Malignant lymphomas in patients with autoimmune diseases: a report of 6 cases and a review of the Japanese literature.

Six patients with malignant lymphomas in autoimmune diseases are described. Four patients who had Sjögren's syndrome (SS) alone or with progressive systemic sclerosis (PSS) or rheumatoid arthritis (RA) developed non-Hodgkin's lymphomas of the B cell type. One patient who had systemic lupus erythematosus (SLE) developed a B cell lymphoma. Another patient with chronic thyroiditis (ChTD) and idiopathic thrombocytopenic purpura (ITP) had a T cell (OKT3/T4) lymphoma. In 5 patients, the autoimmune diseases (2SS, SS/PSS, SS/RA and SLE) preceded B cell lymphomas by one to 11 years. In the patient with ChTD/ITP, ChTD and a malignant lymphoma were found simultaneously. A review of Japanese reports on lymphoproliferative disorders associated with these autoimmune diseases is given. This report offers the suggestion that disorders in the immunoregulatory system caused by autoimmune diseases may predispose lymphoproliferative disorders.