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]