Section 2 The nodular goiter

Part 7 Extrathyroidal spread


The extrathyroidal extension (ETE) is one of the two ultrasound characteristics which can be compared to the reality, to the histological finding. It means that we have a biological standard. The presence of ETE is a clear evidence that the lesion is malignant. The problem is that the thyroid has no capsule and therefore not infrequently it is very difficult to judge the borders of the organ. Sono-histological comparison revealed the limits of our knowledge. In the everyday practice, ETE is recognized on US examination in around 50% of cases and the positive predictive value is again around 50%. The latter means that in half of those cases when an experienced investigator says the lesion extends beyond the thyroid gland, there is in fact no ETE.

So, it is strongly advised to be restrained and in uncertain cases only raising suspicion is acceptable.

This section is composed of the usual parts.

  1. Introductory course briefly gives an overview of extrathyroidal spread, discusses the occurrence of ETE in various forms of thyroid carcinomas and the role of ETE in different TIRADS.
  2. Manual on ETE serves as a guidance for the reader. The manual can be downloaded in pdf format.
  3. In courses we try to give an approach to differential diagnostic.
  4. Case study is composed of dozens of cases most of them presents beside 5 to 15 ultrasound images ultrasound videos, as well.
  5. Videolibrary serves the goal of testing the skills by analyzing videos.

As in other chapters, I emphasize that I would be very thankful for any comments and for any remarks on scientific failures or linguistic errors. Thank you for your comments and remarks in advance!

Case study of the topic

A 48-year-old woman was referred for aspiration cytology. The patient has been known harboring a nodule for two years. The lesion in the middle part presented all three possible signs on which extrathyroidal extension can be suspected, i.e. the contours were abutting, and bulging and the capsule of the lobe was not continuous. Cytology resulted in benign cystic-colloid goiter.
The issue is that the positive predictive value of ultrasound features is relatively poor regarding extrathyroidal extension.