มะเร็งเม็ดเลือดขาวเรื้อรังชนิดมัยอีลอยด์ที่มีการกลับเป็นซ้ำของโรคเฉพาะ ในระบบประสาทภายหลังการปลูกถ่ายไขกระดูก

Abstract

Hematopoeitic stem cell transplantation (HSCT) is considered one of the curative treatments for chronic
myeloid leukemia (CML), a rare hematologic malignancy in pediatric populations. A 5–year-old boy presented
fever and hepatosplenomagaly and received a diagnosis of chronic phase CML. His initial CBC showed anemia
(Hb 7.8 g/dL) and hyperleukocytosis (WBC 152 x103/mm3: Neu 30, Ly 43, Mo 5, Eo 0, Ba 5, myeloblast 1, promyelocyte 1, metamyelocyte 4, band form 10 and myelocyte 1%) and normal platelet count (platelet 378,000/mm3). A bone marrow aspiration was compatible with CML in the chronic phase. Karyotype analysis of the bone marrow revealed 46,XY, t(9,22). He was treated with hydroxyurea (500 mg/day). Four months later, he progressed to myeloid blast crisis. Imatinib (Glevec®) 500 mg/day was administered. A repeated BMA and cytogenetic analysis revealed normal values 3 months after treatment. Five months later, he developed a 2nd episode of myeloid blastic crisis. He received an induction of remission chemotherapy with cytarabine plus idarubicin. He achieved a remission with normal CSF cytospin. After that, he underwent an allo-HSCT from an HLA-matched sibling donor, receiving busulfan and cyclophosphamide as conditioning regimen and cyclosporine and methotrexate as GVHD prophylaxis. He was in disease remission after HSCT. HwTwelve months after HSCT, he developed ataxia with normal CBC. A brain MRI revealed an infiltrative lesion sized 4x3x2 cm involving superior cerebellar vermis with leptomeningeal enhancement, and BM remained in remission. A biopsy of a cerebellar tumor revealed mixed phenotype comprising B lymphoblastic and myeloblastic. A spine MRI revealed leptomeningeal enhancement along the conus medullaris. Isolated central nervous system (CNS) relapse of mixed lymphoid and myeloid blasts was diagnosed. He received whole brain and spinal radiation with triple intrathecal chemotherapies. Currently, he is in remission 8 years after the relapse. Risk factors of isolated CNS relapse in our patient included conditioning regimen without total body irradiation, minimal CNS penetration of imatinib and weak graft vs. leukemia in the CNS. Treatment for this relapse has not yet been well defined. In summary, we describe the first report of isolated CNS relapse in a     patient undergoing HSCT for CML