We report 5 cases of peripheral T cell lymphoma (PTCL) which initially presented as angioimmunoblastic lymphadenopathy (AIL). In 4 cases, the delay between the 2 phases was less than 1 year, and 3 patients were under corticosteroid therapy when the second biopsy was performed. Clinical and biological features were very similar during the 2 phases. The initial disease was morphologically characterized by a high cellular pleomorphism with immunoblasts, plasma cells, eosinophils and lymphoid cells of various size with abundant venules; this pleomorphism then regressed, emphasizing the T cell nature of the lymphoma, as proven by immunological staining with monoclonal antibodies raised against T cell subpopulations. In 4 cases, T cell proliferation bore T helper (CD4) and T cytotoxic/suppressor (CD8) antigens and, in 1 case only, CD4 antigen. The entity of AIL and the role of corticosteroid therapy is discussed; the short interval between the 2 diagnose suggests that T cell proliferation was present initially, but was masked by reactive B lymphocytes.