Ted Bartlett- I know from experience with humans that simple renal cysts are fairly common and are a benign condition. What you're describing sounds like polycystic kidney. In humans, this may be a congenital condition that may be associated with other abnormalities sometimes; sometimes it's isolated. The problem is when there are so many cysts that the kidney can't function properly--then a nephrectomy (removal of a kidney) may be necessary if the patient has persistent blood in the urine, pain, or worsening renal function. Dr. Williams, can this be generalized to ferrets? Greg Mohs- I had a picture of me and my three fuzzies made into a Christmas card--will gladly send you one if you want, but I need your address again. Will let everyone out there know how my crew responds to my tree after I put it up after TG. Hugs to all carpetsharks! Chad Jackson (Zack, Zackie, Zack Zack Kerouac, JP) Binky (Ms. Bink, Binkarina, White Princess, NO!!) Possum (Little one, Weenie) [Posted in FML issue 1386]