thyroid frozens

[pathbot]

We get a lot of thyroid frozens on lobectomy specimens performed at my institution. These tend to be done regardless of FNA result (many cases benign), and in some cases no FNA may even have been done. This raises question of cost effectiveness, but we have been happy to oblige given the few cases we may be helpful and save an additional surgery.

The result of this is that thyroids have become are biggest frozen discordance. We have a handful of cases in which frozen showed no obvious malignancy but the final dx is papillary. The most common scenarios include a micropapillary picked up on additional permanent sections (fine, it happens), or a follicular variant of papillary which was just not able to be called by frozen.

My question to the group: given the entity now known as "non-invasive follicular neoplasm with papillary-like nuclear features", does this mean that we should really not be calling any follicular lesion papillary on frozen sections. My impression is that any pure follicular lesion should at least be deferred to permanents, because the entire capsule or periphery should be looked at before determining malignancy. Therefore, even if touch preps show papillary cytology, malignancy should not be diagnosed until invasion is seen.

I guess my approach now is to only call papillary on frozen if I see definitive papillary architecture.

Any thoughts from the group?

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[SEpathguy]

We get a decent number of thyroid lobes for frozen where I work and that's my understanding of how to deal with that new entity also. I just call anything with a follicular pattern "follicular lesion, defer to permanent" - which is the large majority of cases. In the rare instance that I see obvious papillary cytologic features but a follicular pattern, I verbally tell the surgeon it could be the new non-invasive follicular neoplasm with papillary like nuclear features, but I still bottom line it as follicular lesion, defer to permanent. When I have papillary architecture I look for papillary cytology. In my mind it makes frozens on thyroid lobes easier (but also probably makes them even more useless clinically than they were before). Seems like it would be more reasonable for the surgeons to just base the operative management on the FNA results and not do thyroid frozens at all.

 

[Euchromatin]

Seems like it would be more reasonable for the surgeons to just base the operative management on the FNA results and not do thyroid frozens at all.

This is essentially what the current literature on this topic says. It isn't entirely unreasonable to confirm a diagnosis of conventional/classic PTC on frozen if the FNA was called "suspicious for PTC/malignancy," but otherwise thyroid frozens are a complete waste of time and unhelpful in directing surgical management. Also, depending on the quality/technique used, the freezing artifact introduced may negatively impact the quality of the final/permanent H&E sections, particularly in regards to evaluation of papillary nuclear features.

Depending upon how much free time your group has available to do pointless frozens and how amenable your surgeons are to persuasion, it might be worthwhile to pull some references and try and "provide education"/talk them out of routine use. The current ATA guidelines don't make a particularly strong statement: "Intraoperative evaluation, with or without frozen section, can occasionally confirm malignancy at the time of lobectomy allowing for conversion to total thyroidectomy if indicated. Frozen section is most helpful if the histopathologic diagnosis is classic PTC, whereas its impact is low in follicular variant of PTC and FTC." However, a lot of the references that are provided in the ATA guidelines are more explicit in arguing against thyroid frozens in current clinical practice.

Luckily, none of the higher volume thyroid surgeons in my practice request frozens. We just occasionally have to talk a lower volume surgeon at one of our smaller, outlying hospitals out of asking for one.

 

[deleted314957]

Agree with Euchromatin. This had been pretty standard at my place about
4 yrs ago.