Thyroid UK

Thy3a meaning?

Hi i am really confused and wondering if anyone can help....i have had a FNA after ultrasound scan which revealed 1inch lump in diameter, my doctor has received a letter advising inconclusive which i have been advised is common, they sent a letter saying i was thy3a does anyone know what this means?? my doctor did not know googled something and said am sure its fine!

2 Replies

Hi I think it means you need further treatment and to see a surgeon. However, normally for any thyroid nodule, you should automatically have a fine needle biopsy, radiologist under an ultra sound. This is routine, then any thing can be decided on that result.

I hope that helps. Good to have found it.

Best wishes,



As you will see, this means 'neoplasm possible-atypia/non-diagnostic' In other words, they see that something is growing, and has some unusual cells, but they are unable to make a determination of what kind of growth it is. If it were regarded as suspicious, it would be in the Thy4 category, not the Thy3.

The categories are as follows: This information comes from:

Thy1 - the specimen was not good enough for various reasons, to form any conclusion (Blood, not enough cells, etc.)

Thy2 - non-neoplastic. Completely normal thyroid tissue or cystic fluid, or other forms of benign non-cancerous overgrowth.

Thy3 - a sample has evidence of unusual cells but it cannot be determined what kind of cells, most probably benign. If it is follicular it would be Thy3f but where it is not identified it is classed as Ty3a - atypical.

Thy4 - suspected malignancy but cannot be certain.

Thy5 - Malignant.

As you can see from this although it is Thy3 it is actually only one stage from perfectly normal, because Thy1 refers to a bad sample.

If they have not been able to determine what kind of nodule it is, then further investigation would be needed. The good news is that most turn out to be nothing sinister.

All the same, in your position I would not be inclined to leave it at that. If your doctor has any doubts about his understanding of your condition, then he should be making sure what the next step ought to be.

It may be that you need to be monitored to see if it grows, and if it does, then a repeat of the FNA to see if any changes have occurred.

Marie XX


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