PAPILLON COURSE on THYROID ULTRASOUND
Case of the Month
October 2024 - case 1 (1214) - evaluation
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Summary and comments
48 colleagues have sent a reply.
1. How would you consider Nodule 1?
Distribution of answers
20 Dominantly cystic with iso/hyperechoic solid part.
22 Dominantly cystic with minimally/moderately hypoechoic solid part.
3 Dominantly solid with iso/hyperechoic solid part.
3 Dominantly solid with minimally/moderately hypoechoic solid part.
Expert comment
The ratio of solid portion to cystic areas is very close 1, therefore I can accept both that that the nodule is dominantly cystic and that the nodule is dominantly solid. The echogenicity is again very difficult to judge because it is at the border of isoechoic and minimally/moderately hypoechoic. So, again I can accept both answers.
2. How would you consider Nodule 2?
Distribution of answers
3 Heterogeneous, dominantly iso/hyperechoic.
24 Heterogeneous, dominantly minimally/moderately hypoechoic.
21 Heterogeneous, dominantly very hypoechoic.
Expert comment
It is evident that the dominant part of the nodule is hypoechoic. The reference tissue which discriminates between deeply and minimally hypoechoic nodules is that part of the strap muscle which has low adipose tissue content. The dominant, hypoechoic area has islets which are deeply hypoechoic, e.g., the ventral and medial small portions at 0:30 in the video. On the other hand, both the dominant and the average gray-scale levels correspond to minimally/moderately nodule. In contrast with a heterogeneous nodule, we have no instructions on how to deal with this problem, i.e., how to categorize hypoechoic nodules or hypoechoic parts of the nodule which have both minimally and deeply hypoechoic areas. I guess that in this case the dominant part should be taken into account, therefore, I would regard this nodule as a heterogeneous, dominantly minimally/moderately hypoechoic one.
3. How would you consider Nodule 3?
Distribution of answers
22 Mixed, dominantly solid, the solid part is heterogeneous and dominantly iso/hyperechoic.
4 Mixed, dominantly solid, the solid part is heterogeneous and dominantly minimally/moderately hypoechoic.
16 Mixed, dominantly solid, the solid part is iso/hyperechoic.
3 Mixed, dominantly solid, the solid part is minimally/moderately hypoechoic.
2 Solid, heterogeneous and dominantly iso/hyperechoic.
1 Solid, heterogeneous and dominantly minimally/moderately hypoechoic.
Expert comment
Whether the nodule should be regarded as dominantly solid or solid depends on the judgement whether the solid portion exceeds 5% or not. Practically this has no relevance in the EU-TIRADS while this judgement can have relevance in the ATA, ACR and Korean TIRADS. I estimate that the area of cystic parts is between 5 and 10%. So, I would consider the nodule rather mixed, dominantly solid than simply solid.
Significantly more important is the judgement on echogenicity. I agree with those how stated that this is a heterogeneous, dominantly iso/hyperechoic nodule. It seems to be evident that the proportion of the iso/hyperechoic parts exceeds that of minimally/moderately ones. The other and similarly important issue is whether the solid part should be regarded as heterogeneous or not. According to the rule of the ETA, it should be considered as heterogeneous because the minority minimally hypoechoic part exceeds 5 mm. I prefer another definition, i.e., the minority party should exceed 10% of the entire solid part or should be larger than 10 mm. According to both definitions, the nodule should be regarded as heterogeneous.
Let's notice the difference between the 2 judgements: if the nodule is regarded as iso/hyperechoic, then this should be considered as a TIRADS 3 lesion. However, if we the nodule is considered as dominantly iso/hyperechoic (it means that the nodule has hypoechoic parts as well), then the nodule is an EU-TIRADS 4 lesion.
4. How would you consider Nodule 4?
Distribution of answers
2 Heterogeneous, dominantly iso/hyperechoic.
44 Homogeneous iso/hyperechoic.
2 Homogeneous minimally/moderately hypoechoic.
Expert comment
I agree with most colleagues. The nodule's echogenicity is identical with the extranodular part, so it is iso/hyperechoic. We can reveal very tiny hypoechoic areas within, however, the presence of such very tiny islets corresponds to normal inhomogeneity.
