How common are misdiagnoses in cancer pathology?
February 22, 2018 1:46 PM   Subscribe

I was recently diagnosed with non-Hodgkin's lymphoma on the basis of pathology results from a lymph node biopsy. There seem to be some doubtful or anomalous things about the findings. Is it reasonable or feasible to try to get the samples retested to exclude all doubt, and if so how do I go about it? YANMD etc.

Short version: a lymph node under my jaw swelled up a few months ago. It was biopsied a couple of times, then excised. Pathology results seem to show diffuse large B-cell lymphoma, and doctor recommended chemo, but I want to make absolutely sure of the diagnosis before starting treatment.

Longer version. First biopsy, a couple of months after I first noticed the lump, was a fine needle aspiration biopsy, which showed nothing -- it came back normal/negative and the doctors said I could rest easy. However, the swelling did not subside and they then did a core biopsy; the pathology results came back with a diagnosis of "lymphoma, suspicious for diffuse large B-cell lymphoma", with a recommendation to excise the node and test it further. I have the pathology report and from what I can understand, there were clearly some unusual findings -- it actually uses the word "unusual" twice, as well as phrasings like "interpretation of this finding is somewhat problematic" and other things which suggest doubt in the diagnosis (but I can't make out if the doubt is whether it's lymphoma at all, or about the specific type).

I had surgery three weeks ago and the mass was sent for further tests. The results haven't come back yet. I met with an oncologist, who told me that the lab was running one more specific test to rule out a rare type of lymphoma, but that otherwise the results seem to confirm the DLBCL diagnosis. I think the pathologist is the same one who worked on the core biopsy. The doc didn't know when the results would be in, but has already sent me for a bone marrow biopsy and PET CT scan and wants to start chemo very soon.

I've also had several sets of blood tests, which all came back normal. My age (39) is I gather also atypical for lymphoma, and I'm in perfect health as far as I can tell, no symptoms at all. I realize the path results are more likely correct than not, but I want to be certain.

I asked the oncologist about getting the tissue retested and he kind of pooh-poohed the idea saying the likelihood of error was low, I'd have to get it done privately and he wasn't even sure if they kept the tissue and it was feasible. (I should probably have pressed him more on this question, but I had a lot of questions and was feeling rather overwhelmed.)

Obviously the final results should be more informative when they come in, but I don't know when that will be and the onc seems to be in a hurry to start chemo. What can I do right now to help rule out a misdiagnosis? What are the chances of such an error? Can I get the tissue retested at another lab and if so, how do I go about it? If I can't get it retested, does it make sense to have another hematologist/oncologist look at the same path results or will they just say the same thing? What else should I be thinking about in terms of feeling sure about the diagnosis before starting any treatment?
posted by zeri to Health & Fitness (9 answers total)
 
Has your oncologist given you any reasonable explanation of the wording of the results from the pathology report? As a non-doctor (I presume you are, too), I agree that the description of the results would give me pause. On the other hand, IANAD, so if I had a doctor I trusted, I would want my doctor to say one of a few things. Either "Oh yeah. What that's pointing to is that we're not sure of the exact type of lymphoma, but it's definitely lymphoma," or "There is some uncertainty about whether it's lymphoma, but from looking at test XX and test YY, I think there's a very good chance that it is and we want to catch it early," or "I'm not sure exactly what that's referring to; let me talk with the lab that did the analysis and get back to you."

Basically, the thing I want in any doctor is for them to take my questions seriously. I don't know whether a re-test in your case makes any sense, but as a patient, I also don't want to have to know whether a re-test makes sense; I want to have a doctor that I trust that can tell me that.

"Get a second opinion" is a saying for a reason. If you feel like your oncologist is brushing you off, see what another one says.
posted by Betelgeuse at 2:19 PM on February 22, 2018 [2 favorites]


Why do you think it's a misdiagnosis? Just that report?

Those pathology or radiology reports aren't really written for lay readers. We read them anyway, of course, but there's a particular style they use even beyond the technical jargon which can be opaque or misleading. People take different approaches to how much they want to know about their serious health issues, and that should be respected, but one approach that is guaranteed to drive you insane is the one-third-researcher: latching onto one thing that you admittedly don't really understand and aren't prepared to put into context, because you haven't done all the research you need to in order to make sense of it. If you're going to go to the level of scouring the path report, you have to educate yourself in the technical detail. Brief Googling shows me that fine-needle aspiration is of limited diagnostic value when it comes to lymphoma and that core biopsies are considerably better, but the excisional biopsy you just underwent is considered "the gold standard" for diagnosis. I'm not saying you're dumb or anything for not doing that; I'm saying, though, that if you don't want to do it, then reading the path reports is only going to confuse and upset you, not benefit you.

Your doctor should be willing to explain any anomalous results in the core biopsy report to you if you ask. Do ask. (If he's not, that's a good sign he may not be the best.) But I'm going to be blunt: you want certainty, absolute certainty. You can't have it. In the land of cancer, there is no certainty. The doctor wants to start chemo pronto because that is recommended for DLBCL, as the prognosis is much better if it hasn't spread. (Again, brief Google.) If you have other doubts or uncertainties, you should definitely go over the plan with him and discuss any concerns you have about, for example, side effects. It's your body and you get to decide. But if you set a standard of certainty, you're going to kill yourself refusing treatment.

(Saying this all as someone who had a hard-to-diagnose premalignancy who disagreed with her doctors' assessment, which affected treatment in a big way, and turned out to be right, but also saw a lot of people struggling with how to deal with information.)
posted by praemunire at 2:30 PM on February 22, 2018 [1 favorite]


I worked with a pathologist as part of a treatment team, though I'm not a physician or even a doctor. We, a teaching hospital, reviewed outside slides on behalf of patients who approached the physician I worked with every week. Out of 10 or 15 cases, 25% might be sent from referring hospitals. If your oncologist is not part of a teaching hospital, I would suggest asking him to send your slides - from all biopsies - to a reputable teaching hospital, preferably one with a stellar oncology program. That's where the best oncology pathologists choose to work, and if there is any really unusual aspect to your biopsy, that's the best setting for expert interpretation.

I am not sure how you would go about contacting an oncology hospital pathologist "cold", but your request to have your case reviewed by a pathology expert in the field should be gracefully accepted, and he should facilitate this. I cannot imagine that your oncologist wants to proceed with a treatment plan if there is doubt. I never heard of such a thing as "I don't know if we have the tissue". He seems to know nothing about pathology. Does he go to the pathology sessions to review the slides with the pathologist or is he just reviewing the report? The best clinicians review cases with the pathologist if there are unusual aspects.

When tissue is submitted to pathology, the staff embeds samples in paraffin blocks. Paper thin (thinner than paper, actually) slices are shaved off to be affixed to a slide. These slides are stained with numerous stains that react with specific parts of the cells, like the connective tissue, or viral particles, and the pathologist orders specific stains depending on the suspected diagnosis. The pathologist reviews slides and issues a report. When another opinion is needed, the slides and report ares sent to the new pathologist, not raw tissue. If the new pathologist wants new stains, he or she will request new unstained slides shaved from the paraffin block, which is kept by the original hospital in perpetuity.
posted by citygirl at 3:26 PM on February 22, 2018 [4 favorites]


I’m not a doctor, but a friend is a pathologist at a major cancer center, and whenever a patient comes in from another institution, they review the original slides to confirm the diagnosis. They never just accept the original pathology report. So I don’t know how common errors are, but having another pathologist look at slides is super common.

Also, I am so not a doctor, but my understanding is that chemo is almost never an emergency. You don’t want to wait six months, but you don’t have to start treatment tomorrow. From what you say, I’m wondering if you can try to see a different oncologist. I have cancer, though a different kind, and it’s very important to feel like your oncologist takes you seriously.
posted by FencingGal at 3:49 PM on February 22, 2018 [1 favorite]


When i had a prostate biopsy, the local pathologist said "not cancer" but sent the samples to an acknowledged expert who said "cancer". Pathology is sometimes a judgment call and second opinions are commmon.
posted by SemiSalt at 5:27 PM on February 22, 2018


If you do want to go for a second opinion, make sure in advance your insurance will cover it. They can be weird about them. I would not be surprised if they were stubborn about paying for a re-review of a preliminary biopsy's results when an excisional biopsy is available. You definitely don't want to get stuck with unexpected charges on top of all the other stress.
posted by praemunire at 9:47 PM on February 22, 2018


IANAD either but just went through a whole lymph node thing. I also had normal bloodwork, but was told that's not necessarily indicative of much re: lymphoma, and that the results of an excisional biopsy would be the major determining factor. They actually skipped a FNA biopsy and went straight to an excision for me, because evidently it can be difficult to find suspect cells given the small sample size, and false negatives aren't uncommon with FNA.

Since both the core and the excisional biopsy came up suspect, and since the phrasing you quote there sounds like it's saying 'this is lymphoma, we think it's probably diffuse large B-cell lymphoma but there are some unusual things that could mean it's a different kind of lymphoma,' it does sound like they think they're on the right track. Both the bone marrow biopsy and the PET/CT will help give them a better idea of the situation. PET/CT in particular helps show them where exactly lymphoma is metabolically active -- basically, where it is and how aggressive it is -- so that may help you feel the diagnosis is confirmed.

But if you feel like people aren't explaining things sufficiently, you definitely should contact the oncologist, or your GP/the person who referred you to the oncologist, and ask if you can have some clarification. My people were really good about explaining everything -- I second the teaching hospital suggestion above, because my experience at one was super great. I hope your doctors explain to you as well! Good luck!
posted by halation at 4:57 AM on February 23, 2018 [1 favorite]


I work at an oncology center. I do the authorizations for imaging and treatment, as well as schedule biopsies for patients. It's not super uncommon to ask for a second opinion. You can ask for your slides (samples) to be sent to another hospital or have a second look made. It may take a while though, which could slow down your treatment. It's not impossible if you have the support of your physician. He seems confident in your diagnosis likely because he works closely with the pathologist and trusts his opinion.

TLDR; Don't be afraid to ask for another opinion in regards to pathology!
posted by Sara_NOT_Sarah at 7:11 AM on February 23, 2018


Retired oncology nurse here.
NHL has dozens of sub-types and interpretation an be pretty subjective. It is absolutely worthwhile to get a second opinion. The path department saves slides for years, literally. So for your oncologist to say that he's not sure if they will even have them is a little weird.
posted by SLC Mom at 9:09 AM on February 23, 2018 [2 favorites]


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