The radiological spectrum of thyroid malignancy

Transcription

1 The radiological spectrum of thyroid malignancy Poster No.: C-2575 Congress: ECR 2012 Type: Educational Exhibit Authors: K. Cortis, W. Scicluna, A. Mizzi ; Rabat/MT, Birkirkara/MT Keywords: Ultrasound-Colour Doppler, Ultrasound, CT, Thyroid / Parathyroids, Head and neck, Biopsy, Neoplasia DOI: /ecr2012/C 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 50

2 Learning objectives To illustrate the imaging features of thyroid malignancies. To illustrate the current evidence based trends in the sonographic evaluation of thyroid nodules. To provide a diagnostic algorithm for the characterisation of thyroid nodules into benign, indeterminate, and highly suspicious for malignancy. To highlight the need of fine needle aspiration (FNA) of nodules with show indeterminate or suspicious imaging features. Page 2 of 50

3 Background The thyroid gland is ideal for evaluation by high resolution ultrasonography, using a linear array high frequency probe. Its location is superficial, surrounding anatomical structures are constant and the normal texture is homogenous. Sonographic detection of thyroid nodules is common, and is seen in up to 50% of patients undergoing nuchal ultrasound. On the other hand, less than 7% of all thyroid nodules and less than 20% of palpable thyroid noudles are malignant. The main imaging features which should be evaluated following sonographic detection of thyroid nodules are size of the nodule, margins, echogenicity, composition, shape, and intra-nodular vascularity. Combined, these sonographic criteria should guide the clinician in deciding which nodules to biopsy or follow-up, and which nodules to categorise as benign. Page 3 of 50

4 Imaging findings OR Procedure details INTRODUCTION Main sonographic criteria in the evaluation of thyroid nodules: Margins Echogenicity Composition (cystic or solid) Internal punctuate echogenicities Shape Vascularity The sensitivities, specificities, and negative and positive predictive values for these criteria are extremely variable from study to study, and no US feature has both a high sensitivity and positive predictive value for thyroid cancer. Nodule size, homogeneity or heterogeneity of echotexture, and rim calcification are NOT a predictor of malignancy. The incidence of malignancy in multinodular goitre is 1-3%, and malignancy is more likely in a solitary nodule. On the other hand, malignant and benign nodules present simultaneously in 10-20% of cases; and up to 10-20% of papillary carcinomas can be multi-centric. PART 1: SONOGRAPHIC EVALUATION OF THYROID NODULES Criterion No. 1: Margins BENIGN: Well-defined smooth margins (76% of benign), thin hypoechoic halo around the entire nodule (if complete halo is present, 12x more chance that the nodule is benign). An incomplete halo around the nodule also indicates a benign lesion (4x more chance of nodule being benign). A halo may be seen in 15-30% of malignancies. Page 4 of 50

5 Fig. 1: Isoechoic nodule within the left thyroid lobe with a complete hypoechoic halo. FNA showed no malignant cells. References: - Rabat/MT Page 5 of 50

6 Fig. 2: Isoechoic nodule within the left thyroid lobe with an incomplete hypoechoic halo. FNA showed no malignant cells. References: - Rabat/MT MALIGNANT: Irregular or well-defined spiculated margins (81% of malignant), no halo. Page 6 of 50

7 Fig. 3: Hypoechoic nodule at the junction of the left thyroid lobe and isthmus expanding the thyroid contour. Margins are ill defined. FNA showed a papillary thyroid carcinoma. References: - Rabat/MT Ill defined margins are seen in 19% of malignant and 15% of benign! Criterion No. 2: Echogenicity BENIGN: Hyperechoic (96% of hyperechoic are benign, compared to 74% of isoechoic and 39% of hypoechoic). Page 7 of 50

8 Fig. 4: Incidental finding during nuchal ultrasound. A well delineated hyperechoic nodule is seen within the right thyroid lobe. Doppler analysis revealed no increased flow within this nodule (not shown). 96% of all hyperechoic nodules are benign. References: - Rabat/MT Page 8 of 50

9 Fig. 5: Right sided hypoechoic nodule - this was sampled through FNA and shown to be benign. Around 63% of hypoechoic nodules are malignant. References: - Rabat/MT MALIGNANT: Hypoechoic (63% of hypoechoic, 26% of isoechoic, and 4% of hyperechoic are malignant). Page 9 of 50

10 Fig. 6: Multifocal papillary carcinoma. Two hypoechoic nodules with internal punctate calcifications are seen - one at the junction of the thyroid isthmus and right thyroid lobe, the other within the left thyroid lobe. References: - Rabat/MT Criterion No. 3: Consistency Cystic thyroid nodules are usually benign but up to a third of papillary NGs have a cystic component. BENIGN: Most (87%) are predominantly solid. 13% are predominantly cystic, with hyperechoic solid components. Page 10 of 50

11 Fig. 7: Benign 4.3 cm nodule within the right thyroid lobe, with retrosternal extension. This nodule is heterogeneous and mostly isoechoic to the normal thyroid parenchyma. Cystic components are also seen. The patient had similar, albeit smaller, nodules within the isthmus and left thyroid lobe, in keeping with a multinodular goitre. References: - Rabat/MT Page 11 of 50

12 Fig. 8: Benign, predominantly cystic, thyroid nodule. A complete hypoechoic halo is seen. No internal Doppler flow was present in the solid components. References: - Rabat/MT MALIGNANT: 98% NGs are predominantly solid, but one third of papillary carcinomas exhibit cystic degeneration with a cystic component. Page 12 of 50

13 Fig. 9: Large heterogenous, predominantly hyperechoic, nodule with a minor cystic component and with retrosternal extension. This patient had presented with a lump in the occipital region (Figure 16), which was biopsied. Histopathological analysis from the latter revealed a metastatic follicular neoplasm. A FNA of this thyroid nodule was therefore performed, and it was confirmed as being the primary lesion. References: - Rabat/MT Criterion No. 4: Internal punctate echogenicities Punctate echogenicities with comet-tail artefacts are features of benign colloid cysts. The comet tail sign is the only highly specific sign of benignity and its presence almost invariably signifies a benign colloid cyst. Page 13 of 50

14 Fig. 10: Comet-tail artefacts within two colloid cysts in two different patients. An anechoic 3.5 cm colloid cyst with peripheral comet tail artefacts is seen on the left. A small colloid cyst is seen in the midportion of the left thyroid lobe (right), with a central comet tail artefact. References: - Rabat/MT Fine punctate echogenicities with NO comet-tail artefacts represent punctate microcalcifications usually associated with papillary carcinoma. These are too small to produce posterior acoustic shadowing. Page 14 of 50

15 Fig. 11: Punctate echogenicities within an isoechoic thyroid nodule, in keeping with punctate calcifications. Posterior acoustic shadowing is seen due to clumping of these punctate calcifications. FNA revealed a papillary thyroid carcinoma. References: - Rabat/MT Microcalcifications are associated with a 3x increased risk of malignancy, while coarse calcifications are associated with a 2x increased risk. A peripheral/rim type of calcification indicates benignity. Criterion No. 5: Shape 91% of benign are ovoid to round. A 'taller than wide' shape is very specific for malignancy, BUT poorly sensitive since 58% of malignant nodules are ovoid to round! Page 15 of 50

16 'Taller than wide' = anteroposterior diameter of a nodule longer than its transverse diameter on a transverse or longitudinal plane. Criterion No. 6: Vascularity A hypervascular nodule is one in which the flow inside the nodule is more than that in the surrounding parenchyma. Most often, colour Doppler gain settings have to be maximised for slow flow BENIGN: Hypervascular at the periphery and internally hypovascular ('ring of fire'). Page 16 of 50

17 Fig. 12: Isoechoic nodule with a complete hypoechoic halo, and with no detectable internal Doppler flow. These findings are all in keeping with benignity and were confirmed by FNA. References: - Rabat/MT MALIGNANT: Marked intranodule vascularity increases the risk of malignancy. This is defined as flow inside the nodule being more than in the surrounding parenchyma. On the other hand, papillary carcinoma can be hypovascular. Criterion No. 7: Regional lymph nodes The presence of abnormal cervical lymph nodes should prompt biopsy of the abnormal lymph nodes and/or an ipsilateral thyroid nodule of any size % of thyroid carcinomas present as palpable cervical lymph nodes. Metastatic nodes from papillary carcinoma show cystic necrosis in 25% of cases and punctate calcification in 50%; they are hypoechoic relative to muscle in 80%. Fig. 13: Pathological lymph nodes (different patients). Increase in the short to long axis ratio is seen on the left, with the enlarged lymph node assuming an oval shape. A peripheral pattern of flow (as opposed to the physiological hilar pattern) is seen. A disorganised interrupted peripheral pattern of flow is also seen on the left, together with internal nodal punctate calcifications. Both patients had a papillary thyroid carcinoma. References: - Rabat/MT Metastatic lymph nodes from medullary carcinoma show echogenic foci; they are invariably hypoechoic relative to adjacent muscles. Page 17 of 50

18 Other sonographic features of malignant lymph nodes include: Iincreased short to long axis ratio (i.e. round shape) Absence of the echogenic fatty hilum Heterogeneous cortex Ill defined margins in keeping with invasion of the adjacent anatomical structures Disorganised peripheral pattern of flow with areas of relative avascularity (in keeping with areas of necrosis) PART 2: TYPES OF THYROID CARCINOMA Can be subdivided into: Papillary carcinoma (approx. 71%) Follicular neoplasms (approx. 14%) Medullary carcinoma (approx. 4%) Anaplastic carcinoma (approx. 4%) Lymphoma (approx 3%) Other aetiologies including metastases (approx 4%) Papillary carcinoma This is the most common type of thyroid cancer, with most patients being female. Prognosis is excellent, with a 20 year survival rate above 90%. Poor prognostic signs include male sex, old age at presentation, large size, and extracapsular or vascular invasion. Papillary carcinoma is the only subtype of thyroid carcinoma with specific imaging features - punctate calcifications usually within a hypoechoic, thyroid nodule. Papillary carcinomas have a propensity for lymphatic spread. Lymph node metastasis often contain identical punctate microcalcifications. Up to one third of papillary carcinomas exhibit cystic degeneration with a cystic component. Page 18 of 50

19 Fig. 3: Hypoechoic nodule at the junction of the left thyroid lobe and isthmus expanding the thyroid contour. Margins are ill defined. FNA showed a papillary thyroid carcinoma. References: - Rabat/MT Page 19 of 50

20 Fig. 6: Multifocal papillary carcinoma. Two hypoechoic nodules with internal punctate calcifications are seen - one at the junction of the thyroid isthmus and right thyroid lobe, the other within the left thyroid lobe. References: - Rabat/MT Page 20 of 50

21 Fig. 11: Punctate echogenicities within an isoechoic thyroid nodule, in keeping with punctate calcifications. Posterior acoustic shadowing is seen due to clumping of these punctate calcifications. FNA revealed a papillary thyroid carcinoma. References: - Rabat/MT Page 21 of 50

22 Fig. 13: Pathological lymph nodes (different patients). Increase in the short to long axis ratio is seen on the left, with the enlarged lymph node assuming an oval shape. A peripheral pattern of flow (as opposed to the physiological hilar pattern) is seen. A disorganised interrupted peripheral pattern of flow is also seen on the left, together with internal nodal punctate calcifications. Both patients had a papillary thyroid carcinoma. References: - Rabat/MT Page 22 of 50

23 Fig. 14: Multifocal papillary carincoma in a 35 year old male (two views of the same nodule are shown). A cystic component is evident. The internal punctate echogenicities were difficult to differentiate from comet tail artefacts, and FNA was performed on the basis that this nodule was 3.5 cm in diameter, and showed increased internal Doppler flow (not shown). Pathological ipsilateral lymph nodes were also seen (refer to Figure 15). References: - Rabat/MT Fig. 15: Lymph node metastases with cystic degeneration from the same patient as in Figure 14. Complete absence of the central fatty hilum is seen, together with widespread punctate calcifications. References: - Rabat/MT Follicular neoplasms Benign follicular adenomas and malignant follicular carcinomas cannot be distinguished by imaging or by imaging guided fine needle aspiration (FNA) / biopsy. Follicular neoplasms are therefore usually surgically excised and examined histologically. No specific imaging features are seen in follicular neoplasms. Follicular carcinomas can spread haematogeneously, and patients can present with symptoms and signs related to distant metastases. Lymphatic spread is uncommon. Page 23 of 50

24 Fig. 9: Large heterogenous, predominantly hyperechoic, nodule with a minor cystic component and with retrosternal extension. This patient had presented with a lump in the occipital region (Figure 16), which was biopsied. Histopathological analysis from the latter revealed a metastatic follicular neoplasm. A FNA of this thyroid nodule was therefore performed, and it was confirmed as being the primary lesion. References: - Rabat/MT Fig. 16: Metastatic follicular carcinoma in an elderly lady presenting with a large occipital lump (same patient as Figure 6). Selected image from an axial CT in bone Page 24 of 50

25 window settings reveals a large osteolytic lesion replacing most of the occipital bone (left). Ultrasonography of this region shows that this lump is of an echogenicity distinct from the brain, and confirms its extra-axial location (middle). As seen on this selected colour Doppler image (top right), this lesion is highly vascular. Isotope bone scan (bottom right) showing a photopaenic defect in the occiptal region, corresponding to this lump, and two foci of increased uptake close to the vertex (which were also confirmed as being osteolytic metastastic deposits from the thyroid follicular carcinoma). References: - Rabat/MT Fig. 17: Metastatic follicular carcinoma in a 38 year old female. This patient initially presented to her dental surgeon with mandibular pain. An ortho-panto-gram shows a lytic lesion located at the left sided portion of the mandibular bone. This lytic lesion has a wide zone of transition, and is in keeping with an aggressive bone lesion. Bone scintigraphy shows increased uptake of isotope in the corresponding region. References: - Rabat/MT Page 25 of 50

26 Fig. 18: Metastatic follicular carcinoma in a 38 year old female (same patient as in Figure 17). Further osteolytic metastatic deposits in the rib cage as seen on chest radiography (left), axial and reformatted CT (right upper and middle images) and bone scintigraphy (bottom right). Follicular carcinoma of the thyroid is a known cause of bone metastases with a large soft tissue component and florid bone destruction. Metastatic renal cell carcinoma is another tumour associated with this osteolytic pattern. References: - Rabat/MT Hürthle cell carcinoma is a rare variant of follicular carcinoma, again with no specific sonographic features. Imaging or image guided FNA cannot distinguish between an aggressive and a non-aggressive Hürthle cell neoplasm. Page 26 of 50

27 Fig. 19: Two different patients with a Hurthle cell neoplasm. A hypoechoic nodule is seen within the left thyroid lobe of the first patient (left) - this was confirmed to have no malignant potential following surgical excision. A larger hypoechoic nodule is seen within the right thyroid lobe of the second patient (right). Doppler analysis revealed increased flow within this nodule. Hemithyroidectomy confirmed a Hurthle cell carcinoma. References: - Rabat/MT Medullary carcinoma Medullary carcinomas arise from the parafollicular c-cells which secrete calcitonin % of cases are familial and are associated with Multiple Endocrine Neoplasia (MEN) syndrome II. Nodal metastases are seen in 50% and distant metastases in 15-25% of patients. Ultrasound features are non specific and include: Solid hypo-echoic nodule Focal (predominantly in the upper third of the gland) in the sporadic form or diffuse involvement of both lobes in the familial form Echogenic foci (representing dense deposits of amyloid and associated focal calcification) Disordered vascular pattern on colour flow imaging Associated characteristic lymphadenopathy with echogenic intra-nodal foci). Page 27 of 50

28 Fig. 20: Hypoechoic ellipsoidal nodule within the left thyroid lobe with internal punctuate echogenicities. FNA was performed since the findings were considered as being highly suspicious for papillary thyroid carcinoma. A mucinous carcinoma was subsequently diagnosed - the punctate echogenicities in this rare type of thyroid carcinoma are due to dense deposits of amyloid and associated calcifications. References: - Rabat/MT Anaplastic carcinoma Anaplastic thyroid carcinoma is rare, and is generally considered as one of the most aggressive head and neck cancers with survival rates of only a few months. Patients usually present with a rapidly growing thyroid nodule which is causing pressure signs and symptoms. Nodal or distant metastases are seen in 80% of patients. Ultrasound features are again non-specific. Invasion of the adjacent vessels and lymphadenopathy is a common feature. Page 28 of 50

29 Fig. 21: Patient presenting with a rapidly enlarging neck mass. Selected axial CT image shows infiltration of the platysma and prevertebral muscles. Encasement of the right common carotid artery is also seen. Apparent extension and direct invasion of the right side of the hypopharynx is also seen. References: Dr Corinne Binns, Dr David Salvage. (2007, Mar 5). Anaplastic Thyroid Cancer, {Online}. URL: DOI: / EURORAD/CASE.5394 Page 29 of 50

30 Images for this section: Fig. 1: Isoechoic nodule within the left thyroid lobe with a complete hypoechoic halo. FNA showed no malignant cells. - Rabat/MT Page 30 of 50

31 Fig. 2: Isoechoic nodule within the left thyroid lobe with an incomplete hypoechoic halo. FNA showed no malignant cells. - Rabat/MT Page 31 of 50

32 Fig. 3: Hypoechoic nodule at the junction of the left thyroid lobe and isthmus expanding the thyroid contour. Margins are ill defined. FNA showed a papillary thyroid carcinoma. - Rabat/MT Page 32 of 50

33 Fig. 4: Incidental finding during nuchal ultrasound. A well delineated hyperechoic nodule is seen within the right thyroid lobe. Doppler analysis revealed no increased flow within this nodule (not shown). 96% of all hyperechoic nodules are benign. - Rabat/MT Page 33 of 50

34 Fig. 5: Right sided hypoechoic nodule - this was sampled through FNA and shown to be benign. Around 63% of hypoechoic nodules are malignant. - Rabat/MT Page 34 of 50

35 Fig. 6: Multifocal papillary carcinoma. Two hypoechoic nodules with internal punctate calcifications are seen - one at the junction of the thyroid isthmus and right thyroid lobe, the other within the left thyroid lobe. - Rabat/MT Page 35 of 50

36 Fig. 7: Benign 4.3 cm nodule within the right thyroid lobe, with retrosternal extension. This nodule is heterogeneous and mostly isoechoic to the normal thyroid parenchyma. Cystic components are also seen. The patient had similar, albeit smaller, nodules within the isthmus and left thyroid lobe, in keeping with a multinodular goitre. - Rabat/MT Page 36 of 50

37 Fig. 8: Benign, predominantly cystic, thyroid nodule. A complete hypoechoic halo is seen. No internal Doppler flow was present in the solid components. - Rabat/MT Page 37 of 50

38 Fig. 9: Large heterogenous, predominantly hyperechoic, nodule with a minor cystic component and with retrosternal extension. This patient had presented with a lump in the occipital region (Figure 16), which was biopsied. Histopathological analysis from the latter revealed a metastatic follicular neoplasm. A FNA of this thyroid nodule was therefore performed, and it was confirmed as being the primary lesion. - Rabat/MT Page 38 of 50

39 Fig. 10: Comet-tail artefacts within two colloid cysts in two different patients. An anechoic 3.5 cm colloid cyst with peripheral comet tail artefacts is seen on the left. A small colloid cyst is seen in the midportion of the left thyroid lobe (right), with a central comet tail artefact. - Rabat/MT Fig. 11: Punctate echogenicities within an isoechoic thyroid nodule, in keeping with punctate calcifications. Posterior acoustic shadowing is seen due to clumping of these punctate calcifications. FNA revealed a papillary thyroid carcinoma. - Rabat/MT Page 39 of 50

40 Fig. 12: Isoechoic nodule with a complete hypoechoic halo, and with no detectable internal Doppler flow. These findings are all in keeping with benignity and were confirmed by FNA. - Rabat/MT Page 40 of 50

41 Fig. 13: Pathological lymph nodes (different patients). Increase in the short to long axis ratio is seen on the left, with the enlarged lymph node assuming an oval shape. A peripheral pattern of flow (as opposed to the physiological hilar pattern) is seen. A disorganised interrupted peripheral pattern of flow is also seen on the left, together with internal nodal punctate calcifications. Both patients had a papillary thyroid carcinoma. - Rabat/MT Page 41 of 50

42 Fig. 14: Multifocal papillary carincoma in a 35 year old male (two views of the same nodule are shown). A cystic component is evident. The internal punctate echogenicities were difficult to differentiate from comet tail artefacts, and FNA was performed on the basis that this nodule was 3.5 cm in diameter, and showed increased internal Doppler flow (not shown). Pathological ipsilateral lymph nodes were also seen (refer to Figure 15). - Rabat/MT Fig. 15: Lymph node metastases with cystic degeneration from the same patient as in Figure 14. Complete absence of the central fatty hilum is seen, together with widespread punctate calcifications. - Rabat/MT Page 42 of 50

43 Fig. 16: Metastatic follicular carcinoma in an elderly lady presenting with a large occipital lump (same patient as Figure 6). Selected image from an axial CT in bone window settings reveals a large osteolytic lesion replacing most of the occipital bone (left). Ultrasonography of this region shows that this lump is of an echogenicity distinct from the brain, and confirms its extra-axial location (middle). As seen on this selected colour Doppler image (top right), this lesion is highly vascular. Isotope bone scan (bottom right) showing a photopaenic defect in the occiptal region, corresponding to this lump, and two foci of increased uptake close to the vertex (which were also confirmed as being osteolytic metastastic deposits from the thyroid follicular carcinoma). - Rabat/MT Fig. 17: Metastatic follicular carcinoma in a 38 year old female. This patient initially presented to her dental surgeon with mandibular pain. An ortho-panto-gram shows a lytic lesion located at the left sided portion of the mandibular bone. This lytic lesion has a wide zone of transition, and is in keeping with an aggressive bone lesion. Bone scintigraphy shows increased uptake of isotope in the corresponding region. - Rabat/MT Page 43 of 50

44 Fig. 18: Metastatic follicular carcinoma in a 38 year old female (same patient as in Figure 17). Further osteolytic metastatic deposits in the rib cage as seen on chest radiography (left), axial and reformatted CT (right upper and middle images) and bone scintigraphy (bottom right). Follicular carcinoma of the thyroid is a known cause of bone metastases with a large soft tissue component and florid bone destruction. Metastatic renal cell carcinoma is another tumour associated with this osteolytic pattern. - Rabat/MT Page 44 of 50

45 Fig. 19: Two different patients with a Hurthle cell neoplasm. A hypoechoic nodule is seen within the left thyroid lobe of the first patient (left) - this was confirmed to have no malignant potential following surgical excision. A larger hypoechoic nodule is seen within the right thyroid lobe of the second patient (right). Doppler analysis revealed increased flow within this nodule. Hemithyroidectomy confirmed a Hurthle cell carcinoma. - Rabat/MT Fig. 20: Hypoechoic ellipsoidal nodule within the left thyroid lobe with internal punctuate echogenicities. FNA was performed since the findings were considered as being highly suspicious for papillary thyroid carcinoma. A mucinous carcinoma was subsequently diagnosed - the punctate echogenicities in this rare type of thyroid carcinoma are due to dense deposits of amyloid and associated calcifications. - Rabat/MT Page 45 of 50

46 Fig. 21: Patient presenting with a rapidly enlarging neck mass. Selected axial CT image shows infiltration of the platysma and prevertebral muscles. Encasement of the right common carotid artery is also seen. Apparent extension and direct invasion of the right side of the hypopharynx is also seen. Dr Corinne Binns, Dr David Salvage. (2007, Mar 5). Anaplastic Thyroid Cancer, {Online}. URL: DOI: /EURORAD/ CASE.5394 Page 46 of 50

47 Conclusion Sonographic evaluation of thyroid nodules Sonographic Criteria Benign Malignant Margins Well-defined smooth margins (76% of benign), thin hypoechoic halo around the entire nodule (if halo is present, 12x more chance that the nodule is benign). Irregular or well-defined spiculated margins (81% of malignant), no halo (Se = 17-77%; Sp = 85-95%). Ill defined margins are seen in 19% of malignant and 15% of benign! Echogenicity Hyperechoic (96% of hyperechoic are benign, compared to 74% of isoechoic and 39% of hypoechoic). Hypoechoic (Se = 27-87%; Sp = 24-71%; % of all thyroid cancers are hypoechoic, however a hypoechoic nodule is still more likely to be benign since 90% of all nodules are benign). Consistency Most (87%) are predominantly solid. 13% are predominantly cystic, with hyperechoic solid components. One third of thyroid malignancies exhibit cystic degeneration, but most (98%) NGs are predominantly solid (Se 69-75%; Sp = 52-55%). Punctuate echogenicities Punctuate echogenicities with comet-tail artefacts are features of benign colloid cysts. Fine punctuate echogenicities with NO comet-tail artefacts = punctuate microcalcifications usually associated with papillary carcinoma (Se 26-59%; Sp 86-95%). Microcalcifications are associated with a 3x increased risk of malignancy, while coarse calcifications are Page 47 of 50

48 associated with increased risk. a 2x Shape Ovoid to round (91% of benign). Taller than wide (Se = 33%; Sp = 93%). However, 58% of malignant nodules are ovoid to round! Vascularity Hypervascular at the Marked intranodule periphery and internally vascularity increases the hypovascular ('ring of fire'). risk of malignancy (Se = 54-74%, Sp = 79-81%). Papillary carcinoma can be hypovascular. As per the Society of Radiologists in Ultrasound Consensus Conference Statement, Fine Needle Aspiration (FNA) of thyroid nodules is indicated in: Solitary nodules > 1 cm with punctuate calcifications Predominantly solid nodules or nodules with coarse calcifications > 1.5 cm Mixed solid and cystic nodules, or cystic nodules with solid mural components > 2 cm Nodules showing interval growth on serial imaging Nodules which do not fall in the above categories, but with associated ipsilateral cervical lymphadenopathy Page 48 of 50

49 Personal Information Page 49 of 50

50 References Frates MC et al. Management of thyroid nodules detected at US: Society of Radiologists in Ultrasound consensus conference statement. Ultrasound Q Dec;22(4):231-8; discussion Hoang JK et al. US Features of thyroid malignancy: pearls and pitfalls. Radiographics May-Jun;27(3):847-60; discussion Page 50 of 50