8p11 myeloproliferative syndrome with t(1;8)(q25;p11.2): a case report and review of the literature.

8p11 myeloproliferative syndrome (EMS) is a rare disease characterized by myeloproliferative neoplasm (MPN) associated with eosinophilia and T or B lymphoblastic lymphoma/leukemia. EMS is defined by molecular disruption of the FGFR1 gene at the 8p11-12 chromosome locus, and various partner genes are associated with FGFR1 gene translocation or insertion. The different partner-FGFR1 fusion genes are associated with slightly different disease phenotypes. The present patient showed T lymphoblastic lymphoma in a cervical lymph node, involvement of malignant lymphoma in the skin, and MPN bone marrow morphology with peripheral monocytosis. Chromosome analysis of the patient showed t(1;8)(q25;p11.2). To our knowledge, only 2 cases of EMS with translocation of t(1;8)(q25;p11.2) have been previously reported. Including this case, all 3 cases with EMS with t(1;8)(q25;p11.2) showed MPN bone marrow morphology and peripheral monocytosis. These findings support that t(1;8)(q25;p11.2) is associated with peripheral monocytosis in EMS patients. Of the 2 cases of EMS with t(1;8)(q25;p11.2) which were previously reported, FGFR1 rearrangement was not confirmed in 1 case. Similarly, FGFR1 rearrangement in the present case was not detected by fluorescence in situ hybridization or reverse transcription-polymerase chain reaction. Further study is needed to identify other techniques that could be used to demonstrate FGFR1 rearrangement.