Liz Buchanan BVSc MRCVS
Hello! I would be a little concerned about any painless change / lump to the skin that has started small and then grown bigger, because that is how cancerous lumps tend to begin. This is a strange one - it seems to involve both a keratinized surface (pad) and a skin covered one (I keep wanting to move your dogs' foot and take a look round the corner) and has a change in pigment, which is particularly striking. Of course, it doesn't have to be cancer - there are other possibilities too, so it isn't time to worry - but it probably is time to show the lesion to your vet. If they are concerned, they may ask to take a biopsy (either now or in a few weeks, if they need to rule out histiocytoma first) so that their pathologist can identify it. Other possibilities may include a cyst, lipoma, an infectious, inflammatory or endocrine change or even a foreign body - please will you come back after your appointment and let us know how you get on? For more information, if you search in the blog for 'lump,' you will find some articles. I wrote one myself a few years ago that you might find useful and my colleagues have written plenty more since - please do let us know how you get on.