ACUTE-LEUKEMIA IN ASSOCIATION WITH LANGERHANS CELL HISTIOCYTOSIS

Langerhans cell histiocytosis (LCH) and malignancy occurring in the sa me individual is unusual and has generally been the subject of isolate d case reports. To better define the occurrence of these events a regi stry of cases with synchronous or asynchronous LCH and malignancy was developed with the cooperation of the Histiocyte Society. In 1991 the Histiocyte Society surveyed its members requesting information on case s in which LCH was associated with malignancy. The questionnaire was m ailed to all members of the society and specifically requested informa tion on the clinical and laboratory features of the cases, disease evo lution, and response to therapy. Retrospective reporting was allowed. With this initial data, an ongoing registry of LCH patients with assoc iated malignancy was begun of such cases, including evolution and resp onse to therapy. Twenty-seven patients were enrolled during the first year of the registry, of whom 4 patients had the association of LCH wi th a malignant lymphoma and 10 cases had an association of LCH with ot her types of solid tumor. The remaining 13 patients had the associatio n of LCH with acute leukemia. In five cases, LCH was associated with a cute lymphoblastic leukemia FAB Ll (ALL). In four cases the ALL preced ed the LCH by 6 months to 1 year. In four of five patients the LCH was localized; in two instances the LCH was treated with chemotherapy. In all cases the leukemia was treated according to local standard ALL pr otocols and in one case autologous bone marrow transplantation (ABMT) was performed at relapse. Three patients are free of leukemia, one of whom has persistent localized LCH of the skin. Two patients died of th e ALL, one of whom was free of the LCH at the time of death. In eight instances LCH was reported in association with acute myeloid leukemia (AML). Six of these patients had a generalized form of LCH. In seven t he diagnosis of LCH preceded the diagnosis of leukemia by more than 2 years (median 4 years). In the remaining patient both diagnoses were m ade concurrently. In all seven cases in whom LCH was the initial diagn osis the treatment consisted of chemotherapy and/or radiotherapy. Seve n patients died from the AML, five without evidence of LCH. The tempor al patterns of the LCH-ALL and LCH-AML associations are distinct with ALL usually preceding the diagnosis of LCH and AML succeeding it. Such a pattern is suggestive that in cases of ALL the LCH may be a reactiv e process while in cases of AML occurring after LCH the primary LCH th erapy may play an inductive role in the leukemia. (C) 1994 Wiley-Liss, Inc.