FNA on solid hind leg tumor
My dog (14F, small mixed terrier) recently had an in-office FNA performed after I found a new lump (located on rear left leg) that didn't feel like the other lipomas she has. My vet doesn't think it's benign, but she also doesn't think it's a soft tissue sarcoma.
I work in a lab and had my pathologists review these photos. The hematopath was trying to determine whether a matrix was present in the clumping, and cytopath said they looked epithelioid or hisotocytic, but she was honest about the disparities between human and animal pathology.
I opted for an excisional biopsy to be performed next week for definitive diagnosis and can update when that report comes back. In the meantime, I'm just curious about the morphology, what kind of distinctive cellular features might differentiate those two options and what one would look for between a benign or malignant tumor (for instance, I don't see any mitotic cells here). I'm competent in peripheral smear morphology in humans, but even body fluids, we only report main WBC lineage. Anything abnormal is just "other" and referred to pathology. Anatomic pathology is not my wheelhouse at all.
Not looking for a diagnosis, just hoping to have some better understand of what I'm looking at if that's okay!