Angio-immunoblastic lymphadenopathy (AIL) or T-cell malignant lymphoma of AIL-type. A histopathological, immunohistochemical and ultrastructural study of 8 cases.

Eight cases of AIL-type T-cell malignant lymphoma are reported. The clinical symptoms are the same as those described in AIL: fever, malaise, weight loss, skin rashes, polyadenopathy, and splenomegaly. However, some differences can be noted: the absence of hepatomegaly in all cases but one, the absence of polyclonal hypergammapathy in all cases but one, and predominance in females. The lymph node modifications comprise diffuse infiltrations of lymphoid cells with irregular nuclei and pale cytoplasm, associated with a large number of immunoblasts and plasma cells. Some eosinophilic granulocytes and epithelioid cells can be seen. Hyperplasia of the vessels and remnants of follicles, sometimes with proliferation of follicular dendritic cells, are prominent features. The immunolabelling study demonstrates the presence of an important T-cell population all expressing a high predominance of CD 4 phenotype. These findings are in accordance with those published in Europe and in contrast with those of some of the Japanese cases, particularly the first patients published by Shimoyama et al. The differential diagnosis with AIL is based on the presence of clusters of mainly large cells with a pale cytoplasm, on the loss of expression of one T cell marker, as in 3 cases of our series, and on the presence of a high percentage of lymphoid cells engaged in the mitotic cycle as demonstrated with the Ki 67 monoclonal antibody. However, to draw a clear cut difference between AIL-type T-cell lymphoma and AIL considered as a prelymphomatous dysimmune lymphadenopathy, only the demonstration of cytogenetic abnormalities, as in one of our cases or of rearrangement of the genes coding for beta and/or gamma chain of the antigen receptor of T-cell are valuable criteria. The follow-up of our series is not long enough to appreciate the prognosis. Three patients died, one from a glioma. All the other cases, treated with polychemotherapy show total remission with an evolution of 10 to 39 months.