[Reactive hyperplasia and pseudo-lymphomas with hypergammaglobulinemia. I. Benign lymphadenopathies].

The association of adenopathies, having sometimes a tumoral aspect, and a polyclonal hypergammaglobulinemia in the blood can be observed in various illnesses. In all these diseases the increase in the volume of the lymph nodes is partly due to the hyperplasia of the lymphoid B regions. Lymph node biopsy allows a precise diagnosis to be made, providing a thorough analytical study of the histopathological lesions is performed. In this first part, the histopathological lesions of benign lymphadenitis, having a pseudo-tumoral aspect from a clinical view, are described. The following are thus successively studied: sarcoidosis; acquired toxoplasmosis; the various aspects which can be attributed to infectious mononucleosis; vaccinal reactions; the Destombes-Rosai-Dorfman syndrome or massive lymphadenopathy by sinusal histiocytosis with hemophagocytosis; angiofollicular lymphoid hyperplasia or pseudo-tumour of Castleman; angio-follicular and plasmocytic polyadenopathy; the adenopathies of collagenosis and those due to protein deposits. For each disease, the morphological data are discussed and compared to clinical state and biological modifications.