Anaplastic large cell lymphoma (ALCL) is a rare and aggressive peripheral T-cell non-Hodgkin lymphoma, belonging to the group of CD30-positive lymphoproliferative disorders, which affects lymph nodes and extranodal sites. It is comprised of two sub-types, based on the expression of a protein called anaplastic lymphoma kinase (ALK): ALK positive and ALK negative ALCL (see these terms).