Choice	%	No
Iso/hyperechoic	17.5	11
Minimally/moderately hypoechoic	79.4	50
Deeply hypoechoic	3.2	2

Expert comment

I would consider the nodule as a minimally/moderately hypoechoic lesion. Note that the nodule is darker than the extranodular parenchyma but lighter than the muscle running ventral to the thyroid.

Distribution of answers

Choice	%	No
Microcalcifications	1.6	1
Back wall cystic figures	47.6	30
Comet tail artifacts	4.8	3
None of them	46.0	29

Expert comment

I would consider the pale echogenic lines and granules as the normal backbone of the thyroid tissue. These became visible because the nodule got darker. So, I would prefer the last answer. Nevertheless, I cannot regret the second answer. The micro- and normofollicles surround the colloid, the consistency of which is between fluid and solid, therefore can present back wall figures. I could not find any macrocalcifications within the nodule.

Distribution of answers

Choice	%	No
EU-TIRADS 3	17.5	11
EU-TIRADS 4	73.0	46
EU-TIRADS 5	9.5	6

Expert comment

Taking the answers to the previous questions, most answers were consistent.

Distribution of answers

Choice	%	No
Yes	98.4	62
No	1.6	1

Expert comment

A nodule larger than 2 cm in diameter should be evaluated by FNA according to the EU-TIRADS except for spongiform and pure cysts.

5. Which statement is the most appropriate?

Distribution of answers

Choice	%	No
There is a greater than 50% chance that the nodule will prove to be a hyperplastic nodule	12.7	8
There is a greater than 90% chance that the nodule will prove to be a hyperplastic nodule	4.8	3
There is a greater than 50% chance that the nodule will prove to be a follicular adenoma	42.9	27
There is a greater than 90% chance that the nodule will prove to be a follicular adenoma	20.6	13
There is a greater than 50% chance that the nodule will prove to be a papillary or follicular cancer	14.3	9
There is a greater than 90% chance that the nodule will prove to be a papillary or follicular cancer	4.8	3

Expert comment

Such nodules, i.e. a homogeneous solitary large nodule having halo is almost always a follicular tumor, the chance is surely greater than 90%.

Distribution of answers

Choice	%	No
According to the protocol, no further investigation is necessary. The patient should be operated on. Lobectomy is the treatment of choice	61.9	39
According to the protocol, no further investigation is necessary. The patient should be operated on. Total thyroidectomy is the treatment of choice	28.6	18
Follow-up examination in 6 to 12 months. If the nodule would increase in size, then surgery	7.9	5
Scintigraphy	1.6	1

Expert comment

If we follow the protocol, we should perform lobectomy.

However, I honestly admit, I did not follow the protocol in this particular case. The ultrasound presentation of the whole thyroid suggested autonomously functioning adenoma. The dimensions of the intact left lobe were 12x8x29 mm, width, depth, length, respectively, i.e. the volume of the lobe was 1.46 mL, substantially lower compared with an average size of a lobe. OK, the TSH was not suppressed, nevertheless, we cannot exclude the possibility that the 1.20 mIU/L TSH-level already indicates a decreased level in that patient. It is also worth taking into account that more than half of solitary autonomously functioning nodules prove follicular tumor (almost always follicular adenoma) on histopathology. So, I indicated scintigraphy which disclosed autonomously functioning adenoma.

When judging the answers, we must take several considerations into account. First, the presence of iodine deficiency. Ten years ago, Hungary was a mildly iodine-deficient area and some consequences of iodine-defiency last for decades after the restoration of iodine intake; this is especially true for nodule' formation and the increased risk of autonomy. In countries which were always iodine-replete, the risk of autonomy is significantly lower in a case like the one I just presented. Most authors of the guidelines are from countries which were always iodine-replete, therefore, not all suggestions of these protocols are equally valid in iodine-deficient countries. E.g. the risk of thyroid cancer in cytologically diagnosed follicular tumors, has been put at 25-30% by the Bethesda study. This risk is only 3 to 5% in Hungary.

One more comment to be clear. In most cases of cytologically diagnosed follicular tumors in a euthyroid patient, the indication of surgery is evident. The exceptions when scintigraphy is worth considering are those cases in which the contralateral lobe is decreased in size and/or there are cytological signs of hyperfunction.