[Osteonecroses of the bilateral tali during maintenance therapy in a child with acute lymphoblastic leukemia]

We present a 12-year-old girl with acute lymphoblastic leukemia (ALL) complicated by osteonecroses of the bilateral tali. She was diagnosed as having ALL at 11 years old and was classified as extremely high risk ALL according to the criteria of Japan Association of Childhood Leukemia Study. She complained of pain around the bilateral ankles during maintenance therapy on 86-88 and 96-98 weeks. Magnetic resonance imaging study demonstrated osteonecroses of bilateral tali. Nonweight-bearing (crutches and wheelchair) over 1 year did not improve osteonecrotic lesions. She had all of the recently identified risk factors for osteonecrosis, including higher cumulative dose of corticosteroid, female gender, age over 10 years, and specific genetic polymorphisms (2/2 enhancer repeat genotype of thymidylate synthase, C/C genotype of vitamin D receptor start site). Early indication of ALL patients predisposed to genetic, treatment-related risk factors for osteonecrosis and appropriate preventive strategy for such patients await a further multicenter study in Japan.