8p11 myeloproliferative syndrome preceded by t(8;9)(p11;q33), CEP110/FGFR1 fusion transcript: morphologic, molecular, and cytogenetic characterization of myeloid neoplasms associated with eosinophilia and FGFR1 abnormality.

We report a rare case of t(8;9)(p11;q33) in a patient with 8p11 myeloproliferative syndrome (EMS) that was preceded by centrosomal protein 110kDa (CEP110; previously CEP1)/fibroblast growth factor receptor 1 (FGFR1) fusion transcript. A 36-year-old man was brought to Severance Hospital with a nasopharyngeal mass and eosinophilia. Biopsy of the left tonsil and nasopharynx revealed diffuse infiltration of atypical lymphoid cells, and he was diagnosed with precursor T-cell lymphoma with hypereosinophilic syndrome. Two months later, chromosome study revealed a 46,XY,t(8;9)(p11;q33) karyotype, and the CEP110/FGFR1 fusion transcript was detected by reverse transcription-polymerase chain reaction (RT-PCR) in both this and the previous bone marrow specimen. Timely molecular and cytogenetic tests are of value for diagnosis and treatment of the newly classified "myeloid neoplasms associated with clonal eosinophilic disorders" (according to 2008 World Health Organization criteria).