ALK and T-cell non-Hodgkin lymphoma: As summarized in Table 1, they form a heterogeneous group of CD30-positive T cell non-Hodgkin lymphomas according to their site of onset (systemic, cutaneous or breast implant-associated) and their genetic features, with several groups according to the presence of ALK rearrangement and subsequent ALK expression defining ALK-positive or ALK-negative ALCLs [2,3,4].