Clonal Hypereosinophilia with ETV6 Rearrangement Evolving to T-Cell Lymphoblastic Lymphoma: A Case Report and Review of the Literature

Abstract

Hypereosinophilia, either clonal or reactive, has been described in association with multiple hematological malignancies. We describe a case of a patient presenting with hypereosinophilia that evolved into T-cell lymphoblastic lymphoma. Complete remission was achieved with chemotherapy; however, hypereosinophilia recurred 5 months later in association with myeloblastic bone marrow infiltration and without evidence of lymphoblastic lymphoma relapse. Cytogenetic analysis of the bone marrow showed a complex translocation involving chromosomes 7, 12, and 16. A rearrangement of ETV6 gene (12p13) was demonstrated by FISH studies, thus confirming the clonality of this population. The association of lymphoblastic lymphoma, eosinophilia, and myeloid hyperplasia has been described in disorders with FGFR1 rearrangements. We hypothesize that other clonal eosinophilic disorders lacking this rearrangement could behave in a similar fashion through different pathogenic mechanisms.

Figure 1

Bone marrow aspirate at relapse showing infiltration by myeloblasts, left shifted granulopoiesis, and marked hypereosinophilia.

Figure 2

Cytogenetics of the patient's bone marrow (a) G-banded karyotype showing 46,XX,t(7;12)(q22;p13),add(16)(p13); (b) fluorescence in situ hybridization using a dual-color break-apart probe showing rearrangement of ETV6 (12p13) (c) whole chromosome painting of chromosomes 7 (red) and 12 (green) showing 46,XX, del(7)(q22),der(12)t(7;12)(q22;p13)t(12;16)(p13;p13);der(16)t(12;16).