Greetings all. My question as a newbie is ask about a possible relationship between our cat having had a tumorous spleen and splenectomy and now a diagnosis of diabetes. Our large 18 lb Maine Coon X, male, 13 yrs old, experienced a sudden and severe weight loss (down to 9 lbs.) this fall. He was diagnosed on Oct 3 with a cavitated irregular mass in his spleen and had surgery shortly after. His post-op went very well. He gained some weight with SD a/d. However, by mid November he was losing weight again and drinking water and peeing excessively. He was diagnosed with diabetes, first starting with 1 unit of Lantus daily, now increased to 2 units daily. I haven't done any testing myself yet. His levels went from the 500's to 220 and then his thirst and peeing increased again and that's when the vet increased his Lantus to 2 units daily. Tony goes back this Thursday for testing. They want him all day, no food, no insulin before I bring him in early in the morning. He's been on SD w/d and did very well until we ran out. I bought him some FF classics yesterday to tie him over until Monday when I can get some more w/d from the vet. Now Tony has diarrhea :sad: . I know treating diabetes can feel like being on a roller-coaster, but I wonder how much of this (the diabetes) is attributable to his original dx of spleen tumor and surgery. Even though the pre- and post- op testing and blood work all show signs of an otherwise healthy cat, I can't help but worry that there is some kind of relationship. It's really upsetting to me and to my Tony.