Novel LUC7L::NUTM1 fusion in PDGFRA-rearranged myeloproliferative neoplasm with eosinophilia: a case report.

Myeloid/lymphoid neoplasm with PDGFRA rearrangement are a group of haematologic tumors, in which the clonal proliferation of precursor eosinophils leads to persistent eosinophilic hyperplasia, and varying degrees of involvement of the liver, spleen and lymph nodes. While PDGFRA rearrangements are frequently observed in mpn-eo, the co-occurrence of t(15;16)(q14;p13) translocations leading to LUC7L::NUTM1 fusion genes has not been previously documented. Here we present a 30-year-old male patient with leukocytosis and generalized lymphadenopathy. Bone marrow cytology revealed eosinophilia with abnormal and atypical granulocytes showing dysplastic cytoplasmic granules. Cytogenetic analysis identified t(15;16)(q14;p13), while RNA sequencing confirmed the novel LUC7L::NUTM1 fusion gene and co-detected FIP1L1::PDGFRA fusion gene. The patient achieved stable disease imatinib (100 mg/day) treatment. This first report of dual PDGFRA/NUTM1 fusions expands the molecular spectrum of MPN-Eo and highlights the therapeutic implications of novel fusion detection.