Cytoplasmic immunoglobulins in giant lymph node hyperplasia (Castleman's tumour)

The immunohistologic features were studied in 6 cases of giant lymph node hyperplasia (GLNH) and the cytoplasmic immunoglobulin (CIg) characteristics were compared with those of follicular lymphoma and non-specific follicular lymph node hyperplasia. By use of the peroxidase - antiperoxidase (PAP) technique it was shown that GLNH comprised a mosaic, polyclonal population of CIG-producing cells, the CIg pattern being comparable with that observed in follicular lymphadenitis. In contrast, follicular lymphomas disclosed a definite monoclonal pattern, the cytoplasmic Ig containing only one light chain of kappa type. This led to the conclusion that GLNH is not a neoplastic change, but has the characteristics of a reactive process within the B-cell compartment.