B-cell (CD79a+) lymphoma affecting the tarsal joint synovia in a sheep

A lymphoma affecting the synovia was identified in both tarsal joints of an aged sheep. With a panel of cross-reactive antibodies specific for lambda and kappa immunoglobulin light chain, MHC class II, CD3, CD79a and the Ki-67 antigen, the neoplasm was classified as a B-cell lymphoma with uniform expression of surface membrane CD79a. This would seem to be the first report of a lymphoma affecting the synovia in a domestic animal, and the first use of the CD79a reagent on ovine tissue.