1. TIRADS III nodules on ultrasound of thyroid
Abstract ID -1213

2. 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:
Radiology; 260:

3. Objectives
To assess the number of TIRADS 3 nodules which were malignant on FNAC or histopathology
To assess the imaging features of TIRADS 3 nodules which was malignant on histopathology and compare them with benign thyroid nodules

4. Methodology 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
Total no. of USG thyroids = 670
TIRADS III nodules n = 102
With HPE= 51

5. 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

6. Exclusion criteria
Thyroid nodules of other categories: TIRADS 2, TIRADS 4, TIRADS 5
Inadequate thyroid FNAC with no surgical histopathology
solid component
markedly hypoechoic nodule
microlobulations or irregular margins
microcalcifications
taller-than-wider shape
TIRADS 4a - one suspicious feature
• TIRADS 4b - two suspicious features
• TIRADS 4c suspicious features
• TIRADS 5 - all five suspicious features
TIRADS 4 and 5
Colloid nodules - TIRADS 2

7. 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.

8. 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

9. Results Total number of nodules= 51
Age: / ( age range of 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

10. 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%

11. Surgical Histopathology: ( n=18)
Total no= 51 No
Percentage %
Follicular variant papillary carcinoma thyroid 11 61
Adenomatous hyperplasia 04 22
Follicular adenoma 02
No follicular hyperplasia 01 6
All malignant nodules (n=11) were encapsulated variety of follicular variant of papillary carcinoma thyroid.

12. Bethesda classification cytology (FNAC):
No. of cases % I 01
1.9 II 34
66.6
III 03
5.8 IV V 00 VI

13. 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)

14. Results contd.. Diagnostic significance of combined criteria
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 criteria
Diagnostic performance
Sensitivity
100%
Specificity
90.9%
Positive predictive value
63.6%
Negative predictive value
ROC analysis: Area under the curve= ( )

15. 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.

16. 37 year old female -Case of follicular variant of papillary carcinoma
Eccentric hypoechoic focus within a isoechoic well defined nodule - positive nodule in nodule sign

17. Positive hypoechoic internal septae sign in another patients with FVPTC

18. 24 year old female with benign follicular nodule
Well defined isoechoic nodule with cystic degeneration

19. 48 year old male with histopathology diagnosis of follicular adenoma
54 year old man with histopathology diagnosis of follicular variant of papillary carcinoma
48 year old male with histopathology diagnosis of follicular adenoma
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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

20. 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.