γδ T-Cell Acute Lymphoblastic LeukemiaLymphoma: Discussion of Two Pediatric Cases and Its Distinction from Other Mature γδ T-Cell Malignancies

Abstract EN

Gamma delta (γδ) T-cell antigen receptor (TCR) expression and its related T-cell differentiation are not commonly reported in T-cell acute lymphoblastic leukemia/lymphoma (T-ALL).

Here we report two pediatric T-ALL cases and present their clinical features, histology, immunophenotypes, cytogenetics, and molecular diagnostic findings.

The first patient is a two-year-old girl with leukocytosis, circulating lymphoblasts, and a cryptic insertion of a short-arm segment at 10p12 into the long-arm segment of 11q23 resulting in an MLL and AF10 fusion transcript, which may be the first reported in γδ T-ALL.

She responded to the chemotherapy protocol poorly and had persistent diseases.

Following an allogeneic bone marrow transplant, she went into remission.

The second patient is an eleven-year-old boy with a normal white cell count, circulating blasts, and a normal karyotype, but without any immature cellular markers by flow cytometric analysis.

He responded to the chemotherapy well and achieved a complete remission.

These cases demonstrate the diverse phenotypic, cytogenetic, and molecular aspects of γδ T-ALL.

Early T-precursor- (ETP-) ALL and their differential diagnosis from other mature γδ T-cell leukemia/lymphomas are also discussed.