This is the first description of a patient with a BCR-FGFR1 MPN presenting with B-ALL who has undergone allogeneic HSCT: three previously described patients presenting with either an atypical MPN or a T-lymphoblastic lymphoma all achieved a complete remission and were alive at last reported followup after allogeneic HSCT. Here, FGFR1 is linked to T-lymphoblastic lymphoma.