mammary carcinoma in male rabbit- advice please

Re: mammary carcinoma in male rabbit- advice please

sarah mason — Wed, 23 Feb 2011 10:45:34 GMT

Why not contact Edinburgh uni for advice as they have an exotics specialist and an oncology department so might have some experience of dealing with it or some prognostic info?

Re: mammary carcinoma in male rabbit- advice please

Kate Richardson — Wed, 26 Jan 2011 11:51:55 GMT

I didn't see the mass originally but from the records suggests the 'new' mass is at the same site.

I'm inclined to either go for 2 (b) or 3 (c). I just don't like to make a decision based solely on the animals age if it is otherwise healthy, but at same time at this age quality is far more important than quantity of life! But I will let the owner make the decison.

Thanks

Re: mammary carcinoma in male rabbit- advice please

Richard Fox — Wed, 26 Jan 2011 11:31:32 GMT

Hmm - no evidence of vessel invasion but obviously peripherally invasive. Given the presentation I would suspect the other lesions are carcinomas if in the mammary region. Aspiration is unlikely to confirm a carcinoma but maybe suggestive unless there is striking atypia. A biopsy would be required to confirm an invasive phenotype. Has the mass recurred i.e. at the same site or are these "new" locations? I was suggesting cytology to compare the cell morphology and thus if epithelial and the same cell type would suggest bad news if they have all arisen at the same time point? However primary skin tumours like basal cell tumours and trichoepitheliomas are all still possible but the location suggests mammary origin?

This is how I see it:

Ask owner what she wants to do:

1. Aspiration/biopsy is helpful but if the lesions are growing fast then this maybe academic.

2. Removal will probably give it a longer shelf life but explain long term prognosis is still pretty poor and a 9 year old rabbit has has a good innings.

3. Or one can leave them and will most probably call it a day sooner rather than later?

Re: mammary carcinoma in male rabbit- advice please

Kate Richardson — Wed, 26 Jan 2011 10:55:22 GMT

Just dug out the histo report-

'...within the mammary tissue....large densely cellular mulicavitated, partially encapsulated neoplastic mass. Multifocally, neoplastic cells extend through the capsule into the adjacent mammary tissue. Neoplastic cells are are arranged in wide trabeculae and nests and occasional tubular structures, supported by moderate amounts of collagenous connective tissue. Individual neoplastic cells are polygonal to cuboidal, contain small amounts of eosinophilic cytoplasm and have indistinct cell borders. Nuclei are moderately large, round to oval and contain lightly stipled chromatin. Mitoses are 1-2 per hpf. Neoplastic cells extend to within 1mm of the tissue margins. Adjacent mammary gland units are moderately to markedly hyperplastic.

Histological diagnosis: Ductular mammary carcinoma, umbilical region

Re: mammary carcinoma in male rabbit- advice please

Bob Russell — Wed, 26 Jan 2011 10:48:36 GMT

Mammary lumps are 'always' bad news and 'always' seem come back in rabbits even with fairly radical excision! Perhaps it is the deep margins that are the problem. I always warn owners that the prognosis is very guarded. New tumours in other glands seem to be very common as well!

Re: mammary carcinoma in male rabbit- advice please

Richard Fox — Wed, 26 Jan 2011 10:26:53 GMT

I personally would aspirate them and label them of course and they can be compared but I suspect the news is not good as mammary carcinomas in exotics are pretty bad news. Any indication in the histo report as to vessel of tissue invasion? Most carcinomas however tend to met to local lnns rather than other sites so these maybe more like de novo tumours?