We describe a case of plasma cell gingivitis that occurred in the upper and lower gingivae of a 38-year-old man. As clinical findings in this patient, the peripheral region of the upper and lower gingivae was swollen and painful. The clinical diagnosis was gingival hypertrophy, and primary treatment for gingivitis and gingivectomy were performed. Histologically, many infiltrative plasma cells were observed mainly under the epithelium in the surgical specimen. Moreover, many cells stained positively with monoclonal antibody against anti-immunoglobulin kappa chain and anti-immunoglobulin lambda chain on immunohistological analysis. These finding suggested that the infiltrative plasma cells were polyclonal phenotype, and that the pathological diagnosis was plasma cell gingivitis and not plasmacytoma of the gingiva.
Based on our observations, we conclude that immunohistological analysis of the cytological phenotype of plasma cells is very important for the differential diagnosis of plasma cells gingivitis and plasmacytoma.
