Yes, aspiration is the only way to tell if a ferret truly has lymphoma.
This will also tell you what stage the lymphoma is at. At that point
you can decide whether to treat with chemotherapy (a good protocol
that involves SQ fluids instead of IV fluids is Tufts Protocol, a less
stressful and updated ferret chemo - others are usually derived from
cat and dog protocols). Or you can just do palliative treatment. A
biopsy/explore will also usually confirm lymphoma; sometimes lymphoma
can be seen in a radiograph on the lungs. It all depends on other
symptoms but yes, the definitive diagnosis is made by observing the
biospied cells.

Good luck,
Laryssa

[Posted in FML 5861]