Transformation of hairy cell leukemia to EBV genome-containing aggressive B cell lymphoma.

Hairy cell leukemia is a preplasmacytic B cell leukemia which is not EBV associated, although elevated titers of Epstein-Barr virus (EBV) antibodies have been seen in this leukemia and chronic lymphocytic leukemia. Hairy cells are not readily susceptible to EBV infection in vitro, even though they are EBV receptor-positive B cells. We have observed a 59-year-old patient who after 9 years of hairy cell leukemia developed a well-differentiated IgG-kappa monoclonal B cell lymphoma without further evidence of hairy cell leukemia.

Chloroma (granulocytic sarcoma) without evidence of leukemia: facilitated light microscopic diagnosis.

Localized tumors composed of immature cells of the myelogenous series have been recognized for many years as an uncommon manifestation of granulocytic leukemia. The histologic diagnosis of chloroma (granulocytic sarcoma) may be extremely difficult when the myeloblastic cells are poorly differentiated and the tumor lacks the characteristic green color. The diagnostic difficulty may be further compounded when the granulocytic sarcoma develops before there is peripheral blood or bone marrow evidence of leukemia.