PAPILLON COURSE on THYROID ULTRASOUND
Case of the Month
December 2021 - case 2 - evaluation
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Summary and comments
49 participants have answered the questions.
1. How to classify the nodule?
Distribution of answers
Choice Dominantly cystic, with iso/hyperechoic solid part Dominantly cystic with minimally/moderately hypoechoic solid part Dominantly cystic with deeply hypoechoic solid part
Expert comment
Before aspiration, the echogenicity of the solid part is darker than the extranodular tissue but lighter than the strap muscle, i.e., the nodule would be minimally/moderately hypoechoic.
After the aspiration, the solid part became significantly darker. I've measured the histogram value of the nodule at 0:46 sec. The mean value of the nodule was 37.1 while that of the strap muscle running ventral to the thyroid was either 46.6 or 63.2, histogram value of the muscle fiber with low adipose content or histogram value of the entire strap muscle. Both values are higher than that of the nodule, so the echogenicity of the nodule should be considered as deeply hypoechoic after aspiration.Neither protocol deals with the issue whether the echogenicity of a cyst should be defined before or after the removal of the cystic content. I prefer to judge after the removal. So, I would regard the nodule as deeply hypoechoic, but naturally the second answer is also acceptable.
2. How to judge the shape of the nodule?
Distribution of answers
Choice The nodule obviously shows pathological form of taller-than-wide shape. The shape of the nodule should not be considered as nonparallel because the shape of a lesion is preferred to judge after removal of cystic content. The question cannot be clearly answered. Macrocalcifications
Expert comment
The situation is similar to the former regarding the lack of literature data. It is quite different when a nonparallel orientation is observed in a solid nodule than when it is detected in a dominantly cystic one. For the former, we can hypothesize that a more aggressive growth of a tumor causes nonparallel orientation, however, this hypothesis makes no sense in relation to cystic fluid.
I would prefer the second answer, i.e., I would not consider the nodule as showing nonparallel orientation, however based on the former considerations, all three answers are acceptable.
3. How to judge the borders of the nodule?
Distribution of answers
Choice The borders are sharp and regular because we should judge the borders of a cystic nodule before aspiration of cystic fluid. The borders are irregular, lobulated because we should judge the borders after the aspiration of the cystic content. The question cannot be answered.
Expert comment
I think that the first answer is the correct one.
4. Which hyperechoic figures does the nodule have?
Distribution of answers
Choice Microcalcifications Comet-tail artifacts Back wall cystic figures Microcalcifications and comet-tail artifacts Microcalcifications and back wall cystic figures Comet-tail artifacts and back wall cystic figures All three
Expert comment
I agree with the majority, the nodule has comet-tail artifacts (see at 0:46 at the ventromedial part of the nodule or at 0:50 in the central part of the lesion) and numerous back wall figures. Although, there are some punctate echogenic figures within the nodule, their coexistence with linear forms stands for connective tissue or back wall figure, in this case for the latter.
5. How to classify the nodule according to EU-TIRADS?
Distribution of answers
Choice EU-TIRADS 2 EU-TIRADS 3 EU-TIRADS 4 EU-TIRADS 5
Expert comment
What is clear is that the nodule cannot be TIRADS 2 because only pure and spongiform cysts can be included in this group.
There are two questions, one is whether someone has found a suspicious sign (nonparallel orientation, microcalcification, and deep hypoechogenicity). If yes, the nodule should be regarded as TIRADS.
If not, the classification depends on the judgement of the echogenicity of the solid part. If it would be considered as iso/hyperechoic then the nodule must be a TIRADS 3 lesion, if this would be regarded as minimally/moderately hypoechoic, then this is a TIRADS 4 lesion. 41 colleagues correctly applied the EU-TIRADS rules.
