Chronic eosinophilic leukemia with t(6;11)(q27;q23) translocation

We report a rare case of chronic eosinophilic leukemia (CEL) with a chromosomal abnormality of t(6;11)(q27;q23). The patient was diagnosed as having thyroid cancer with metastases to the lung and cervical lymph nodes in 1993. Percutaneous ethanol injection therapy (PEIT), total thyroidectomy, and radiotherapy were performed. The patient was also diagnosed as having prostatic cancer with bone metastasis in July 1999, and hormonal therapy was performed. At the time of the diagnosis of prostatic cancer, leukocytosis with eosinophilia was also revealed. Thereafter, cytogenetical analysis and reverse transcriptase polymerase chain reaction (RT-PCR) analysis of bone marrow showed t(6;11)(q27;q23) translocation and MLL/AF6 fusion products, respectively. No transcripts of the BCR/ABL chimeric gene were found by RT-PCR in bone marrow. Analysis of serum cytokines revealed a slight elevation of GM-CSF but no elevation of IL-3 or IL-5. Tissue damage due to infiltration of eosinophils was not observed throughout the clinical course. On the basis of the cytogenetic and molecular abnormality, the patient was diagnosed as having CEL, rather than reactive eosinophilia due to thyroid or prostatic cancer or other reactive inflammation. This is the first case report of CEL with t(6;11)(q27;q23) translocation.