Primary extranodal lymphoma of the oral cavity: an immunohistochemical study

Eleven cases of primary extranodal lymphoma occurring within the oral cavity were studied using an immunoperoxidase technique on formalin fixed paraffin embedded tissue to detect immunoglobulin, J chain, lysozyme and alpha 1 antitrypsin. On the basis of immunoglobulin and J chain content, the 11 cases fell into 4 groups. Staining for lysozyme and alpha 1 antitrypsin revealed a large variation in the staining intensity and numbers of reactive histiocytes between cases, although no positive staining of lymphoma cells was found. The results indicate that 64 per cent of the lesions were of B lymphocyte origin with no proven cases of true histiocytic lymphoma and are consistent with similar studies of nodal lesions.