[Acute lymphoblastic leukemia in a pediatric patient with Marfan's syndrome].

We report a rare case of acute lymphoblastic leukemia (ALL) in a 7-year-old boy with Marfan's syndrome. He was diagnosed as having Marfan's syndrome by clinical findings at the age of 2 years, and the diagnosis was confirmed by the detection of gene mutation in FBN1. He was referred to our hospital because of the swelling of cervical lymph nodes at the age of 7 years. Findings on bone marrow examination demonstrated T lymphoblastic ALL. He obtained complete remission after induction therapy, and had no serious side effects including cardiotoxicity during chemotherapy. He has remained in continuous complete remission for 34 months following diagnosis. To our knowledge, only three cases of leukemia in patients with Marfan's syndrome were reported previously. We speculate that increased activity of TGF-β, which is known as a tumor suppressor factor, in patients with Marfan's syndrome may diminish the risk of developing leukemia, although such a thesis was not proven in this case.