TIRADS III nodules on ultrasound of thyroid

Abstract ID -1213

Literature Review• Thyroid nodules are common and ultrasound is the modality

of choice to characterize them.• TIRADS is used in our center to stratify cancer risk in thyroid

nodules.• Positive predictive value for malignancy in TIRADS 3 nodules

in literature is 1.7 – 7.3%. (ref: 1, 2)

• We aimed to audit the number of TIRADS 3 nodules which turned out to be malignant and have a closer look at their ultrasound features.

Korean J Radiol; 14:110-1171

Radiology; 260:892-8992

Objectives1. To assess the number of TIRADS 3 nodules

which were malignant on FNAC or histopathology

2. To assess the imaging features of TIRADS 3 nodules which was malignant on histopathology and compare them with benign thyroid nodules

Methodology

Total no. of USG thyroids = 670

TIRADS III nodules n = 102

With HPE= 51

Retrospective study• USG thyroids done in our institution over a period of 3

months (Jan – March 2014) were assessed by obtaining data from the PACS and clinical workstation

• Of these, TIRADS III lesions were studied

Inclusion criteria• Patients with TIRADS 3 thyroid nodules diagnosed

on USG of thyroid USG TIRADS 3:

well defined oval solid of mixed isoechoic nodules• Diagnostic FNAC or surgical histopathology at CMC,

Vellore

Exclusion criteria• Thyroid nodules of other categories: TIRADS 2,

TIRADS 4, TIRADS 5• Inadequate thyroid FNAC with no surgical

histopathology

Colloid nodules - TIRADS 2 TIRADS 4 and 5

Methodology contd…• Following additional features were assessed in these nodules:- Heterogeneous echotexture- Nodule in nodule sign: Subtle hypoechoic area within a

predominantly isoechoic oval nodule- Hypoechoic internal septa sign: Hypoechoic ill-defined

branching lines within the nodule- Thick non uniform halo

• TIRADS 3 nodules were compared with FNAC and histopathology diagnosis.

Statistical Analysis• Analysis was done using SPSS version 16.0 • Categorical variables were analysed using Pearson

chi-square test

• Continuous variables were analysed using independent sample t-test

Results

• Total number of nodules= 51• Age: 39.78 +/- 12.53 ( age range of 19- 72 years)• Male to female ratio: 11:40

• Total number of nodules with HPE/FNAC =51• Total number of cases with FNAC=41• Total number of cases with surgical HPE= 18

Malignancy in TIRADS III nodules• Number of benign nodules = 40• Number of malignant nodules = 11

• Incidence of malignant nodules among TIRADS 3 lesions on ultrasound thyroid is 11/ 102 = 11%

Total no= 51 No Percentage %Follicular variant papillary carcinoma thyroid

11 61

Adenomatous hyperplasia 04 22

Follicular adenoma 02 11

No follicular hyperplasia 01 6

Surgical Histopathology: ( n=18)

All malignant nodules (n=11) were encapsulated variety of follicular variant of papillary carcinoma thyroid.

Bethesda classification cytology (FNAC):

Bethesda class

No. of cases

%

I 01 1.9

II 34 66.6

III 03 5.8

IV 03 5.8

V 00 00

VI 00 00class I

class IIclass III

class IVclass V

class VI

0

5

10

15

20

25

30

35

class I = 1

class II= 34

class III= 3class IV =3

class V; 0class VI; 0

n=41

n=41

Results contd..

• Male patients has higher risk of TIRADS 3 nodule being malignant ( chi square= 4.73 ; p= 0.03)

• There was a positive trend towards malignancy when nodules had heterogeneous echotexture and hypoechoic internal septa sign

• Cystic change in the nodule tended to predict benign thyroid nodule (p = 0.06)

Results contd..• Combined criteria of “nodule within nodule”

appearance and hypoechoic internal septa” best predicted malignancy in the TIRADS 3 nodules. • Chi square= 29.5; p = 0.000

Diagnostic significance of combined criteriaDiagnostic performanceSensitivity 100%

Specificity 90.9%

Positive predictive value 63.6%

Negative predictive value 100%

ROC analysis: Area under the curve= 0.818 (0.64-0.99)

24 year old female patient follicular variant of papillary carcinoma

Well defined, oval, solid, isoechoic, heterogenous nodule with thick non uniform halo (arrows) and positive hypoechoic internal septa sign.

Eccentric hypoechoic focus within a isoechoic well defined nodule - positive nodule in nodule sign

37 year old female -Case of follicular variant of papillary carcinoma

Positive hypoechoic internal septae sign in another patients with FVPTC

24 year old female with benign follicular nodule

Well defined isoechoic nodule with cystic degeneration

48 year old male with histopathology diagnosis of follicular adenoma

Well defined homogenous isoechoic nodule with few cystic spaces -negative for nodule within nodule sign and hypoechoic internal septatae

Well defined isoechic hetrogenous nodule -positive for nodule within nodule sign -positive for hypoechoic internal septae sign-positive thick non uniform halo

54 year old man with histopathology diagnosis of follicular variant of papillary carcinoma

Conclusions• Encapsulated variety of follicular variant of papillary

carcinoma thyroid mimics benign thyroid nodules and usually reported as TIRADS 3 nodules

• The incidence of follicular variant of papillary carcinoma among TIRADS 3 lesions is 11% in our series

• Use of combined criteria of nodule in nodule sign and hypoechoic internal sepate sign will help identify malignancy in TIRADS 3 nodules.