查了下: (1)脾肿大可能与其它病相关,不一定是脾本身的问题. (2) 脾生癌的话, 有可能不扩散

(3) 脾可以被完全切除而猫仍然正常生活. 

In most instances, the causes of an enlarged spleen in cats are due to a secondary condition and not from the spleen itself. These triggers can commonly include immune disorders, bacterial infections, tumors of the spleen, inflammatory bowel disease, and injuries to the abdomen.

参考链接:  https://www.aspcapetinsurance.com/resources/feline-spleen/#:~:text=In%20most%20instances%2C%20the%20causes,and%20injuries%20to%20the%20abdomen.?