Hematopoietic neoplasms with FGFR1 rearrangements are rare. Clinically, patients often present with a chronic myeloproliferative neoplasm with eosinophilia and an increased risk of transformation to acute leukemia. We report a patient who initially presented with B-cell acute lymphoblastic leukemia (B-ALL) with t(8;22)(p11.2;q11.2) and an additional derivative chromosome 22 [der(22)t(8;22)]. After induction chemotherapy, B-ALL blasts were eradicated; however, a chronic myeloproliferative process emerged showing persistent t(8;22) (p11.2;q11.2) but not der(22)t(8;22). Combined morphologic and fluorescence in situ hybridization revealed that both lymphoblasts and myeloid cells harbored t(8;22)(p11.2;q11.2); but only lymphoblasts carried the additional der(22)t(8;22). This case provides direct evidence to illustrate the clonal relationship of chronic phase and blast phase in myeloid neoplasms with FGFR1 rearrangement, and demonstrates that clonal cytogenetic evolution plays an important role in disease progression.
Wei Wang, Guilin Tang, Tapan Kadia, Xinyan Lu, Yan Li, Lanshan Huang, Ximena Montenegro-Garreaud, Roberto N. Miranda and Sa A. Wang
Sanjeev Kumar Gupta, Nitin Jain, Guilin Tang, Andrew Futreal, Sa A. Wang, Joseph D. Khoury, Richard K. Yang, Hong Fang, Keyur P. Patel, Rajyalakshmi Luthra, Mark Routbort, Bedia A. Barkoh, Wei Chen, Xizeng Mao, Jianhua Zhang, L. Jeffrey Medeiros, Carlos E. Bueso-Ramos and Sanam Loghavi
RNA-seq was used to identify the partner gene and confirm the presence of a BCR-PDGFRB fusion. Identification of this fusion product resulted in successful treatment and long-term remission of this myeloid neoplasm. Based on our results, we suggest that despite current WHO recommendations, screening for PDGFRB rearrangement in cases of leukocytosis with eosinophilia and no other etiologic explanation is necessary, even if the karyotype is normal.