Spleens can enlarge and not be a bother the main point of question is: "Is
the ferret ill?" Is the ferret lethargic?  Lymphosarcoma may also cause the
spleen to enlarge in a short amount of time.  We at the shelter have seen
this over and over again.  Six years old for a early alter ferret is a good
lump of time, but if the enlargement of the spleen has occurred in a short
amount of time and there are other symptoms which suggest infection then
take it out.
 
I also encourage anyone who does a spleen removal surgery on their ferret to
also have the pathology run so -- if necessary -- you can monitor the
condition and treat with steroids if and when warranted.
[Posted in FML issue 1719]