Percutaneous Biopsy: How to Help Pathologists Maximize Diagnostic Certainty

[Dr. Chris Beck]
How certain do you have to be to then put out a pathology report that says this is the answer? Because sometimes it says non-diagnostic, maybe we need-- it'll make a different recommendation and maybe that varies from practitioner to practitioner. Even in straightforward cases, it's probably hard to be 100% certain but when I think about radiology, in diagnostic radiology, there's always that out that some radiologists will say like, "Oh, correlate clinically."

Or maybe if we had a super secret MRI or something, but you guys don't really have much of an out other than saying, "Hey, we need more tissue." But you have to have some degree of certainty to then say like, "This is the diagnosis. Treatment recommendations are based on like what you guys say, so how certain--

[Dr. Andrew Sholl]
That harkens back to how good is the biopsy. When I hedge and when I hedge, that typically falls into one or two categories. You basically have benign, atypical, suspicious, and malignant. That's the big four that we're falling into. When I fall into the atypical and suspicious categories, it's usually because I don't have enough tissue. That's usually what it comes down to.

I'll have a lung cancer, there's tiny stuff on the edge. I can't do any immunostains on it because it will disappear. If I do do immunostains, then the cells are not there anymore. My hedge is that I know this is non-small cell cancer, but I can't call it squam, I can't call it adeno, I can't call it a met. It falls into the, I know it's cancer, but I can't tell you anything more than that. That makes it sometimes difficult for the hematologist, oncologist to treat.

[Dr. Chris Beck]
Sometimes I feel like samples can get sent out and not necessarily for next-gen sequencing, but you can send them out for a second opinion. Is everyone's threshold different for that?

[Dr. Andrew Sholl]
Everyone's threshold is different, but I can speak to my threshold. My threshold is this looks like tumor X, but the immunostains stain like tumor Y and I don't have a name for it. There's plenty of tissue there, but the name that I want to put on it doesn't have enough supporting evidence, whether it's immunostains or flow or whatever to put that name-- rubber stamp that name on it.

That's when I will step back and say, okay, the tumor looks like an adeno, but it stains like a squamous. It looks like this, but it stains like a kidney, but the guy's got a history of colon. When the clinical picture doesn't fit with what's on the slide, that's another reason for me to step back and say, I'm not sure what I'm doing here. Let me send this out somewhere where they can do more advanced testing whether that's next-gen sequencing or more immunostains that I don't have access to.

[Dr. Chris Beck]
Is that sometimes the case? It's not necessarily-- I'm framing it like this, like a caricature, but it's not like, "Oh, Dr. Sholl's brain is too small, so he has to have someone else think about it." People have access to different tools that you just-- if were to-- okay, that you just don't have access to.

[Dr. Andrew Sholl]
No, that's absolutely correct. As an example, they will do brain tumor biopsies, excisions at our institution. The way that these brain tumors are now categorized is whether they're IDH1 mutant or not. Then, so the glial neoplasms, they need these tests in order to categorize them that I just don't have access to. I know it's a glial neoplasm. I know it's a high-grade glial neoplasm, but in terms of categorizing it, I don't have the tools at hand to do that.

It's cheaper for me to send it out to a higher-end neuropathology institution that has an IDH1 immunostain or-- yes.

[Dr. Chris Beck]
Just sitting there on the counter, I guess. I don't know.

[Dr. Andrew Sholl]
Yes.

[Dr. Chris Beck]
One of the things that interventional radiologists will say, or one of the things I was taught is you biopsy your infections and you culture your tumors. Meaning that almost in all scenarios, whether you think it's a tumor or infection, you're going to get a culture. The same thing with if you think it's an infection, you biopsy it. Do you see the cultures? Do you find that helpful? Are there ever situations where like, interventional radiology thinks like it's a primary lung tumor and then you get all these cores back and you're like, "Man, they didn't send any of this for culture?"

[Dr. Andrew Sholl]
Oh yes. It drives me crazy.

[Dr. Chris Beck]
[laughs] Okay.

[Dr. Andrew Sholl]
For example, last week we had an orbital tumor that was biopsied and he thought it was a tumor. He thought it could be, whatever. Then I put it on the microscope and it's granulomatous inflammation. I better go check the EMR and see if there's cultures in there. You look and you're like, well, there could be an acid-fast bacillus in there but the sensitivity of a tissue and a stain is so much smaller than a culture.

Yes, that saying is absolutely-- I will go to the EMR and look and see if a culture has been done all the time. The other thing too is that it's particularly in lung, you get those obstructive lesions and you'll get a pneumonia behind it. The needle might be in the pneumonia, but you're going to treat the tumor and you're also going to treat the pneumonia. In that instance, it's important to get both. Yes, absolutely.

[Dr. Chris Beck]
Okay, because sometimes you see on the pathology report where you guys do actually make a lot of comments about an infectious etiology, like if cultures aren't said, it's always-- I read those, I'm like, oh, well, it looks like they got it. They figured it out. It's not infectious. What you're saying is you're doing the best with what you have, but having a culture would've been very nice.

[Dr. Andrew Sholl]
Yes. I mean, could put a gram stain on a core, but it's going to tell you gram-positive cocci. Then your ID doc is going to call you and be like, "Anything else?" Because they need to know sensitivities and all that stuff on the bug that's there. All I can tell them is that it's a gram-positive cocci.