I noticed a raised lump on my Staffordshire bull terrier aged 8 on the 21st of November on my dog head that ulcerated the next day. The ulcerated lump scabed over then got knocked off the following week. I have been to 2 different vets within that time and both feel it either a histiocytoma or a mast cell tumour with both vets leaning toward it being a histiocytoma but only a biopsy will make sure. I have a biopsy for Wednesday but my question is would it be worth doing is this lump too close to the eyes for good margins? I have done days of googling and I see 1cm is all that needed for good margins and 90% of other sites saying 2-3cm is needed. I would not put my dog through radio therapy so if good margins is not possible would it be worth doing a biopsy? Another thing is I know it low chance but I don’t want to risk Anesthesia with my dog being that 1 in 2000 dog to die from it. Anyone know if good margins is possible from looking at the picture of my dog?