Gamma-Delta T-cell Lymphoma: An Overview

Abstract

Gamma-delta T-cell lymphomas are very rare and aggressive T-cell neoplasms with complex heterogenicity and diagnostic complexity. Gamma-delta T lympho-cytes originate from CD4− CD8− (double negative) thymocytes in the bone marrow and are distinct from alpha beta subtype. Four entities of gamma-delta lymphomas recognized by 2016 WHO classification of lymphoid neoplasms include: hepato-splenic Tγδ lymphoma (HSγδTL), primary cutaneous gamma-delta TCL (PCTCL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) and large granu-lar lymphocytic leukemias (T-LGL). Extensive literature search based on small case series and case reports identifies few more subtypes of gamma-delta T-lymphomas which were not previously classified by World Health Organization. There remains a critical gap in our understanding of the subtypes of gamma-delta T-cell lymphomas and a lack of updated summarization. In this review, we summarize in detail on the classification, biology, heterogenicity, diagnosis, clinical behavior and treatment options of these rare but clinically important entities.