The approach to the Thyroid Nodule.

While studying today, my study partner and I came a cross a descrepancy between MTB, UW, Absite Comprehensive Review and Conrad Fischer's disease deck. 2/4 sources say  to do an FNA first while the other 2/4 say to do thyroid panel first. Confounding. Arguemtns for both:

1. MTB and Absite Review: FNA first because it is the most accurate diagnostic modality
2. UW and Disease Deck: thyroid panel first to determine if the nodule is or is not functional and US  to rule out cystic lesion; then do FNA "of all solid lesions that are non-functional and cysts with pathologic features on US".
And here's a confounder for ya: MTB and Disease Deck were written by the same author. Go figure! Looks like this needs a journal review. So, look forward to an addendum.

Addendum:
So, with a solitary thyroid nodule, you want to rule out cancer. Steps to take:
1. biochemical assesment --> TSH, T3/T4: would you do a scintigraphy?
2. thyroid US --> characteristics that would suggest malignancy
*3. FNA: the most important

The article I looked at [link below] went on to say that an FNA must also be done. You can argue about the bearings of the findings on US [findings which are subjective, they are subject to the skill level of the US technician or what have you]: as methods improve the sensitivity and specificity of the test increases, however utility as a guide for biopsy outweighs its value as a sole diagnostic technique. The only way to definitively diagnose a malignancy is by doing the FNA and looking for the cells implicating malignancy.

So why bother doing a thyroid US? Ultra sound can be used to guide the FNA and has been found in some situations to be better guide than palpation. But for the purposes of diagnoses alone it, in my opinion doesn't seem diagnostic. The findings of the FNA are what will determine management as was addressed in the article.

The other item was the scintigraphy; at what point in patient management does one get carried out? Although this imaging is usually not done anymore, it can determine if a nodule is hot, cold or warm. Hot tends to rarely be malignant while a small percentage of cold and warm have that propensity. The third link I have listed talks about the re-emergence of this modality with mangement for multi-nodular goiter as opposed to solitary.

My second source sheds more light on when to do what. It's the "Endocrinology Board Review Manual"- from the horse's mouth. Here is a screen shot of the item- again, the source is the second link: click on image to enlarge.

http://www.ncbi.nlm.nih.gov/pubmed/18305054

http://www.turner-white.com/pdf/brm_Endo_V6P6.pdf
http://www.ncbi.nlm.nih.gov/pubmed/18847633