Ki-1-positive lymphoma developing 10 years after the diagnosis of hairy cell leukemia.

The case is described of a 62-year-old man with a 10-year history of hairy cell leukemia (HCL) who subsequently had a large-cell anaplastic or so-called Ki-1-positive lymphoma. Immunocytochemical staining of the lymphomatous node revealed positivity for Ki-1 (CD30) and epithelial membrane antigen in the tumor cells, and flow cytometric analysis showed simultaneous expression of Leu M5 (CD11c) and Leu 14 (CD22). Although HCL has been reported to coexist with both Hodgkin's disease and non-Hodgkin's lymphoma, the authors believe this is the first case in which a Ki-1-positive lymphoma developed in a patient with HCL. The clinicopathologic and immunologic features of both entities are discussed, as is the association of HCL with other neoplasms.