Sezary syndrome in a patient with hairy cell leukemia in remission

: A 65-year-old man was evaluated for pancytopenia in March 1979, and found to have hairy cell leukemia (HCL). Treatment with splenectomy and subsequently interferon produced temporary remissions. In July 1985, the patient began intravenous deoxycoformycin (DCF) therapy, and after 1 year complete peripheral blood and bone marrow remission was achieved. Fourteen months after cessation of therapy, the patient developed a skin rash and was found to have cutaneous T-cell lymphoma and Sezary syndrome. Morphologic study of the hairy cells (HC) in the peripheral blood at presentation and the Sezary cells was distinct by light and electron microscopic study. Immunophenotyping of peripheral blood mononuclear cells showed clearly that the HC were of B-cell origin (CD20+, sIg+), whereas the lymphoid population at second presentation was T-cell (CD3+, CD4+, HLA-DR-). Clonal rearrangement of T-cell antigen receptor beta-chain gene was detected by Southern analysis of the Sezary cell population, whereas immunoglobulin heavy and light chain genes remained in germ line configuration. This is the first case of Sezary syndrome developing in a patient previously treated for HCL where studies have confirmed distinct B-cell and T-cell origin of the two neoplasms. The authors suggest that treatment and disease-related immunosuppression are possible etiologic factors in the development of this second lymphoid neoplasm.