Lymphomatoid granulomatosis--a report on four cases: evidence for B phenotype of the tumoral cells.

Four cases of lymphomatoid granulomatosis are reported, three of them involving the lung. Histological features included a true angiocentric and angiodestructive polymorphic cellular proliferation. This included histiocytes, plasma cells, many reactive T-cells and rare large, atypical cells which were of the B phenotype. Epstein-Barr virus was detected in the atypical cells by in situ hybridization in three cases, with expression of both latent membrane proteins (LMP)-1 and Epstein-Barr nuclear antigen-2 in two cases and expression of only LMP-1 in the third case. Expression of both of these proteins suggests a defect in the T-cell-mediated immunity and that Epstein-Barr virus is not only a silent passenger but may also be involved in the pathogenesis of the disease. This could have implications for therapy.