FIP1L1‐PDGFRA fusion gene in T‐lymphoblastic lymphoma: A case report

BACKGROUND: T‐lymphoblastic lymphoma (T‐LBL) is an aggressive malignancy of T‐lymphoid precursors, rarely co‐occurring with myeloid/lymphoid neoplasms with eosinophilia (M/LNs‐Eo), with consequent rearrangement of tyrosine kinase (TK)‐related genes. The FIP1L1‐PDGFRA fusion gene is the most frequent molecular abnormality seen in eosinophilia‐associated myeloproliferative disorders, but is also present in acute myeloid leukemia (AML), T‐lymphoblastic leukemia/lymphoma (TLL), or both simultaneously. T‐LBL mainly affects children and young adults, involving lymph node, bone marrow, and thymus. It represents about 85% of all immature lymphoblastic lymphomas, whereas immature B‐cell lymphomas comprise approximately 15% of all cases of LBL. CASE: In this case report, we present an example of T cell lymphoblastic lymphoma with coexistent eosinophelia, treated successfully with a tyrosine‐kinase inhibitor (TKI). CONCLUSION: FIP1L1‐PDGFRA‐positive T‐LBL and myeloproliferative disorders have excellent response to low‐dose treatment with (TKI) imatinib. Most patients achieve rapid and complete hematologic and molecular remission within weeks.