Thyroid Nodule Risk

Stratification and FNA

Guidelines

Mark A. Lupo, MD, FACE, ECNU

Thyroid & Endocrine Center of Florida

Assistant Clinical Professor of Medicine

Florida State University, College of Medicine

Sarasota, Florida

Objectives

Review features of benign and malignant

nodules

Highlight importance of pattern recognition for

risk of malignancy assessment

Introduce ACR TIRADs System

Discuss current guidelines for nodule FNA

US Appearance of Nodules

Composition (solid/cystic)

Echogenicity (darkness on US)

Margins

Presence of calcifications

Shape

Vascularity

High

Suspicion

70-90%

Intermediate

Suspicion

10-20%

Low

Suspicion

5-10%

Very low

Suspicion

<3%

Benign

<1%

ATA 2015: Nodule Sonographic Pattern Risk of Malignancy

Haugen et al. Thyroid; October 2015 (epub)

AACE 2016 Nodule Guidelines

Gharib et al. Endocrine Practice. May 2016

Characteristics Suggesting Low Risk Nodules

Hyperechoic nodule (especially in autoimmune thyroiditis)

Pseudonodules in Hashimoto’s

Pure cyst without a solid component

Colloid within nodule “comet tails”

Spongiform Echotexture

Hyperechoic with background of Hashi’s

Nodule

Hyperechoic with background of Hashi’s

Nodule?

CLEFT SIGN – Due to Fibrosis

Cleft Sign

Right Transverse Right Sagittal

Thick hyperechoic fibrotic band separates the posterior and

anterior components of the lobe in transverse view creating the appearance

of a hypoechoic nodule (arrow) with hyperechoic halo

(note: true halos are only hypoechoic)

In Sagittal view, it is evident that there is no discrete nodule.

Colloid within Nodule with “Comet Tails”

Colloid Within Nodule “Cat’s Eye” (Comet

Tail, Stepladder or Ringdown artifact)

aggregation of multiple

microcystic components

in more than 50% of the

volume of the nodule

“honeycomb of internal

cystic spaces”

Only 1 in 360 spongiform

nodules malignant

99.7% Specificity (Moon)

“Spongiform” nodules

Moon Radiology 2008; 247: 762-70

Bonavita AJR 2009; 193:207-13

Spongiform echotexture

Spongiform Echotexture

Note: Bright Linear Reflectors all

posterior to the microcystic areas

Thin-walled Cyst

Enhancement

Thin-walled Cyst

Complex cyst

Halos & Margins Halo: sonolucent rim around an iso/hyperechoic nodule

representing capsule

Thin/regular – lower risk

Thick/irregular – higher risk

Hypoechoic Nodules ---- Margins:

Smooth and regular

Poorly Defined: interface between nodule and surrounding

parenchyma is difficult to delineate

Lower risk, seen in hyperplastic nodules

Irregular: the demarcation between the nodule and parenchyma

is clearly visible but demonstrates and irregular, infiltrative or

spiculated course.

Higher risk

Halo

Edge Artifact

Halo

No Halo, but a Smooth Margin

Halo

Thin Halo

Benign Follicular AdenomaThick, Irregular Halo

Follicular CA

Subtle differences in halo

Irregular halo

Thinner halo

Isoechoic

Nodules

Margins

Poorly defined, but not

infiltrative (spongiform)Irregular

Infiltrative/Irregular Borders

Suspicious Sonographic Features

Hypoechoic

Microcalcifications

Infiltrative margins

Taller than wide on transverse view

Abnormal cervical lymph nodes

NOT DOPPLER?

Hypoechoic

Compare to strap muscles and SCM

Hypoechoic

Hypoechoic

Markedly Hypoechoic

Compare to strap muscles and SCM

Macrocalcifications: hyperechoic spots with

acoustic shadowing (“dense calcifications”)

Low-intermediate risk

Microcalcifications: hyperechoic spots

without acoustic shadowing (thought to

represent psammoma bodies) (<1mm)

High Risk

Rim (eggshell) calcifications: curvi-linear

hyperechoic calcification along periphery

• Higher risk if interrupted

Calcifications

Macrocalcification Patterns

Kim et al. J Ultrasound Med 2008, 27:1179

Coarse Macrocalcification in PTC

Bonavita AJR 2009; 193:207-13

Eggshell Calcifications with Shadowing

Smooth Eggshell

Maybe Reassuring

Interrupted Eggshell

Not reassuring

PTC in Graves’

Left lobe showing background heterogeneity and a calcified nodule

which proved to be papillary thyroid cancer on FNA biopsy in this patient with

Graves’ Disease.

Microcalcification vs Comet Tail

Microcalcifications

Microcalcifications

Dense and

Microcalcifications

Microcalcifications in Papillary Cancer

May be confused with comet tails

When in doubt - assume the worse

sagittal

NOT microcalcifications!

sagittal

Small hyperechoic linear streaks just

posterior to small cystic area

posterior acoustic enhancement!

Microcalcifications

Calcifications in PTC

LongitudinalTransverse

PTC

Cystic PTC

Cystic PTC - UGFNA

4cm Left Cystic Nodule FNA - PTC

Invasion of Strap Muscle

Invasion of Carotid Sheath

Invasion of Larynx

Cystic Papillary

carcinoma

invading the

Larynx. Note

the classic

intra-cystic

Cauliflower

appearance.

Taller than wide

Kim AJR 2002; Cappelli Clin Endocrinol 2005; Moon Radiology 2008

Nodule is taller than wide on

the transverse view

What About Intranodular Flow?

B-Mode Power Doppler

NO LONGER CONSIDERED AN INDEPENDENT

RISK FACTOR WHEN DECIDING ON FNA

PTC – lack of Doppler

Don’t be re-assured by lack of

Doppler flow !

US Prediction of Thyroid Cancer

Sensitivity Specificity

Microcalcifications 45% 85%Absence of halo 66% 46%Poorly defined margins 64% 77%Hypoechoic 80% 45%Increased Doppler flow 67% 81%Taller than Wide 48% 92%MicroCa2+ + irreg margin 30% 95%MicroCa2+ + hypoechoic 28% 95%Solid + hypoechoic 73% 69%

Brkljacic J Clin Ultrasound 1994; Takashima J Clin Ultrasound 1994; Rago Euro J Endorinol 1998; Cerbone Horm Res 1999; Leenhardt J Clin Endocrinol Metab 1999; Kim AJR 2002; Papini J Clin Endocrinol Metab 2002; Cappelli Clin Endocrinol 2006

Interobserver variability of US features

Kappa values

Agreement

<0.2 slight

0.21-0.4 fair

0.41-0.6moderate

0.61-0.8 substantial

>0.8 ~perfect!

Moon Radiology 2008 247:762; Choi Thyroid 2010 20:167

Factors Contributing to

Variability of US Reporting

US machine properties

Probe frequency

Gain, power output

Use of harmonics or post image acquisition software e.g.

smoothing

Image interpretation

Static vs. real time

Use of video

Patient factors

Depth of nodule

US Pattern Recognition

While individual

features are suggestive,

combining features and

pattern recognition are

the keys to US risk

stratification of thyroid

nodules

TIRADS-Horvath 2009

Category US PATTERN MALIGNANCY

RISK %

TIRADS 1 Normal thyroid gland 0

TIRADS 2 Cyst with or without comet tail

Spongiform

Mixed cystic/solid with solid portion mixed

0

TIRADS 3 Hashi’s pseudonodule <5

TIRADS 4 5-80

4A Solid or mixed hyper/isoechoic with thin

capsule

5-10

4B Hypoechoic with irreg margins

Hyper/iso/hypo with thick capsule

10-80

TIRADS 5 Hypo/Iso nonencapsulated with microcalcs >80

Horvath J Clin Endocrinol Metab 2009;90:1748

TIRADS-Kwak 2011Category Number of suspicious US

features

CANCER

RISK %

TIRADS 3 NONE 1.7

TIRADS 4A 1 3

TIRADS 4B 2 10

TIRADS 4C 3-4 44-73

TIRADS 5 5 88

Suspicious US features: solid

marked hypoechogenicity, hypoechogenicity

microlobulated or irregular margins

microcalcifications

taller than wide shape

Kwak Radiology 2011;260:892

Kwak 2011 features – A – hypoechoic, B – microca, C – Markedely hypoechoic D – Irregular Margins

Adapted TI-RADS based on Russ 2011.

Russ, Leboulleux, Leenhardt, Hegedus Eur Thyroid J. 2014 Sep;3(3):154-63

Russ 2013

Adapted TI-RADS based on Russ 2011.

Russ, Leboulleux, Leenhardt, Hegedus Eur Thyroid J. 2014 Sep;3(3):154-63

TIRADS - Interobserver

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

TIRADS 2-5 TIRADS 4-5

Ka

pp

a v

alu

es

Cheng et al. Russ et al.

Russ, Leboulleux, Leenhardt, Hegedus Eur Thyroid J. 2014 Sep;3(3):154-63

Russ 2013 95.7% Sensitivity

61% Specificity

High

Suspicion

70-90%

Intermediate

Suspicion

10-20%

Low

Suspicion

5-10%

Very low

Suspicion

<3%

Benign

<1%

ATA 2015: Nodule Sonographic Pattern Risk of Malignancy

Haugen et al. Thyroid; October 2015

PTC foll variantBenign Hürthle cell

adenoma

Follicular thyroid cancer

Isoechoic/Hyperechoic and Solid

~20% of all cancers are Iso/hyperechoic:

predominantly follicular/ Hürthle

Hyperplastic noduleHyperplastic nodule

Sonographic Features of Follicular Variant Papillary

Cancer versus Conventional Papillary Cancer

FEATURE FOLLICULAR

VARIANT (n=44)

CONVENTIONAL

PAPILLARY (n=74)

Size (mean) 17 mm 10.5 mm

Ovoid to round shape 95% 73%

Isoechoic 52% 8%

Halo 25% 3%

Taller than Wide 5% 22%

Marked Hypoechogenicity 5% 38%

Microcalcifications 3% 24%

FNAB Dx of Papillary CA 28% 56%

FNAB Indeterminate 46% 19%

Kim DS et al. J Ultrasound Med 2009, 28:1685

R8 US Pattern and suggested FNA cutoffs

Sonographic

Pattern

Estimated

malignancy

risk

FNA size

cutoff

Strength

of rec

Quality of

evidence

High suspicion >70-90% > 1 cm Strong Moderate

Intermediate

suspicion

10-20% > 1 cm Strong Low

Low suspicion 5-10% > 1.5 cm Weak Low

Very low

suspicion

< 3% > 2 cm Weak Moderate

One option is surveillance

Benign < 1% No biopsy Strong Moderate

FNA is not recommended for nodules

that do not meet the above criteria,

including all nodules < 1 cm

Strong Moderate

Haugen et al. Thyroid; January 2016

Micronodules Concerning for PTC

Sonographic appearance of micro PTC and risk

50% 14% 2%

30% <5%

Ito World J Surg 2016;40:523–528; Miyauchi World J Surg 2016 40:516–522

Sonographic

PatternStrength

of rec

Quality of

evidence

High

suspicionRepeat US and US FNA

within 12 months

Strong Moderate

Intermediate/

Low

suspicion

Repeat US at 12-24m

If growth or new suspicious

US feature, repeat FNA OR

continued observation

Weak Low

Very low

suspicion

Utility of surveillance US and

assessment of nodule growth as

an indicator for repeat FNA is not

known. If repeated, US should at

> 24 months

Weak Low

IF 2nd US FNA done with benign cytology, US

surveillance for continued risk of malignancy is

no longer indicated

Strong Moderate

R23 Follow-up of nodules with benign cytology

Haugen et al. Thyroid; January 2016

Stephanie Lee - AACE 2016 AM

Slide from Stephanie Lee - AACE 2016 AM

Other Patterns

hyperechoic, microcalcs

eggshell calc

isoechoic, coarse calc

isoechoic, margin

lobulated smooth

ATA May Have Limitations in

Thyroid Nodule Classification

Compared with TIRADS

Yoon et a. Radiology 2016; 278: 917-924

-Comparison ATA 2015 with TIRADS 2011

-3.4% of 1,293 nodules without ATA Classification

-18.2% of “not specified” ATA nodules malignant

ACR TI-RADS 2017

Tessler et al; J ACR 2017

Point based system

Composition

Echogenicity

Shape

Margins

Echogenic Foci

“Leave no nodule behind”

Tessler et al; J ACR 2017

Cystic or almost completely cystic

almost universally benign

Russ G. Ulttasonography 2016; 35: 25-38

Moon WJ Radiology 2008; 247: 762-770

Lee et al. Thyroid 2009; 19(4): 341-346

Spongiform composition – 0 points

Colloid cyst

Mixed Cystic-Solid -- 2 points

(w/ no suspicious features)

No FNA

ACR TI-RADS System FNA

Indications TIRADS 3-5

Consider FNA

2016 AACE Nodule Guidelines

Benign - <1% ROM

Intermediate – 10-15% ROM

Suspicious – 50-90% ROM

Sonographic

Pattern

Estimated

malignancy

risk

FNA

size

cutoff

AACE

Level of

Evidence

AACE

Strength

of Rec

High

Risk US

50-90% > 1 cm 2 A

Intermediate

Risk US

5-15% > 2 cm 2 A

Low Risk US <1% > 2 cm

or

growing

2 A

US Risk and suggested FNA cutoffs

Conclusions

Ultrasound is the cornerstone of thyroid nodule

evaluation and always includes evaluation of the

regional lymph nodes

Pattern recognition is more valuable than

individual suspicious features

FNA decision making is based on the risk

stratification of the nodule pattern