Feline mast cell tumours

Re: Feline mast cell tumours

Nicola Cole — Thu, 03 Jul 2014 22:18:22 GMT

More info: first presented 18months ago 'a bit quiet'...whether related or not is unsure but next appt (14 months) suggests this was ongoing and at some point between the 2 appointments she started vomiting a few times a week. Ex lap a month later as although bloods not overly exciting trial meds didn't improve anything. Found diffuse thickening from stomach to ileo-caecal junction, multiple biopsies and from ex lap gross appearance was presumed was going to come back as lymphoma. Initial histo report: suspicious for gastric round cell tumour, positive staining for mast cells. Immunohistochemistry offered to confirm MCT and exclude lymphoma but wasn't done. Was apparently presumed mast cell tumour from this and started on preds and tagamet (masivet discussed but very difficult cat re regular blood sampling). Did really well for over a year, then as was doing so well the owners wanted to check the diagnosis (as presumably had been told MCT would've generally progress quicker than this). The lab has now been asked do immunohistochem for lymphoma.....

Re: Feline mast cell tumours

Nicola Cole — Fri, 27 Jun 2014 21:14:02 GMT

[quote user="Gerry Polton"]

Hi Nicola (Hi Martin)

As a footnote, I would add that there was a time when nine out of every ten feline intestinal mast cell tumours I was referred were actually alimentary lymphoma cases. It doesn't seem to happen nearly so much now. But that might be another possibility. This could be a lymphoma that was perhaps steroid-responsive. To be honest, the story would still be a good one even if that were true though.

Gerry

[/quote] My first thought on this was 'is it a lymphoma rather than mast cell tumour-contact the lab to get original report' as the full histo report wasn't on the history, to see if was a definitive diagnosis. Being a part-time locum I'm not back there til next week so can post more details then (biopsy type, whether lesion removed or just biopsied, full histo report)....thanks for replies (and sorry for lack of paragraphs!)

Re: Feline mast cell tumours

Gerry Polton — Fri, 27 Jun 2014 16:56:05 GMT

I'm quite sure there were no dodgy pathologists. It is simply a question of knowledge-sharing. Some feline alimentary lymphomas comprise a collection of bad T cells which produce cytokines that attract mast cells and eosinophils into the site of the tumour. They do this so well that the neoplastic cells might account for only 10% or so of the overall volume of the intestinal mass with the overwhleming majority of other cells being normal looking mast cells. The key is realising that the mast cells are indeed normal looking, rather than overtly atypical. Since it is not normal to see mast cells accumulating in cats' intestines, the sheer number of cells would lead to a diagnosis of mast cell tumour. We know better nowadays.

Re: Feline mast cell tumours

Martin Atkinson — Fri, 27 Jun 2014 16:47:17 GMT

[quote user="Gerry Polton"]As a footnote, I would add that there was a time when nine out of every ten feline intestinal mast cell tumours I was referred were actually alimentary lymphoma cases. It doesn't seem to happen nearly so much now.[/quote] I had feeling of deja vu as I read that and seem to remember I found a similar trend. Maybe there was a dodgy pathologist at a lab we used or some lymphoma cases look histologically similar to mast cells.

Re: Feline mast cell tumours

Gerry Polton — Fri, 27 Jun 2014 15:56:58 GMT

Hi Nicola (Hi Martin)

This is a fascinating case. Answering from my experience alone, I know of two cases which have been treated for intestinal mast cell tumours by excision which remained disease free for over a year. Both then relapsed in the second year, I would guess about eighteen months after excision. I have never heard of a patient surviving a year with a gross mass still in situ, or a gross mass that was then treated with corticosteroids. However, I would say that the history provided certainly fits with what I would consider possible. The chronic anaemia makes sense.

Thanks for the information. I'm always learning.

Gerry

Re: Feline mast cell tumours

Nicola Cole — Fri, 27 Jun 2014 12:41:46 GMT

Thanks for quick reply. This cat has become very anaemic-HCT of 10! I've have advised bloods and smear to external lab to make sure is as anaemic as in house says. Unfortunately the cat is completely un-handleable, has to be blood sampled after crush cage sedation, so no way to examine muc mems etc unsedated. But from the info I was told it's very unlikely this cat is suddenly this anaemic as happily running around...so am presuming much more chronic anaemia, whether due to low level intermittent GI bleed or not.....

Re: Feline mast cell tumours

Martin Atkinson — Fri, 27 Jun 2014 09:17:43 GMT

I had a cat which lived for more than a year from first symptoms with only symptomatic treatment before it suffered a catastrophic splenic bleed secondary to mast cell invasion, histology at PM reported the spleen and intestine were largely composed of just mast cells!!

For further information wait for Gerry he will almost certainly be along soon.