Myeloid or lymphoid neoplasms with FGFR1 abnormalities

**Definition:** Hematologic neoplasms characterised by the rearrangement of the FGFR1 gene, resulting in translocations with an 8p11 breakpoint. Patients may present with a myeloproliferative neoplasm, acute myeloid leukaemia, lymphoblastic lymphoma/leukaemia of T or B-cell lineage, or acute leukaemia of mixed phenotype.