Potential mammary gland tumor

I took my kitty (7ish, female) to the vet because she had a lump on her stomach and a swollen nipple and they think it’s a mammary tumor. They tried to do an FNA but she flipped out on the vet staff so they sent her home with gabapentin to come back on Wednesday. They also talked about doing scans to see if it’s spread, but I’m not sure if I should wait until the fna results come back to see if it’s even a) a tumor and b) malignant. I suspect it is both because of the shape, size and feel of the mass, but I’m obviously not 100%. Any advice/insight/anecdotes would be appreciated! She had an anal gland issue a few years ago and an ear infection last year, but that’s it for health issues. No changes in behavior thus far