title: Anaplastic Large Cell Lymphoma.
abstract: Session 8 of the 2005 Society of Hematopathology/European Association for Haematopathology Workshop was devoted to anaplastic large cell lymphoma (ALCL). Most cases submitted were anaplastic lymphoma kinase (ALK)+ ALCL highlighting unusual clinical settings, histologic variants, and variant translocation partners. Cases submitted as ALK- ALCL emphasized the immunohistochemical overlap with classical Hodgkin lymphoma (eg, CD15+/CD30+). It was also clear that consensus histologic and immunohistochemical criteria for the diagnosis of ALK-ALCL are lacking. Many expressed the opinion that ALK-ALCL is not a distinct entity at the immunophenotypic or genetic level and is better designated as peripheral T-cell lymphoma (PTCL), unspecified. Others suggested that the histologic features of ALK-ALCL are distinctive nevertheless and that this diagnosis has meaning that is lost by designating these neoplasms as PTCL, unspecified. This session also included CD30+ anaplastic lymphomas involving skin in which the differential diagnosis included cutaneous ALCL and systemic ALK-ALCL.
authors.affiliation: Department of Hematopathology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030-4095, USA.
authors.forename: L Jeffrey
authors.initials: LJ
authors.lastname: Medeiros
authors.forename: Kojo S J
authors.initials: KS
authors.lastname: Elenitoba-Johnson
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D017730:Ki-1 Antigen / Q000032:analysis; D016403:Lymphoma, Large B-Cell, Diffuse / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D011505:Protein-Tyrosine Kinases / Q000032:analysis*; D020794:Receptor Protein-Tyrosine Kinases; D012878:Skin Neoplasms / Q000473:pathology
chemical_list: D017730:Ki-1 Antigen; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases