First examination (first row of images)

Clinical presentation: A 27-yr-old woman was referred for evaluation of thyroid nodule which has been discovered for 6 months by the patient herself.

Palpation: an elastic nodule in the right lobe.

Laboratory test: TSH 0.88 mIU/L.

Ultrasonography. The thyroid was echonormal. There was a dominantly solid nodule in the right lobe. The nodule was heterogenous with a dominantly echonormal echogenicity. The lesion presented perinodular blood flow. The dimensions of the nodule were 24x17x31 mm (width, depth, length, respectively)

Cytology was non-diagnostic (cystic fluid only).

Suggestion: repeat FNA in three months.

Second examination 2 years later (second row of images)

Clinical presentation: The woman came to follow-up evaluation only two years after the initial examination.

Palpation: an elastic nodule in the right lobe.

Laboratory test: TSH 0.91 mIU/L.

Ultrasonography. The pattern remained unchanged. The dimensions of the nodule have been increased to 30x21x42 mm (width, depth, length, respectively). The increase was mainly explained by the increase in the cystic content.

Cytology resulted papillary carcinoma.

Histopathology disclosed a follicular variant of papillary carcinoma with a largest diameter of 25 mm. Benign hyperplasia was found in other parts of the thyroid.

Comment.

1. The nodule was clearly a dominantly solid nodule at the first examination while the categorization is not evident on the follow-up because the proportion of cystic and solid areas are nearly equal (unfortunately the video is not decisive because we focused on the solid area).
   
2. The solid part is heterogeneous, the dominant pattern is echonormal. Depending on the different definitions, this nodule is categorized either among TIRADS 3 or TIRADS 4, Korean and European TIRADS, respectively. The former system relies on the dominant pattern of the nodule, while the latter says that if there are hypoechoic portions, the lesion should be classified in TIRADS 4 group.