Gamma-delta T-cell lymphomas are very rare and aggressive T-cell neoplasms with complex heterogenicity and diagnostic complexity. Gamma-delta T lymphocytes 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: hepatosplenic Tγδ lymphoma (HSγδTL), primary cutaneous gamma-delta TCL (PCTCL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) and large granular 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.
Part of the book: Peripheral T-cell Lymphomas