To Laura MacDonald concerning lymphosarcoma: First off, I want to say that Katie gave an excellent review on lymphosarcoma. There are a few IMPORTANT things that I want you and everyone else to know before considering chemotherapy in a case like this. LYMPHOSARCOMA CANNOT BE DIAGNOSED ON THE BASIS OF A HIGH LYMPHOCYTE COUNT!!!! This is a fallacy that has become entrenched in the ferret literature in the last few years and has resulted in large numbers of animals receiving needless chemotherapy. This is probably why we have so many animals in "remission". By far, the most common cause of elevated lymphocyte counts in animals is a chronic smoldering infection, not a tumor. Ferrets over the age of three often have such infections (primarily in the stomach due to Helicobacter infection) which can raise the number of lymphocytes in the blood to "over 35." There have been no studies on the numbers of ferrets with a high lymphocyte count having lymphosarcoma, only some anecdotes by a few private practitioners to that effect. A lymph node biopsy, read by a pathologist who is familiar with ferret tissue is the ONLY way to diagnose lymphosarcoma. To treat based on a high preipheral lymphocyte count only is a mistake, and I would NEVER do such with my own animals. And, as you say, your ferret acts fine!!!! (If you decide to pursue this further, I would be happy to look at your ferret's biopsy.) Bruce Williams, DVM Department of Veterinary Pathology [log in to unmask] Armed Forces Institute of Pathology (202) 576-2453/2454 Washington, D.C. 20306-6000 [Posted in FML issue 0937]