Background & Objectives: Myeloid/lymphoid neoplasms (MLNs) with eosinophilia and gene rearrangement are rare diseases characterised by myeloid and/or lymphoid proliferation, eosinophilia, and a fusion gene with constitutive tyrosine kinase (TK) activity. These disorders are responsive to TK inhibitors (TKIs) excluding FGFR1-rearranged MLNs, for which there is currently no standardised therapy. The aim of this study is to report 7 cases of MLNs collected from 2003 to 2018. Methods: All patients underwent bone marrow (BM) core biopsy that showed hypercellular BM, hyperplasia of eosinophilic granulopoiesis and features of myeloproliferative neoplasms (MPNs). In 4 out of 7 patients with lymphadenopathy, excisional lymph node biopsy was performed revealing a T-lymphoblastic lymphoma (T-LBL). Gene rearrangement was assessed with cytogenetic and/or molecular analysis. Results: In 6 out of 7 cases, the fusion gene has been identified: FIP1L1-PDGFRA (2/7), ETV6-PDGFRB (2/7) and ZMYM2-FGFR1 (2/7). In one case, no currently known TK fusion genes were recognized. Two PDGFRA-rearranged patients (one with MPN+T-LBL), two PDGFRB-rearranged patients, one FGFR1-rearranged patient (MPN+T-LBL) and the one with unidentified rearrangement (MPN+T-LBL) were treated with imatinib: all achieved complete hematologic remission except the FGFR1-rearranged patient. The other FGFR1-rearranged patient (MPN+T-LBL) was treated with polychemotherapy and allogeneic transplantation followed by relapse. Conclusion: Our cases confirm responsiveness of PDGFRA/B-rearranged MLNs to imatinib and possible existence of not yet known fusion TKs, which may benefit from TKIs. Identification of LBL in MLNs avoids overtreatment/nonresponse to intensive chemotherapy recommended in LBL. FGFR1-rearranged MLNs exhibit poor prognosis without an effective targeted treatment. Recently, pemigatinib, a selective, potent inhibitor of FGFR1, has shown promising results.
PS-07-016 Myeloid/lymphoid neoplasms with eosinophilia and gene rearrangement: a report of 7 cases
D. Fanni;G. Faa;
2019-01-01
Abstract
Background & Objectives: Myeloid/lymphoid neoplasms (MLNs) with eosinophilia and gene rearrangement are rare diseases characterised by myeloid and/or lymphoid proliferation, eosinophilia, and a fusion gene with constitutive tyrosine kinase (TK) activity. These disorders are responsive to TK inhibitors (TKIs) excluding FGFR1-rearranged MLNs, for which there is currently no standardised therapy. The aim of this study is to report 7 cases of MLNs collected from 2003 to 2018. Methods: All patients underwent bone marrow (BM) core biopsy that showed hypercellular BM, hyperplasia of eosinophilic granulopoiesis and features of myeloproliferative neoplasms (MPNs). In 4 out of 7 patients with lymphadenopathy, excisional lymph node biopsy was performed revealing a T-lymphoblastic lymphoma (T-LBL). Gene rearrangement was assessed with cytogenetic and/or molecular analysis. Results: In 6 out of 7 cases, the fusion gene has been identified: FIP1L1-PDGFRA (2/7), ETV6-PDGFRB (2/7) and ZMYM2-FGFR1 (2/7). In one case, no currently known TK fusion genes were recognized. Two PDGFRA-rearranged patients (one with MPN+T-LBL), two PDGFRB-rearranged patients, one FGFR1-rearranged patient (MPN+T-LBL) and the one with unidentified rearrangement (MPN+T-LBL) were treated with imatinib: all achieved complete hematologic remission except the FGFR1-rearranged patient. The other FGFR1-rearranged patient (MPN+T-LBL) was treated with polychemotherapy and allogeneic transplantation followed by relapse. Conclusion: Our cases confirm responsiveness of PDGFRA/B-rearranged MLNs to imatinib and possible existence of not yet known fusion TKs, which may benefit from TKIs. Identification of LBL in MLNs avoids overtreatment/nonresponse to intensive chemotherapy recommended in LBL. FGFR1-rearranged MLNs exhibit poor prognosis without an effective targeted treatment. Recently, pemigatinib, a selective, potent inhibitor of FGFR1, has shown promising results.
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