Lymph Node Biopsies in a subcutaneous MCT case

RE: Lymph Node Biopsies in a subcutaneous MCT case

Anthony Dennison — Mon, 11 Jun 2018 09:10:50 GMT

[quote user="David Mills"]n reply to the OP, my limited anecdotal experience is that I've never seen a metastatic MCT in 10 years of practice. I'm sure others have. But I do think that one can go overboard with MCT investigation when we don't really know how dangerous they really are in the vast majority of cases.[/quote]

It's interesting to hear that. In the last 12-18 months I've dealth with 3 cases of high-grade MCTs with cytological evidence of mast cells in the liver and spleen. One with gross visible splenic masses on ultrasound. The 2 with only cytological evidence were given vinblastine and preds and did fine. The one with visible splenic masses declined staging initially, but re-presented 6 weeks later with a massive draining lymph node and the abdominal changes - responded excellently to Masivet. Within 6 weeks of treatment there was no cytological evidence of mast cells on liver and splenic FNAs and the gross lesions had disappeared entirely.

My population is slightly skewed as we have 17 branches and I'll only deal with the high grade ones after the histo has come back - there'll be loads more low grade MCTs removed that no one asks me for advice on. In fact, the dog in this case also has a low grade MCT on her rump that I haven't even thought about.

RE: Lymph Node Biopsies in a subcutaneous MCT case

David Mills — Fri, 08 Jun 2018 22:46:43 GMT

[quote user="Liz Barton"]

[quote user="Edward Jones"]My understanding was that the steroids let you see the actual size of the MCT, not including the recruitment of non-neoplastic mast cells that might make the tumour look bigger and lead to unnecessarily large margins.[/quote]

I have used pre-op steroids a couple of times with good success - a tennis ball sized mass on a labrador distal limb that reduced to a golf ball - removed (with pie-lattice releasing incisions around the limb to enable closure). All healed well and no recurrence. This same dog also had diffuse ulcerating lesions along it's flank which when FNA'd anywhere showed MCT. I had no idea what I was going to do surgically, but these lesions completely resolved with the pred pre-op!

[/quote]

The pre op preds interest me quite a bit as I've similarly had masses almost completely disappear in the 2-3 weeks. It makes one wonder how much of a rapidly growing mass is just inflammation. Normally distal limb like you, but higher numbers, est >100 from mine and colleagues' cases. We used to do histo on these and I think around 80pc were low grade. Makes me wonder whether e.g. trauma kicks off an inflammatory response or somesuch.

As a result large or difficult looking MCTs always get a course of preds first.

In reply to the OP, my limited anecdotal experience is that I've never seen a metastatic MCT in 10 years of practice. I'm sure others have. But I do think that one can go overboard with MCT investigation when we don't really know how dangerous they really are in the vast majority of cases.

But then, on the flip side, my oncology knowledge/practice being in charity is cut it out or nothing (or pts).

Added to that, Gerry always gives refreshingly pragmatic and direct advice on here so best listen to him rather than my cognitively biased musings!

RE: Lymph Node Biopsies in a subcutaneous MCT case

Liz Barton — Fri, 08 Jun 2018 11:18:03 GMT

RE: Lymph Node Biopsies in a subcutaneous MCT case

Gerry Polton — Fri, 08 Jun 2018 10:54:20 GMT

Thanks for finding that, Edward.

RE: Lymph Node Biopsies in a subcutaneous MCT case

Edward Jones — Fri, 08 Jun 2018 09:31:32 GMT

[quote user="Gerry Polton"]Concerning the pre-op use of steroids, I don't know how to search prior posts but somewhere on this forum I have written about my spider-splat analogy. [/quote]

https://www.vetsurgeon.org/uk/small_animal/f/167/p/19854/119208.aspx

My understanding was that the steroids let you see the actual size of the MCT, not including the recruitment of non-neoplastic mast cells that might make the tumour look bigger and lead to unnecessarily large margins. But I will obviously give way to Gerry on the topic!

RE: Lymph Node Biopsies in a subcutaneous MCT case

Gerry Polton — Fri, 08 Jun 2018 09:09:47 GMT

Send me a photo if you can. We can achieve curative margins with interdigital tumours most of the time. I would strenuously advise against the 'cut out as much as you can' approach.

Concerning the pre-op use of steroids, I don't know how to search prior posts but somewhere on this forum I have written about my spider-splat analogy. It's worth taking a look if any of you know how to search (I'm sure it's actually really easy, sorry I'm such a Luddite)

Gerry

RE: Lymph Node Biopsies in a subcutaneous MCT case

Edward Jones — Fri, 08 Jun 2018 09:04:45 GMT

Consider using steroids pre-op to reduce the recruitment of non-neoplastic mast cells, which may reduce the required margins.

RE: Lymph Node Biopsies in a subcutaneous MCT case

Anthony Dennison — Fri, 08 Jun 2018 08:54:05 GMT

[quote user="Gerry Polton"]

Hi Anthony

We talked about this a lot at a recent conference. The consensus is that HN1 = don't worry about it. So long as you have fixed the primary tumour, you have probably cured the patient.

HN2 and HN3 are metastatic.

Cheers

Gerry

[/quote]

Thanks Gerry - the primary tumour hasn't actually been removed yet (case that one of our vets referred to me for work up - all she had done is biopsy the mass not remove it before sending it to me for staging. I know, I didn't understand either).

It's a tricky one to remove as it's interdigital and not a distinct mass, just an area of swelling so will be difficult to take margins. Would you recommend something like Masivet to shrink it or just cut out as much as possible?

RE: Lymph Node Biopsies in a subcutaneous MCT case

Gerry Polton — Wed, 06 Jun 2018 12:50:59 GMT

Hi Anthony

We talked about this a lot at a recent conference. The consensus is that HN1 = don't worry about it. So long as you have fixed the primary tumour, you have probably cured the patient.

HN2 and HN3 are metastatic.

Cheers

Gerry

RE: Lymph Node Biopsies in a subcutaneous MCT case

Matt Hilary — Wed, 06 Jun 2018 12:07:13 GMT

Weishaar et al (2014):

[quote]

HN0: None to rare (0-3), scattered, individualized (isolated) mast cells in sinuses (subcapsular, paracortical or medullary) and/or parenchyma per x400 field (0-3 mast cells per x400 field), or does not meet criteria for any other classification below. Non-metastatic.

HN1: Greater than three individualized (isolated) mast cells in sinuses (subcapsular, paracortical or medullary) and/or parenchyma in a minimum of four x400 fields (unless otherwise stated, at least four x400 fields each, which contain more than three mast cells). Pre-metastatic.

HN2: Aggregates (clusters) of mast cells (>3 associated cells) in sinuses (subcapsular, paracortical or medullary) and/or parenchymal, or sinusoidal sheets of mast cells. Early metastasis.

HN3: Disruption or effacement of normal nodal architecture by discrete foci, nodules, sheets, or overt masses composed of mast cells. Overt metastasis.

[/quote]