Immunohistochemical staining of neoplastic and inflammatory plasma cell lesions in feline tissues.

Two cases of feline plasmacytoma and nine cases of reactive plasma cell proliferations were examined for the presence of cytoplasmic immunoglobulin light chain types and heavy chain classes, by the peroxidase-anti-peroxidase technique on sections of formalin-fixed, paraffin-embedded tissues. This immunohistochemical technique is an important aid to conventional histological techniques. It helps to differentiate between neoplastic and dense inflammatory plasma cell proliferations by determining the presence of one, or more than one, light chain types in the cells, which corresponds with their neoplastic or reactive nature.