Page 1 of 47

The radiological spectrum of thyroid malignancy

Poster No.: C-2575

Congress: ECR 2012

Type: Educational Exhibit

Authors: K. Cortis1, W. Scicluna2, A. Mizzi2; 1Rabat/MT, 2Birkirkara/MT

Keywords: Ultrasound-Colour Doppler, Ultrasound, CT, Thyroid /Parathyroids, Head and neck, Biopsy, Neoplasia

DOI: 10.1594/ecr2012/C-2575

Any information contained in this pdf file is automatically generated from digital materialsubmitted to EPOS by third parties in the form of scientific presentations. Referencesto any names, marks, products, or services of third parties or hypertext links to third-party sites or information are provided solely as a convenience to you and do not inany way constitute or imply ECR's endorsement, sponsorship or recommendation of thethird party, information, product or service. ECR is not responsible for the content ofthese pages and does not make any representations regarding the content or accuracyof material in this file.As per copyright regulations, any unauthorised use of the material or parts thereof aswell as commercial reproduction or multiple distribution by any traditional or electronicallybased reproduction/publication method ist strictly prohibited.You agree to defend, indemnify, and hold ECR harmless from and against any and allclaims, damages, costs, and expenses, including attorneys' fees, arising from or relatedto your use of these pages.Please note: Links to movies, ppt slideshows and any other multimedia files are notavailable in the pdf version of presentations.www.myESR.org

Page 2 of 47

Learning objectives

1. To illustrate the imaging features of thyroid malignancies.2. To illustrate the current evidence based trends in the sonographic evaluation

of thyroid nodules.3. To provide a diagnostic algorithm for the characterisation of thyroid nodules

into benign, indeterminate, and highly suspicious for malignancy.4. To highlight the need of fine needle aspiration (FNA) of nodules with show

indeterminate or suspicious imaging features.

Background

The thyroid gland is ideal for evaluation by high resolution ultrasonography, using a lineararray high frequency probe. Its location is superficial, surrounding anatomical structuresare constant and the normal texture is homogenous.

Sonographic detection of thyroid nodules is common, and is seen in up to 50% of patientsundergoing nuchal ultrasound. On the other hand, less than 7% of all thyroid nodules andless than 20% of palpable thyroid noudles are malignant.

The main imaging features which should be evaluated following sonographic detection ofthyroid nodules are size of the nodule, margins, echogenicity, composition, shape, andintra-nodular vascularity. Combined, these sonographic criteria should guide the clinicianin deciding which nodules to biopsy or follow-up, and which nodules to categorise asbenign.

Imaging findings OR Procedure details

INTRODUCTION

Main sonographic criteria in the evaluation of thyroid nodules:

1. Margins2. Echogenicity3. Composition (cystic or solid)4. Internal punctuate echogenicities5. Shape

Page 3 of 47

6. Vascularity

The sensitivities, specificities, and negative and positive predictive values for thesecriteria are extremely variable from study to study, and no US feature has both a highsensitivity and positive predictive value for thyroid cancer.

Nodule size, homogeneity or heterogeneity of echotexture, and rim calcification are NOTa predictor of malignancy.

The incidence of malignancy in multinodular goitre is 1-3%, and malignancy is morelikely in a solitary nodule. On the other hand, malignant and benign nodules presentsimultaneously in 10-20% of cases; and up to 10-20% of papillary carcinomas can bemulti-centric.

PART 1: SONOGRAPHIC EVALUATION OF THYROID NODULES

Criterion No. 1: Margins

BENIGN: Well-defined smooth margins (76% of benign), thin hypoechoic halo around theentire 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 chanceof nodule being benign).

A halo may be seen in 15-30% of malignancies.

Page 4 of 47

Fig. 1: Isoechoic nodule within the left thyroid lobe with a complete hypoechoic halo.FNA showed no malignant cells.References: K. Cortis; Rabat, MALTA

Page 5 of 47

Fig. 2: Isoechoic nodule within the left thyroid lobe with an incomplete hypoechoichalo. FNA showed no malignant cells.References: K. Cortis; Rabat, MALTAMALIGNANT: Irregular or well-defined spiculated margins (81% of malignant), no halo.

Page 6 of 47

Fig. 3: Hypoechoic nodule at the junction of the left thyroid lobe and isthmusexpanding the thyroid contour. Margins are ill defined. FNA showed a papillary thyroidcarcinoma.References: K. Cortis; Rabat, MALTAIll 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 isoechoicand 39% of hypoechoic).

Page 7 of 47

Fig. 4: Incidental finding during nuchal ultrasound. A well delineated hyperechoicnodule is seen within the right thyroid lobe. Doppler analysis revealed no increasedflow within this nodule (not shown). 96% of all hyperechoic nodules are benign.References: K. Cortis; Rabat, MALTA

Page 8 of 47

Fig. 5: Right sided hypoechoic nodule - this was sampled through FNA and shown tobe benign. Around 63% of hypoechoic nodules are malignant.References: K. Cortis; Rabat, MALTAMALIGNANT: Hypoechoic (63% of hypoechoic, 26% of isoechoic, and 4% of hyperechoicare malignant).

Page 9 of 47

Fig. 6: Multifocal papillary carcinoma. Two hypoechoic nodules with internal punctatecalcifications are seen - one at the junction of the thyroid isthmus and right thyroid lobe,the other within the left thyroid lobe.References: K. Cortis; Rabat, MALTA

Criterion No. 3: Consistency

Cystic thyroid nodules are usually benign but up to a third of papillary NGs have a cysticcomponent.

BENIGN: Most (87%) are predominantly solid. 13% are predominantly cystic, withhyperechoic solid components.

Page 10 of 47

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, noduleswithin the isthmus and left thyroid lobe, in keeping with a multinodular goitre.References: K. Cortis; Rabat, MALTA

Page 11 of 47

Fig. 8: Benign, predominantly cystic, thyroid nodule. A complete hypoechoic halo isseen. No internal Doppler flow was present in the solid components.References: K. Cortis; Rabat, MALTAMALIGNANT: 98% NGs are predominantly solid, but one third of papillary carcinomasexhibit cystic degeneration with a cystic component.

Page 12 of 47

Fig. 9: Large heterogenous, predominantly hyperechoic, nodule with a minor cysticcomponent and with retrosternal extension. This patient had presented with a lump inthe occipital region (Figure 16), which was biopsied. Histopathological analysis fromthe latter revealed a metastatic follicular neoplasm. A FNA of this thyroid nodule wastherefore performed, and it was confirmed as being the primary lesion.References: K. Cortis; Rabat, MALTA

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 almostinvariably signifies a benign colloid cyst.

Page 13 of 47

Fig. 10: Comet-tail artefacts within two colloid cysts in two different patients. Ananechoic 3.5 cm colloid cyst with peripheral comet tail artefacts is seen on the left. Asmall colloid cyst is seen in the midportion of the left thyroid lobe (right), with a centralcomet tail artefact.References: K. Cortis; Rabat, MALTA

Fine punctate echogenicities with NO comet-tail artefacts represent punctatemicrocalcifications usually associated with papillary carcinoma. These are too small toproduce posterior acoustic shadowing.

Page 14 of 47

Fig. 11: Punctate echogenicities within an isoechoic thyroid nodule, in keeping withpunctate calcifications. Posterior acoustic shadowing is seen due to clumping of thesepunctate calcifications. FNA revealed a papillary thyroid carcinoma.References: K. Cortis; Rabat, MALTAMicrocalcifications are associated with a 3x increased risk of malignancy, while coarsecalcifications are associated with a 2x increased risk. A peripheral/rim type of calcificationindicates 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 47

'Taller than wide' = anteroposterior diameter of a nodule longer than its transversediameter 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 thesurrounding parenchyma. Most often, colour Doppler gain settings have to be maximisedfor slow flow

BENIGN: Hypervascular at the periphery and internally hypovascular ('ring of fire').

Page 16 of 47

Fig. 12: Isoechoic nodule with a complete hypoechoic halo, and with no detectableinternal Doppler flow. These findings are all in keeping with benignity and wereconfirmed by FNA.References: K. Cortis; Rabat, MALTAMALIGNANT: Marked intranodule vascularity increases the risk of malignancy. This isdefined as flow inside the nodule being more than in the surrounding parenchyma. Onthe 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 abnormallymph nodes and/or an ipsilateral thyroid nodule of any size. 15-30% of thyroidcarcinomas present as palpable cervical lymph nodes.

Metastatic nodes from papillary carcinoma show cystic necrosis in 25% of cases andpunctate calcification in 50%; they are hypoechoic relative to muscle in 80%.

Fig. 13: Pathological lymph nodes (different patients). Increase in the short to longaxis 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. Adisorganised interrupted peripheral pattern of flow is also seen on the left, together withinternal nodal punctate calcifications. Both patients had a papillary thyroid carcinoma.References: K. Cortis; Rabat, MALTAMetastatic lymph nodes from medullary carcinoma show echogenic foci; they areinvariably hypoechoic relative to adjacent muscles.

Page 17 of 47

Other sonographic features of malignant lymph nodes include:

1. Iincreased short to long axis ratio (i.e. round shape)2. Absence of the echogenic fatty hilum3. Heterogeneous cortex4. Ill defined margins in keeping with invasion of the adjacent anatomical

structures5. 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:

1. Papillary carcinoma (approx. 71%)2. Follicular neoplasms (approx. 14%)3. Medullary carcinoma (approx. 4%)4. Anaplastic carcinoma (approx. 4%)5. Lymphoma (approx 3%)6. 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 extra-capsular or vascular invasion.

Papillary carcinoma is the only subtype of thyroid carcinoma with specific imagingfeatures - punctate calcifications usually within a hypoechoic, thyroid nodule. Papillarycarcinomas have a propensity for lymphatic spread. Lymph node metastasis often containidentical punctate microcalcifications.

Up to one third of papillary carcinomas exhibit cystic degeneration with a cysticcomponent.

Page 18 of 47

Fig. 3: Hypoechoic nodule at the junction of the left thyroid lobe and isthmusexpanding the thyroid contour. Margins are ill defined. FNA showed a papillary thyroidcarcinoma.References: K. Cortis; Rabat, MALTA

Page 19 of 47

Fig. 6: Multifocal papillary carcinoma. Two hypoechoic nodules with internal punctatecalcifications are seen - one at the junction of the thyroid isthmus and right thyroid lobe,the other within the left thyroid lobe.References: K. Cortis; Rabat, MALTA

Page 20 of 47

Fig. 11: Punctate echogenicities within an isoechoic thyroid nodule, in keeping withpunctate calcifications. Posterior acoustic shadowing is seen due to clumping of thesepunctate calcifications. FNA revealed a papillary thyroid carcinoma.References: K. Cortis; Rabat, MALTA

Page 21 of 47

Fig. 13: Pathological lymph nodes (different patients). Increase in the short to longaxis 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. Adisorganised interrupted peripheral pattern of flow is also seen on the left, together withinternal nodal punctate calcifications. Both patients had a papillary thyroid carcinoma.References: K. Cortis; Rabat, MALTA

Page 22 of 47

Fig. 14: Multifocal papillary carincoma in a 35 year old male (two views of the samenodule are shown). A cystic component is evident. The internal punctate echogenicitieswere difficult to differentiate from comet tail artefacts, and FNA was performed on thebasis that this nodule was 3.5 cm in diameter, and showed increased internal Dopplerflow (not shown). Pathological ipsilateral lymph nodes were also seen (refer to Figure15).References: K. Cortis; Rabat, MALTA

Fig. 15: Lymph node metastases with cystic degeneration from the same patientas in Figure 14. Complete absence of the central fatty hilum is seen, together withwidespread punctate calcifications.References: K. Cortis; Rabat, MALTA

Follicular neoplasms

Benign follicular adenomas and malignant follicular carcinomas cannot be distinguishedby imaging or by imaging guided fine needle aspiration (FNA) / biopsy. Follicularneoplasms are therefore usually surgically excised and examined histologically.

No specific imaging features are seen in follicular neoplasms. Follicular carcinomas canspread haematogeneously, and patients can present with symptoms and signs relatedto distant metastases. Lymphatic spread is uncommon.

Page 23 of 47

Fig. 9: Large heterogenous, predominantly hyperechoic, nodule with a minor cysticcomponent and with retrosternal extension. This patient had presented with a lump inthe occipital region (Figure 16), which was biopsied. Histopathological analysis fromthe latter revealed a metastatic follicular neoplasm. A FNA of this thyroid nodule wastherefore performed, and it was confirmed as being the primary lesion.References: K. Cortis; Rabat, MALTA

Fig. 16: Metastatic follicular carcinoma in an elderly lady presenting with a largeoccipital lump (same patient as Figure 6). Selected image from an axial CT in bone

Page 24 of 47

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 distinctfrom the brain, and confirms its extra-axial location (middle). As seen on this selectedcolour Doppler image (top right), this lesion is highly vascular. Isotope bone scan(bottom right) showing a photopaenic defect in the occiptal region, correspondingto this lump, and two foci of increased uptake close to the vertex (which werealso confirmed as being osteolytic metastastic deposits from the thyroid follicularcarcinoma).References: K. Cortis; Rabat, MALTA

Fig. 17: Metastatic follicular carcinoma in a 38 year old female. This patient initiallypresented to her dental surgeon with mandibular pain. An ortho-panto-gram showsa lytic lesion located at the left sided portion of the mandibular bone. This lytic lesionhas a wide zone of transition, and is in keeping with an aggressive bone lesion. Bonescintigraphy shows increased uptake of isotope in the corresponding region.References: K. Cortis; Rabat, MALTA

Page 25 of 47

Fig. 18: Metastatic follicular carcinoma in a 38 year old female (same patient as inFigure 17). Further osteolytic metastatic deposits in the rib cage as seen on chestradiography (left), axial and reformatted CT (right upper and middle images) and bonescintigraphy (bottom right). Follicular carcinoma of the thyroid is a known cause of bonemetastases with a large soft tissue component and florid bone destruction. Metastaticrenal cell carcinoma is another tumour associated with this osteolytic pattern.References: K. Cortis; Rabat, MALTA

Hürthle cell carcinoma is a rare variant of follicular carcinoma, again with no specificsonographic features. Imaging or image guided FNA cannot distinguish between anaggressive and a non-aggressive Hürthle cell neoplasm.

Page 26 of 47

Fig. 19: Two different patients with a Hurthle cell neoplasm. A hypoechoic noduleis seen within the left thyroid lobe of the first patient (left) - this was confirmed tohave no malignant potential following surgical excision. A larger hypoechoic noduleis seen within the right thyroid lobe of the second patient (right). Doppler analysisrevealed increased flow within this nodule. Hemithyroidectomy confirmed a Hurthle cellcarcinoma.References: K. Cortis; Rabat, MALTA

Medullary carcinoma

Medullary carcinomas arise from the parafollicular c-cells which secrete calcitonin. 10-20% 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% ofpatients.

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 47

Fig. 20: Hypoechoic ellipsoidal nodule within the left thyroid lobe with internalpunctuate echogenicities. FNA was performed since the findings were consideredas being highly suspicious for papillary thyroid carcinoma. A mucinous carcinomawas subsequently diagnosed - the punctate echogenicities in this rare type of thyroidcarcinoma are due to dense deposits of amyloid and associated calcifications.References: K. Cortis; Rabat, MALTA

Anaplastic carcinoma

Anaplastic thyroid carcinoma is rare, and is generally considered as one of the mostaggressive head and neck cancers with survival rates of only a few months. Patientsusually present with a rapidly growing thyroid nodule which is causing pressure signs andsymptoms. Nodal or distant metastases are seen in 80% of patients.

Ultrasound features are again non-specific. Invasion of the adjacent vessels andlymphadenopathy is a common feature.

Page 28 of 47

Fig. 21: Patient presenting with a rapidly enlarging neck mass. Selected axial CTimage shows infiltration of the platysma and prevertebral muscles. Encasement of theright common carotid artery is also seen. Apparent extension and direct invasion of theright side of the hypopharynx is also seen.References: Dr Corinne Binns, Dr David Salvage. (2007, Mar 5). Anaplastic ThyroidCancer, {Online}. URL: http://www.eurorad.org/case.php?id=5394 DOI: 10.1594/EURORAD/CASE.5394

Images for this section:

Page 29 of 47

Fig. 1: Isoechoic nodule within the left thyroid lobe with a complete hypoechoic halo. FNAshowed no malignant cells.

Page 30 of 47

Fig. 2: Isoechoic nodule within the left thyroid lobe with an incomplete hypoechoic halo.FNA showed no malignant cells.

Page 31 of 47

Fig. 3: Hypoechoic nodule at the junction of the left thyroid lobe and isthmus expandingthe thyroid contour. Margins are ill defined. FNA showed a papillary thyroid carcinoma.

Page 32 of 47

Fig. 4: Incidental finding during nuchal ultrasound. A well delineated hyperechoic noduleis seen within the right thyroid lobe. Doppler analysis revealed no increased flow withinthis nodule (not shown). 96% of all hyperechoic nodules are benign.

Page 33 of 47

Fig. 5: Right sided hypoechoic nodule - this was sampled through FNA and shown to bebenign. Around 63% of hypoechoic nodules are malignant.

Page 34 of 47

Fig. 6: Multifocal papillary carcinoma. Two hypoechoic nodules with internal punctatecalcifications are seen - one at the junction of the thyroid isthmus and right thyroid lobe,the other within the left thyroid lobe.

Page 35 of 47

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 withinthe isthmus and left thyroid lobe, in keeping with a multinodular goitre.

Page 36 of 47

Fig. 8: Benign, predominantly cystic, thyroid nodule. A complete hypoechoic halo is seen.No internal Doppler flow was present in the solid components.

Page 37 of 47

Fig. 9: Large heterogenous, predominantly hyperechoic, nodule with a minor cysticcomponent and with retrosternal extension. This patient had presented with a lump in theoccipital region (Figure 16), which was biopsied. Histopathological analysis from the latterrevealed a metastatic follicular neoplasm. A FNA of this thyroid nodule was thereforeperformed, and it was confirmed as being the primary lesion.

Fig. 10: Comet-tail artefacts within two colloid cysts in two different patients. An anechoic3.5 cm colloid cyst with peripheral comet tail artefacts is seen on the left. A small colloid

Page 38 of 47

cyst is seen in the midportion of the left thyroid lobe (right), with a central comet tailartefact.

Fig. 11: Punctate echogenicities within an isoechoic thyroid nodule, in keeping withpunctate calcifications. Posterior acoustic shadowing is seen due to clumping of thesepunctate calcifications. FNA revealed a papillary thyroid carcinoma.

Page 39 of 47

Fig. 12: Isoechoic nodule with a complete hypoechoic halo, and with no detectableinternal Doppler flow. These findings are all in keeping with benignity and were confirmedby FNA.

Page 40 of 47

Fig. 13: Pathological lymph nodes (different patients). Increase in the short to longaxis 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. Adisorganised interrupted peripheral pattern of flow is also seen on the left, together withinternal nodal punctate calcifications. Both patients had a papillary thyroid carcinoma.

Page 41 of 47

Fig. 14: Multifocal papillary carincoma in a 35 year old male (two views of the samenodule are shown). A cystic component is evident. The internal punctate echogenicitieswere difficult to differentiate from comet tail artefacts, and FNA was performed on thebasis that this nodule was 3.5 cm in diameter, and showed increased internal Dopplerflow (not shown). Pathological ipsilateral lymph nodes were also seen (refer to Figure 15).

Fig. 15: Lymph node metastases with cystic degeneration from the same patient as inFigure 14. Complete absence of the central fatty hilum is seen, together with widespreadpunctate calcifications.

Fig. 16: Metastatic follicular carcinoma in an elderly lady presenting with a large occipitallump (same patient as Figure 6). Selected image from an axial CT in bone windowsettings 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

Page 42 of 47

the brain, and confirms its extra-axial location (middle). As seen on this selected colourDoppler 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 twofoci of increased uptake close to the vertex (which were also confirmed as being osteolyticmetastastic deposits from the thyroid follicular carcinoma).

Fig. 17: Metastatic follicular carcinoma in a 38 year old female. This patient initiallypresented to her dental surgeon with mandibular pain. An ortho-panto-gram shows a lyticlesion located at the left sided portion of the mandibular bone. This lytic lesion has a widezone of transition, and is in keeping with an aggressive bone lesion. Bone scintigraphyshows increased uptake of isotope in the corresponding region.

Page 43 of 47

Fig. 18: Metastatic follicular carcinoma in a 38 year old female (same patient as in Figure17). 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 metastaseswith a large soft tissue component and florid bone destruction. Metastatic renal cellcarcinoma is another tumour associated with this osteolytic pattern.

Page 44 of 47

Fig. 19: Two different patients with a Hurthle cell neoplasm. A hypoechoic nodule isseen within the left thyroid lobe of the first patient (left) - this was confirmed to have nomalignant potential following surgical excision. A larger hypoechoic nodule is seen withinthe right thyroid lobe of the second patient (right). Doppler analysis revealed increasedflow within this nodule. Hemithyroidectomy confirmed a Hurthle cell carcinoma.

Fig. 20: Hypoechoic ellipsoidal nodule within the left thyroid lobe with internal punctuateechogenicities. FNA was performed since the findings were considered as being highlysuspicious for papillary thyroid carcinoma. A mucinous carcinoma was subsequentlydiagnosed - the punctate echogenicities in this rare type of thyroid carcinoma are due todense deposits of amyloid and associated calcifications.

Page 45 of 47

Fig. 21: Patient presenting with a rapidly enlarging neck mass. Selected axial CT imageshows infiltration of the platysma and prevertebral muscles. Encasement of the rightcommon carotid artery is also seen. Apparent extension and direct invasion of the rightside of the hypopharynx is also seen.

Page 46 of 47

Conclusion

Sonographic evaluation of thyroid nodules

Sonographic Criteria Benign Malignant

Margins Well-defined smoothmargins (76% of benign),thin hypoechoic haloaround the entire nodule (ifhalo is present, 12x morechance that the nodule isbenign).

Irregular or well-definedspiculated margins (81% ofmalignant), no halo (Se =17-77%; Sp = 85-95%). Illdefined margins are seenin 19% of malignant and15% of benign!

Echogenicity Hyperechoic (96% ofhyperechoic are benign,compared to 74% ofisoechoic and 39% ofhypoechoic).

Hypoechoic (Se = 27-87%;Sp = 24-71%; 68-100%of all thyroid cancers arehypoechoic, however ahypoechoic nodule is stillmore likely to be benignsince 90% of all nodulesare benign).

Consistency Most (87%) arepredominantly solid. 13%are predominantly cystic,with hyperechoic solidcomponents.

One third of thyroidmalignancies exhibitcystic degeneration, butmost (98%) NGs arepredominantly solid (Se69-75%; Sp = 52-55%).

Punctuate echogenicities Punctuate echogenicitieswith comet-tail artefactsare features of benigncolloid cysts.

Fine punctuateechogenicities with NOcomet-tail artefacts =punctuatemicrocalcifications usuallyassociated with papillarycarcinoma (Se 26-59%; Sp86-95%).

Microcalcifications areassociated with a3x increased riskof malignancy, whilecoarse calcifications are

Page 47 of 47

associated with a 2xincreased risk.

Shape Ovoid to round (91% ofbenign).

Taller than wide (Se =33%; Sp = 93%). However,58% of malignant nodulesare ovoid to round!

Vascularity Hypervascular at theperiphery and internallyhypovascular ('ring of fire').

Marked intranodulevascularity increases therisk of malignancy (Se =54-74%, Sp = 79-81%).Papillary carcinoma can behypovascular.

As per the Society of Radiologists in Ultrasound Consensus Conference Statement, FineNeedle 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

Personal Information

References

Frates MC et al. Management of thyroid nodules detected at US: Society ofRadiologists in Ultrasound consensus conference statement. Ultrasound Q. 2006Dec;22(4):231-8; discussion 239-40.

Hoang JK et al. US Features of thyroid malignancy: pearls and pitfalls.Radiographics. 2007 May-Jun;27(3):847-60; discussion 861-5.