Molecular trumps morphology?

[levels x3]

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Not personally my case, but my group recently made the diagnosis of follicular lymphoma, grade 3A. Due to the circumstances of the case, this diagnosis was based upon H&E and IHC alone. Flow could not be done. The morphology is classic, slam-dunk, 99 out of 100 hematopathologists would agree, take a picture and put it in a textbook classic (I'm not a hemepath, though we do have one here who agrees this is classic). Patient and material went to a nearby academic center for consultation where they decided to throw everything including the molecular kitchen sink at it. Well...FISH negative and B-cell gene rearrangement PCR reported as polyclonal. On the basis of these results, though they describe morphologically classic follicular lymphoma, they state that you can't call it lymphoma.

When I left training, all of 2.5 years ago, we never would have considered doing PCR or FISH on a node like this. It would have been follicular lymphoma, that's it. Has the world changed so much in a few years? I always considered such testing to be ancillary, only used in difficult cases, and then the results have to be correlated with the morphology. What do you think of this?

 

[2121115]

Not personally my case, but my group recently made the diagnosis of follicular lymphoma, grade 3A. Due to the circumstances of the case, this diagnosis was based upon H&E and IHC alone. Flow could not be done. The morphology is classic, slam-dunk, 99 out of 100 hematopathologists would agree, take a picture and put it in a textbook classic (I'm not a hemepath, though we do have one here who agrees this is classic). Patient and material went to a nearby academic center for consultation where they decided to throw everything including the molecular kitchen sink at it. Well...FISH negative and B-cell gene rearrangement PCR reported as polyclonal. On the basis of these results, though they describe morphologically classic follicular lymphoma, they state that you can't call it lymphoma.

When I left training, all of 2.5 years ago, we never would have considered doing PCR or FISH on a node like this. It would have been follicular lymphoma, that's it. Has the world changed so much in a few years? I always considered such testing to be ancillary, only used in difficult cases, and then the results have to be correlated with the morphology. What do you think of this?

If this is all a true story, then that is an epic FAIL on the part of the academic center. Wow. No reason to order it in the first place, but even if it is negative you still call it FL. You don't treat patients based on black box molecular testing. There are so many reasons to get false negative results with the gene rearrangement in that situation.

 

[pathstudent]

Not personally my case, but my group recently made the diagnosis of follicular lymphoma, grade 3A. Due to the circumstances of the case, this diagnosis was based upon H&E and IHC alone. Flow could not be done. The morphology is classic, slam-dunk, 99 out of 100 hematopathologists would agree, take a picture and put it in a textbook classic (I'm not a hemepath, though we do have one here who agrees this is classic). Patient and material went to a nearby academic center for consultation where they decided to throw everything including the molecular kitchen sink at it. Well...FISH negative and B-cell gene rearrangement PCR reported as polyclonal. On the basis of these results, though they describe morphologically classic follicular lymphoma, they state that you can't call it lymphoma.

When I left training, all of 2.5 years ago, we never would have considered doing PCR or FISH on a node like this. It would have been follicular lymphoma, that's it. Has the world changed so much in a few years? I always considered such testing to be ancillary, only used in difficult cases, and then the results have to be correlated with the morphology. What do you think of this?

Send it to Elaine Jaffe at NIH.

 

[TMZ2007]

So are they going to treat it? Or "conservative" management only? Can you even treat a non-lymphoma? Strange. Conversely, does that mean all those other patients that you diagnosed and treated as lymphoma without ancillary testing should be re-evaluated?

 

[levels x3]

I realize you need to take my word for it regarding the morphology, but yes, this is an entirely true story. The morphology is absolutely diagnostic. We were similarly awestruck by the conclusion of the academic center, and perhaps even more awestruck that they did all of the molecular testing in the first place.

The case will be sent for a third opinion, though I'm not sure where yet.

Treatment was going to be offered if the diagnosis was lymphoma, but now the oncologist doesn't feel comfortable treating, because as you say, you can't treat non-lymphoma. To the point about subjecting all past lymphomas to ancillary testing now, two of our senior partners have somewhat jokingly (and somewhat seriously) threatened to retire if this isn't lymphoma.

 

[mlw03]

what's the clinical situation? does the patient have diffuse lymphadenopathy? i agree with the comments about why was it tested in the first place, but i can say having just come from residency that i'm not at all surprised. we had certain "protocols" for molecular testing in lymphoma cases, some because of oncologist preference, others for research protocols. more often than the described case i'd see something end up a double-hit lymphoma based on the finding of an additional translocation. but getting back to the clinical - if the patient has diffuse lymphadenopathy and the morphology you describe, how can they not treat? but if it's a solitary mass, that's different. what about bone marrow? isn't FL supposed to have high rates of marrow involvement? this case is a good example of not just sticking tissue in a box and expecting a perfect answer - something we actually do need to act like doctors.

 

[pathstudent]

I realize you need to take my word for it regarding the morphology, but yes, this is an entirely true story. The morphology is absolutely diagnostic. We were similarly awestruck by the conclusion of the academic center, and perhaps even more awestruck that they did all of the molecular testing in the first place.

The case will be sent for a third opinion, though I'm not sure where yet.

Treatment was going to be offered if the diagnosis was lymphoma, but now the oncologist doesn't feel comfortable treating, because as you say, you can't treat non-lymphoma. To the point about subjecting all past lymphomas to ancillary testing now, two of our senior partners have somewhat jokingly (and somewhat seriously) threatened to retire if this isn't lymphoma.

Was the BCL-2 immunostain positive on the follicles. What was the KI-67? The only thing high grade follicular lymphoma could be confused with would be a reactive node and those stains alone should suss it out. I remember that FISH for t(14;18)can be negative in high grade follicular, but it is a little odd that PCR would be negative for a clone.

 

[scienceguy19]

molecular fail

 

[2121115]

I have seen several cases where the H&E and IHC were lymphoma and the B-cell PCR was negative. It doesn't matter. The patient still had lymphoma. This is not all that uncommon and I am surprised that an academic center would make such a call. In fact, if you are waiting on a PCR test to make a diagnosis of malignancy, then you probably don't really know what it is and shouldn't sign it out.

 

[Torsed]

About the negative PCR in lymphomas, well thats a limitation of tests that may be run by your reference labs. Human/mechanical error factors there as well. I can hear the plantiff's attorney's saying: "Gee Dr. X, why didn't you order the PCR/molecular studies that the oncologists say would have affected their managment?.....looks at jury, and smirks, we don't want to assault Dr. X's intelligence, we are sure he/she is quite a cunning pathologist, but we just don't want him/her hurting future patients."

Yes, the sharks are in the water.

 

[levels x3]

Was the BCL-2 immunostain positive on the follicles. What was the KI-67? The only thing high grade follicular lymphoma could be confused with would be a reactive node and those stains alone should suss it out. I remember that FISH for t(14;18)can be negative in high grade follicular, but it is a little odd that PCR would be negative for a clone.

We didn't do our own BCL-2 because it didn't seem to be a question of reactive vs. neoplastic. It was reported as negative in the follicles by the academic center. We will repeat it once we get our blocks back. Ki-67 was not done, but we plan to do it along with the BCL-2. BCL-2 also is known to be negative in follicular lymphomas, and more likely to be negative in higher grade FL such as this. In my recent, brief reading about this, PCR can be falsly negative in upwards of 20% of cases.

Clinically, this is localized to the axilla, BM negative. Time will tell of course.

Despite the classic morphology and our confidence in the diagnosis, I will admit that better pathologists than me have been fooled before. I still think the odds of that are low in this case. If we are wrong though, it would call into question a lot of what was once called FL by H&E. Maybe we should start grinding tissue up and dropping into black boxes in lieu of morphology. If I can find some time, I'll try to post a few pictures.

 

[2121115]

We didn't do our own BCL-2 because it didn't seem to be a question of reactive vs. neoplastic. It was reported as negative in the follicles by the academic center. We will repeat it once we get our blocks back. Ki-67 was not done, but we plan to do it along with the BCL-2. BCL-2 also is known to be negative in follicular lymphomas, and more likely to be negative in higher grade FL such as this. In my recent, brief reading about this, PCR can be falsly negative in upwards of 20% of cases.

Stop. Hold the phone. I thought you said it was diagnosed based on H&E and IHC? Why didn't you do BCL-2? That is pretty standard even if you are "sure" it is lymphoma. While some FL's are BCL-2 negative, if you have a negative BCL-2 immunostain you need more proof that it is follicular lymphoma. If it is negative for BCL-2 IHC, negative for B-cell gene rearrangement, and negative for BCL-2 FISH, then that is starting to make me doubt the diagnosis also. I take back what I said about the academic center.

 

[Tissue issue]

Which immunostains did your group do before the case was seen at the academic center?

 

[yaah]

I don't know, man, reactive hyperplasias can be pretty florid. If it's truly a follicular lymphoma the PCR should be positive. I think a third opinion is warranted if you are highly suspicious this is malignant, but don't be shocked if it also gets called benign.

 

[pathomatic]

For B-cell PCR
I am assuming that FR1, FR2 and FR3 primers were used for IgH and primers were also used for IgKappa, Combined this has a sensitivity of more than 95%. There have been several examples of a clone using Kappa with a polyclonal IgH

 

[levels x3]

Stop. Hold the phone. I thought you said it was diagnosed based on H&E and IHC? Why didn't you do BCL-2? That is pretty standard even if you are "sure" it is lymphoma. While some FL's are BCL-2 negative, if you have a negative BCL-2 immunostain you need more proof that it is follicular lymphoma. If it is negative for BCL-2 IHC, negative for B-cell gene rearrangement, and negative for BCL-2 FISH, then that is starting to make me doubt the diagnosis also. I take back what I said about the academic center.

Ha! Indeed, it's entirely possible that we will be eating crow when this all shakes out, but still, I don't think so. Again, not my case personally and I'm not looking at it now, but it may have been only CD's 3,20,5,10 done. CD10 was abnormally overexpressed outside of the follicles though. I agree, BCL2 is useful (and I would have done it), but it's certainly not required for the diagnosis of FL.

Yaah, the case is going for 3rd and 4th opinions simultaneously (one our choice, and the other the oncologist's...his being based upon the recommendation of the original academic center)

I'm going to be working this weekend, so I'll try to post a few pictures. Perhaps nobody will agree with me then...Good discussion though and if we are wrong, it certainly calls into question the primacy of morphology in my mind.

 

[levels x3]

3rd opinion rendered, this one from a major academic center. They agree that it is follicular lymphoma. A post or two ago, I mentioned that CD10-positive cells were abnormally expressed outside of the follicles. They agree that the morphology and numerous CD10-positive interfollicular B-cells confirm the diagnosis.

Comments discuss how a certain percentage of FL will be BCL-2 negative and lack t(14,18), and that PCR for clonal IGH rearrangement can be falsely negative.

I know I never got around to posting a picture, sorry. I will still try to do so. My conclusion is what I started off with; molecular, IHC, and other ancillary studies can be extremely helpful, but the results need to be reconciled with the morphology. If not, why bother with an H&E.

 

[pathstudent]

3rd opinion rendered, this one from a major academic center. They agree that it is follicular lymphoma. A post or two ago, I mentioned that CD10-positive cells were abnormally expressed outside of the follicles. They agree that the morphology and numerous CD10-positive interfollicular B-cells confirm the diagnosis.

Comments discuss how a certain percentage of FL will be BCL-2 negative and lack t(14,18), and that PCR for clonal IGH rearrangement can be falsely negative.

I know I never got around to posting a picture, sorry. I will still try to do so. My conclusion is what I started off with; molecular, IHC, and other ancillary studies can be extremely helpful, but the results need to be reconciled with the morphology. If not, why bother with an H&E.

Thanks for the follow up. Make sure you fax their report to those clowns at the local university.

 

[yaah]

Comments discuss how a certain percentage of FL will be BCL-2 negative and lack t(14,18), and that PCR for clonal IGH rearrangement can be falsely negative.

lol, are these follicular lymphomas usually marrow negative and do they seem to regress without treatment?

 

[levels x3]

lol, are these follicular lymphomas usually marrow negative and do they seem to regress without treatment?

Heh, maybe. I don't have a better way to classify it though. Time will tell.