page 48 ). In metastatic lymph nodes it is more common to find cystic changes (Fig. 31 on page 49). Page 30 of 65

31 Fig. 31: Suspicious lymphadenopathy, cystic component and microcalcifications are shown. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES # Honeycomb pattern (spongiform): There are multiple microcystic spaces (> 50% node) bordered by numerous thin septa. Cytology is usually benign ( Fig. 32 on page 49 ). 5. Calcifications: # Microcalcifications: - Punctate echogenic foci without acoustic shadowing, 1mm size. - Often correspond to psammoma bodies (basophilic calcium deposits with laminar aspect of microns size). - Increase by three the risk that the solid nodule is malignant ( Fig. 33 on page 50 ). # Macrocalcifications: - Over 1mm, with acoustic shadowing, typically in areas of fibrosis and / or necrotic degeneration. - Increase by two the risk of malignancy of the solid nodule. -Coarse central calcifications or calcified amyloid: Appear in medullar carcinoma and may be present in long evolution multinodular goiter ( Fig. 34 on page 50 ). Page 31 of 65

32 Fig. 34: Coarse calcifications within thyroid nodule with acoustic shadowing. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES # Eggshell calcifications: - Peripheral calcification around a nodule. Initially seen as a sign of kindness, but currently there are controversies. It is believed to be a sign of malignancy when there is a disruption of peripheral calcification. # Dense and thick colloid consolidations produce punctate echogenic foci that should not be confused with microcalcifications (it shows a posterior reverberation artifact known as comet tail) as in Fig. 35 on page Vascularization: # The most common pattern in malignant lesions is marked central hypervascularity. Appears in 69-74% of papillary carcinomas, although it is not an specific sign ( Fig. 36 on page ). # Perinodular vascularization: more tipically in benign nodules, appears in 22% of malignant nodules ( Fig. 37 on page ). A completely avascular nodule is very unlikely to be malignant. 7. Lymph nodes: In addition to the features of the thyroid nodules, it is very important to assess the regional cervical lymphadenopathy. - There are nodal metastases in 19.4% of thyroid tumors at diagnosis. - Examination of the internal jugular chain of lymph nodes in the neck should be part of a routine study (Fig. 38 on page 51, Fig. 39 on page 52 y Fig. 40 on page 52). Malignant characteristics are as follows: Rounded and / or large. No central echogenic fatty hilum. Heterogeneous echogenicity. Page 32 of 65

33 Cystic changes (papillary carcinoma). Calcifications (papillary / medullar). Kwak et al. summarize in this table Table 4 on page 53 the findings of their study referring to the correlation observed between some ultrasound findings and the malignancy of the nodules. Table 4: Relation between ultrasonographic characteristics and malignancy probability according to Kwak et al. Radiology References: Kwak et al. "Thyroid imaging Reporting and data System for US Features of Nodules, A Step in Establisihing Better Stratification of Cancer RisK". Radiology. 2011; 260: FINE NEEDLE ASPIRATION (FNA) IN DIAGNOSTIC MANAGEMENT: The FNA of thyroid with ultrasound guidance is the test of choice for the characterization of thyroid nodules. Thanks to it, the number of surgeries performed on the thyroid has dramatically decreased. This procedure is minimally invasive, safe and inexpensive. Even when the nodule is palpable (greater than 1 cm), when the puncture is performed under ultrasound guidance better results, with a lower "non diagnostic" rate, will be obtained. Technique: Page 33 of 65

34 - Before performing the procedure it has to be explained to the patient and written informed consent must be obtained. - Patient has to be warned not to swallow or make sudden movements when the needle touches the skin to avoid puncture of non target areas. - The patient is placed supine with the neck hyperextended ( Fig. 41 on page 53 ). Fig. 41: Ultrasound guided FNA of a thyroid nodule. References: Irene Zabala Martin. H. U. La Princesa. Madrid. Spain. - A G gauge needle is used, attached to a syringe of 20 cc, which is coupled to a suction gun ( Fig. 42 on page 54 ). - Using the ultrasound, a path that allows a comfortable puncture avoiding to cross the blood vessels is chosen. An approach with a slight inclination of the needle produces greater refraction and better visualization of it (Fig. 43 on page 55). Page 34 of 65

35 Fig. 43: Ultrasonographic picture of a nodule during FNA. The orange arrow signals the point of the needle. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES - When it is appreciated that the tip is fully within the nodule, 1-2 ml are aspirated. - At least two punctures are performed on each node. If you are collecting data from more than one node you must change the needle and syringe. Cytopathologic evaluation: - The samples are evaluated on the go by a pathologist who indicates whether sufficient material for diagnosis has been obtained or the puncture should be repeated. A satisfactory sample must contain at least 6 strips of well-preserved cells with a minimum of cells per strip, lying two aspirates obtained from the same node on two different crystals. - There are circumstances that increase the likelihood of insufficient samples for diagnosis, as a inaccessible or very small (less than 1 cm) nodule. - The interpretation of FNA cytopathologic can be: Non diagnostic (15%): incorrect fixation, hemorrhagic necrotic material... Diagnostic : Benign Malignant Page 35 of 65

36 Indeterminate: 15% -30% of FNA specimens, it is difficult for cytopathologists determine whether the tumor is benign or malignant lesions origin primarily follicular or papillary tumors that do not meet all the criteria of malignancy cytopathology. Some practical advice. # What nodule to choose if more than one? You must select the node on which to puncture according to the sonographic features of malignancy not because of its size. Each individual node is equally likely to be malignant. ( Fig. 44 on page 55 ). Fig. 44: Multiple nodules with multiples sizes and characteristics. References: Radiodiagnóstico, H. U. La Princesa - Madrid/ES # Micronodules (less than 1 cm) or nodules discovered incidentally (usually less than 1 cm). Their inherent risk of developing cancer is the same as on the ones bigger than 1 cm, although it is not clear whether to puncture or not for several reasons: Page 36 of 65

37 a) the puncture may be difficult, increasing the rate of false negatives. b) it has low cost-benefit and risk-benefit rates. c) it is not clear if their diagnosis and removal would increase the life expectancy of the patient (slow growth and good prognosis) ( Fig. 45 on page 56 ). # When should we repeat FNA? - Pathology result is "nondiagnostic". - Discordance between ultrasound and cytological findings. - Growth of the lesion. - Recurrent cyst. # Ultrasound monitoring is recommended for 6-18 months all benign thyroid nodules after initial FNA. If the nodule size is stable (ie no more than a 50% change in volume, or less than 20% increase, in at least two dimensions in solid nodules or in the solid portion of mixed solidcystic nodules) monitoring interval may be longer, around 3-5 years. 6. NEW CONTRIBUTIONS TO THYROID NODULE MANAGEMENT. Due to the high prevalence of benign thyroid nodules, there are attempts to improve management with a new standardized ultrasound classification as to optimize subsequent actions arising from ultrasound (FNA, surgery, monitoring...). Recently, three studies have suggested standardized systems to report thyroid lesions stratifying the risk of malignancy in nodules. The authors used a classification system based on the sonographic features of nodules, quantifying the risk of malignancy for each feature. These classification systems are based on the "Report of breast imaging and Data System" (BI-RADS), which was developed by the American College of Radiology. The BI-RADS is designed to help standardize the reporting of breast imaging and the management of lesions, which promotes communication between physicians and radiologists. The terminology TIRADS was first used by Horvath et al. who describe 10 patterns in ultrasound of thyroid nodules and malignancy rate according to each pattern (Horvath E, Majlis S, Rossi R, et al. "An ultrasonogram reporting system for thyroid nodules stratifying cancer risk for clinical management". J Clin Endocrinol Metab 2009, 94: ). TIRADS 1 Normal thyroid gland TIRADS 2 Benign nodule (0% of malignancy) TIRADS 3 Probably benign nodule (<5% malignancy) TIRADS 4 Suspicious nodule malignancy (5-80% malignancy) Page 37 of 65

38 TIRADS 5 Probably malignant nodule(> 80% malignancy) TIRADS 6 TIRADS CLASSIFICATION Malignant nodule biopsy However, these patterns were not applicable to all nodes as they were designed for those showing very standardized characteristics. Therefore, they were not easily applicable in clinical practice. Shortly thereafter, Park et al. proposed an equation to predict the likelihood of malignancy based on twelve ultrasound image characteristics, although this study has not been recognized in clinical practice. The latest study that has linked these classifications and provided a more refined new one has been carried by Kawk et al. It is similar classification system, but is based on equated probability and the risk of malignancy of each one of the sonographic features evaluated, which are: composition, marked hypoechogenicity, microlobulation, irregular margins, microcalcifications and taller than wide morphology. They are considered independent sonographic features suggesting malignancy (Table 5 on page 57). Page 38 of 65

39 Table 5: Comparison between different pathologic nodules classification systems. Radiology 2011 References: Kwak et al. "Thyroid imaging Reporting and data System for US Features of Nodules, A Step in Establisihing Better Stratification of Cancer RisK". Radiology. 2011; 260: This classification can be easily applied in clinical practice because it is not difficult to count the number of suspicious sonographic features. However, there are several limitations of the study in terms of selection bias, application to other institutions, it does considers that all the features of malignancy have the same equate probability, and so on. The risk of malignancy in each category of this "TIRADS" refers to the BI-RADS categories. However, the clinical aggressiveness and prevalence of nodules of breast and thyroid cancers are definitely different. So, further studies are needed to reach definitive conclusions. To summarize, a path for standardized stratification of overall risk of malignancy of a nodule, according to the number of suspicious sonographic features, that would allow a Page 39 of 65

40 practical and convenient "TIRADS" staging for a better selection of nodules to undergo FNA or avoid unnecessary procedures, is opened. It is also necessary to unify the language and codes among radiologists, pathologists and endocrinologists. Thus, there will be an improvement in both patient management and in a more cost-effective follow-up. Images for this section: Table 3: Clinical risk factors for malignancy in patients with thyroid nodules. Courtesy of Cortazar et al. Radiología Page 40 of 65

41 Fig. 17: 99Tc-pertechnetate scintigraphy of hyperfunctioning right thyroid nodule. Fig. 19: Papillary Carcinoma smaller than 1 cm in diameter. Page 41 of 65

42 Fig. 20: Multinodular Goiter. Page 42 of 65

43 Fig. 21: Multiple nodular lesions with cystic component. Page 43 of 65

44 Fig. 22: This nodule is taller than wider, suspicious for malignancy. Fig. 23: Hypoechoic peripheral halo. Page 44 of 65

45 Fig. 24: This nodule exhibits spiculated edges. Page 45 of 65

46 Fig. 25: Nodule with irregular margins. Page 46 of 65

47 Fig. 26: Solid hypoechoic nodule. Fig. 27: Hypoechoic thyroid nodule. Page 47 of 65

48 Fig. 28: Strong hypoechogenicity. Fig. 29: Cystic lesion with a solid peripheral component. Page 48 of 65

49 Fig. 30: Cystic lesion with multiple tabications. Fig. 31: Suspicious lymphadenopathy, cystic component and microcalcifications are shown. Page 49 of 65

50 Fig. 32: Colloid component and spongiform appearance in thyroid nodule. Fig. 33: Microcalcifications in papillary carcinoma. Page 50 of 65

51 Fig. 34: Coarse calcifications within thyroid nodule with acoustic shadowing. Fig. 35: Nodule with colloid condensations producing comet tail artifact. Page 51 of 65

52 Fig. 38: Normal laterocervical lymphadenopathy. Fig. 39: Size augmented lymphadenopathy with irregular margins and loss of normal echostructure. Page 52 of 65

53 Fig. 40: Pathologic lymphadenopathy with cystic spaces and microcalcifications. Table 4: Relation between ultrasonographic characteristics and malignancy probability according to Kwak et al. Radiology Page 53 of 65

54 Fig. 41: Ultrasound guided FNA of a thyroid nodule. Fig. 42: Material needed to perform a FNA of a thyroid nodule. Page 54 of 65

55 Fig. 43: Ultrasonographic picture of a nodule during FNA. The orange arrow signals the point of the needle. Page 55 of 65

56 Fig. 44: Multiple nodules with multiples sizes and characteristics. Page 56 of 65

57 Fig. 45: This nodule is smaller than 1 cm. Page 57 of 65

58 Table 5: Comparison between different pathologic nodules classification systems. Radiology 2011 Page 58 of 65

59 Conclusion - Thyroid nodules are a frequent radiologic finding, often incidental. They can be manifestation of various pathology, both benign and malignant, and it is necessary to include them in one group or the other for optimum management. - The ideal imaging study to characterize thyroid nodules is ultrasounds. - The clinical and radiological criteria of malignancy will be determinant to decide whether to monitor, performa pathologic study or a surgical excision. - It is necesary to practice FNA puncture technique in these lesions as they are often small as it is also important to know the recommendations for the selection of the lesion to be punctured in cases of multinodular pathology. - The outlook for the immediate future is to agree in an standardized stratification, probably settled on BIRADS system, so, on the risk of malignancy of the nodule, aiming to avoid unnecessary interventions. - Also, as in other areas, it would be advisable to standardize the language and codes among radiologists, pathologists and endocrinologists, thereby improving the management and monitoring of patients from the cost-effectiveness point of view. Images for this section: Page 59 of 65

60 Table 1: Summary of tumoral thyroid pathology. Page 60 of 65

61 Fig. 29: Cystic lesion with a solid peripheral component. Fig. 10: Simple Cyst. Page 61 of 65

62 Fig. 13: Medular Thyroid Carcinoma. Page 62 of 65

63 Fig. 41: Ultrasound guided FNA of a thyroid nodule. Page 63 of 65

64 References 1-R. Cortázar García, R. Quirós López y M.M. Acebal Blanco. "Papel del radiólogo en el manejo del nódulo tiroideo". Radiología. 2008;50: Frates MC et al. "Management of thyroid nodules detected at US: Society of Radiologists in Ultrasound consensus conference statement." Radiology. 2005;237: Moon WJ et al. "Benign and malignant thyroid nodules: US differentiation--multicenter retrospective study". Radiology 2008;247: Kim MJ, et al. "US-guided fine-needle aspiration of thyroid nodules: indications, techniques, results". Radiographics. 2008;28: Hoang JK, et al. "US Features of thyroid malignancy: pearls and pitfalls". RadioGraphics 2007; 27: Cronan JJ. "Thyroid nodules: is it time to turn off the US machines?". Radiology ;247: American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer, Cooper DS, Doherty GM, et al. Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid 2009 ; 19 ( 11 ): Park JY, Lee HJ, Jang HW, et al. "A proposal for a thyroid imaging reporting and data system for ultrasound features of thyroid carcinoma"". Thyroid 2009 ; 19 ( 11 ): Horvath E, Majlis S, Rossi R, et al. "An ultrasonogram reporting system for thyroid nodules stratifying cancer risk for clinical management". J Clin Endocrinol Metab 2009 ; 94 ( 5 ): Gharib H, Papini E, Valcavi R, et al. "American Association of Clinical Endocrinologists and Associazione Medici Endocrinologi medical guidelines for clinical practice for the diagnosis and management of thyroid nodules". Endocr Pract 2006; 12: Page 64 of 65

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