[FIP1L1/PDGFRalpha fusion gene-negative chronic eosinophilic leukemia with t(5;12)(q31;p13): a case report and review of literatures].

OBJECTIVE: To deepen the understanding of chronic eosinophilic leukemia (CEL). METHODS: The course of diagnosis and treatment in a case of FIP1L1/PDGFRalpha fusion gene negative CEL was reported. Flow cytometry was used to analyze the immunophenotype of the cells in peripheral blood and pleural fluid. Karyotype was analyzed with G-banding. The expression of FIP1L1/PDGFRalpha fusion gene was detected by RT-PCR technique. Routine pathological examination of the tissues from bone marrow, lung and spleen were performed. RESULT: A sixteen-year-old girl had severe anemia, fever, splenomegaly, thrombocytopenia and dominant hypereosinophilia lasting for 22 months. Trephine biopsy showed a hypercellular marrow with eosinophilic proliferation and moderate reticular fibrosis. Eosinophilic infiltration was found in lung and spleen and embolism was also found in spleen. She had a clonal chromosomal abnormality t(5;12)(q31;p13). The expression of FIP1L1/PDGFRalpha was negative. An abnormal clone of T cells expressing CD(3)(-), CD(4)(-), CD(8)(+) was found in peripheral blood and pleural fluid, in which the clonal T cell accounted for 5.43% and 1.66% of the total lymphocytes respectively. The patient was refractory to treatment with hydroxyurea, prednisone and interferon alpha. She had poor response to a combination of therapy with low dose cytosine arabinoside, mitoxantrone, vincristine, cyclophosphamide, methotrexate and prednisone. She did not respond to imatinib and died of multiple organ failure. CONCLUSION: The present case fulfilled the WHO diagnostic criteria of FIP1L1/PDGFRalpha(-) CEL which did not respond to routine treatment and imatinib. Allogenic stem cell transplantation should be considered as early as possible in this case. It is noteworthy that clonal CD(3)(-), CD(4)(-), CD(8)(+)T-cell abnormality is related to the pathogenesis of CEL.