Immunoglobulin production in lymphomatoid granulomatosis and relation to other "benign" lymphoproliferative disorders

Immunoperoxidase technics were used to examine the immunoglobulin content of sections of pulmonary tissue from two typical cases of lymphomatoid granulomatosis and two cases of pneumonic processes initially diagnosed as lymphomatoid granulomatosis but representing different processes on review. Both "typical" cases and one of the others had a predominantly mixed pattern of all immunoglobulins. One "typical" case showed a focus of exclusively IgG/K staining, which corresponded to histologic malignancy. Less than 1% of cells stained in the fourth case. These results demonstrate that several different processes may fit the morphologic criteria of lymphomatoid granulomatosis; that there is a group of cases that typify lymphomatoid granulomatosis clinically and histologically, and that these cases represent a B-cell proliferation that is initially polyclonal but may evolve into immunoblastic sarcoma. "Typical" cases are similar to other lymphoreticular proliferations with malignant potential, such as angioimmunoblastic lymphadenopathy and Sjögren's syndrome.