Successful treatment and integrated genomic analysis of an infant with FIP1L1-RARA fusion-associated myeloid neoplasm.

FIP1L1-RARA associated neoplasm is a very rare and aggressive disease, with only 3 previously reported cases in the literature. Herein we describe a 9-month-old boy who presented with a FIP1L1-RARA fusion associated myelodysplastic/myeloproliferative (MDS/MPN) neoplasm-like overlap syndrome, with similarities and distinct features to both acute promyelocytic leukemia (APL) and juvenile myelomonocytic leukemia (JMML). Using a combined approach of chemotherapy, differentiating agents and stem cell transplantation (allo-HCT), this patient remains in remission 20 months after allo-HCT. To our knowledge, this is only the second published pediatric case involving this condition and the only case with a favorable long-term outcome. Given the aggressive disease described in the previously published case report, as well as the successful treatment course described herein, the combinatorial use of chemotherapy, differentiation therapy, and allogeneic HCT for treatment of FIP1L1-RARA fusion associated myeloid neoplasms, should be considered.