ALK and mature T-cell and NK-cell non-Hodgkin lymphoma: They comprise different cutaneous, extranodal and nodal entities that are often referred to as peripheral T-cell lymphomas (PTCL) to distinguish them from immature T-cell neoplasms.1 Nodal forms are the most common and include well-characterised histotypes, such as angioimmunoblastic T-cell lymphoma (AITL) and anaplastic large T-cell lymphoma (ALCL, ALK + or ALK−).