Dear Editor, A 24-year-old woman was seen in the rheumatology clinic because of a left wrist monoarthritis in January 2001. Her blood analysis showed: hemoglobin 136 g/dl, leukocytes 7.1× 10/l, eosinophils making up 81% of all leukocytes, and platelets 159×10/l. Immunocytometry showed that 4% of all leukocytes in the peripheral blood were an abnormal lymphocyte population of CD3−, CD4+, CD2+, and CD7+. Karyotype of blood and bone marrow was 46XX. T cell receptor (TCR) beta and gamma rearrangements were clonal and FIPL1/PDGFα rearrangement was negative. Bone marrow showed hypereosinophilia; no dysplastic morphology was found and blastic population did not reach 1% of all nucleated bone marrow cells. A left axillary lymphadenopathy of 1.5 cm grew in February 2002. A pathological review diagnosed it as a non-Hodgkin’s peripheral T lymphoma. Computer tomography of the thorax and pelvis only showed a spleen of 15 cm and no lymphadenopathies. Bone marrow biopsy did not show infiltration by lymphoma. The patient was treated with four cycles of Mega CHOP (cyclophosphamide 1,500 mg/m, doxorubicin 50 mg/m, vincristine 2 mg/m, and prednisone 60 mg/m) every 21 days. After four cycles of treatment, abnormal CD3−/ CD4+ lymphocytes with eosinophilia persisted in blood. Despite this fact, the patient was in good health and without clinical progression. In March 2004, an echocardiogram disclosed an extensive hyperechogenic lesion that occupied half of the right ventricle and also the left ventricle. Endomyocardial biopsy of the right ventricle showed an extensive thrombus, eosinophilic infiltration of the myocardium, and no lymphoma. The patient was treated with fractionated heparin and corticoids, but 2 months later, another echocardiogram showed that only a third of the right chamber was free. The patient has an HLA identical brother. Reduced intensity peripheral blood stem cell transplantation was performed in November 2004. The cardiac ejection fraction was 60% and the patient had no symptoms of heart failure. Conditioning regimen consisted in fludarabine 25 mg/m× 5 days and melphalan 80 mg/m on day −1. Peripheral blood CD34 infused was 4.9×10. Graft versus host prophylaxis included a short course of metrotrexate (5 mg/m on days 1, 3, 6, and 11) and cyclosporine (for 6 months). Grade II GVHD consisting of rash and diarrhea occurred on day +23; it was treated with a short course of corticoids. Veno-occlusive disease (VOD) occurred on +12 day after stem cell infusion. Defibrotide was administered to treat VOD for 16 days. Neutrophil count was normal on +35 day and eosinophilia disappeared from the blood. Platelet count was normal a year after transplantation. FISH determination of chromosome Y at this time Ann Hematol (2008) 87:937–938 DOI 10.1007/s00277-008-0505-9