Strange lump has appeared near mares teat

[Dulciedoe]

I have a 10 year old Thoroughbred mare that I have just noticed a fatty lump near her teat that has appeared recently. She is not in foal so I am confused at what this could be. There is no discharge from the teat but one nipple is slightly larger than the other one. Can anyone throw some light on this?? Thanks in advance!

 

[Emz99]

Could be anything from a tumour to mastitis to an inflammatory reaction.
If it's appeared quite quickly
I'd get it looked at.

 

[Dulciedoe]

Thanks for your reply. The lump has now moved further down her stomach and has changed shape a little but has not grown. Time for the vet I think!