Stomatitis in cats, sometimes called gingivostomatitis, plasma cell stomatitis, or lymphoplasmacytic stomatitis, is a very painful condition... (texaswestveterinarian.com)
MGUS can also become cancer, such as multiple myeloma, lymphoplasmacytic lymphoma, or chronic lymphocytic leukemia. (vicc.org)
An example of kidney damage that is common to cats is lymphoplasmacytic nephritis and chronic interstitial nephritis. (mypetneedsthat.com)