A Challenging Case of Gamma Delta T-Cell Lymphoma with Precursor T-Cells and Marked Eosinophilia: A Case Report.

Gamma-delta (γδ) T-cell lymphomas are very rare and aggressive neoplasms. We describe here a challenging case of γδ T-cell neoplasm composed of γδ mature T-cells and γδ precursor T-cells with marked eosinophilia that is inapplicable to the current 2016 World Health Organization (WHO) classification. A 3-year-old female child who was presented with fever and marked leukocytosis. Peripheral blood smear showed marked lymphocytosis, marked eosinophilia, neutrophilia, monocytosis, and 5% circulating blasts. CT scan showed anterior mediastinal mass, lymphadenopathy, and hepatosplenomegaly. The patient underwent a bone marrow examination and a biopsy taken from the mediastinal mass. Peripheral blood and bone marrow findings were consistent with a γδ T-cell neoplasm with increased blasts and eosinophilia. The patient was sequentially treated with imatinib (tyrosine kinase inhibitor), acute lymphoblastic leukemia protocol (BFM 2009) then shifted to lymphoma protocol (LMP 96). In conclusion, we report a unique rare case of γδ T-cell neoplasm with a combination of mature and immature γδ T-cells and eosinophilia that is inapplicable to the current 2016 WHO classifications. This case raises a challenging concept of a mature T-cell lymphoma arising in an immature T-cell neoplasm. It also highlights the need to target all neoplastic components to eradicate the disease.