ALK and peripheral T-cell lymphoma, not otherwise specified: Peripheral T cell lymphomas (PTCL) encompass a heterogeneous group of neoplasm derived from T cell lineages and represent ~10–15% of non-Hodgkin lymphoma1, mainly including anaplastic large-cell lymphoma (ALCL)-anaplastic lymphoma kinase (ALK)-positive (ALK+ALCL), ALCL-ALK-negative (ALK−ALCL), angioimmunoblastic T cell lymphoma (AITL), and PRCL-not otherwise specified (PTCL-NOS)2.