Acute promyelocytic leukemia with t(15;17) abnormality after chemotherapy containing etoposide for langerhans cell histiocytosis

Background. Epipodophyllotoxins, etoposide and teniposide, have been shown to be implicated in the development of acute myelogenous leukemia in patients treated for solid tumors or acute lymphoblastic leukemia. Etoposide has been shown to be an effective agent against Langerhans cell histiocytosis (LCH) and has gained wider use recently for first‐line and salvage chemotherapy in cases of systemic LCH. Methods. The authors report two patients with secondary acute promyelocytic leukemia (APL) with a t(15;17) abnormality after chemotherapy that included etoposide for the treatment of LCH. Results. Patient 1, a 6‐year‐old girl, had APL develop 11 months after cessation of therapy that included vinblastine, prednisolone, and etoposide (9600 mg/m2 in total dose) for LCH. Patient 2, a 3‐year‐old girl, had APL develop 9 months after cessation of therapy that included vincristine, methotrexate, prednisolone, cyclophosphamide (10,800 mg/m2), and etoposide (4800 mg/ m2) for LCH. Conclusions. The authors have experience with four patients treated with etoposide for LCH and suggest that there is a predisposition to secondary APL with t(15;17) for patients with LCH treated with etoposide. The authors warn against the imprudent use of etoposide as a first‐line therapy for LCH.