title: CD30+ lymphoproliferative disorders: histopathology, differential diagnosis, new variants, and simulators.
abstract: CD30+ lymphoproliferative disorders of the skin (CD30+ LPD) represent a well-defined spectrum of primary cutaneous T-cell lymphomas which have been recognized as distinct entities in recent lymphoma classifications. Lymphomatoid papulosis and anaplastic large-cell lymphoma share the expression of CD30 antigen as a common phenotypic hallmark but differ in regard to their clinical and histologic features as well as their biologic behavior. This article summarizes the histologic features of CD30+ LPD and presents recently identified new clinicopathologic variants of CD30+ LPD. There is an increasing number of reactive inflammatory disorders and neoplastic diseases which are composed of or contain a significant number of CD30+ cells and mimic LyP or anaplastic large cell lymphoma clinically or histologically. Differential diagnostic considerations focus on other lymphoproliferative processes with CD30+ tumor cells as well as non-lymphoid neoplasms and inflammatory simulators. The term CD30+ pseudolymphoma is proposed to designate inflammatory processes with CD30+ T cells. The final diagnosis of CD30+ LPD is based on a synthesis of clinical, histologic, phenotypic, and molecular genetic findings.
authors.affiliation: Department of Dermatology, University Hospital Zürich, Switzerland. kempf@derm.unizh.ch
authors.forename: Werner
authors.initials: W
authors.lastname: Kempf
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D006801:Humans; D017730:Ki-1 Antigen / Q000378:metabolism*; D016410:Lymphoma, T-Cell, Cutaneous / Q000175:diagnosis; D008232:Lymphoproliferative Disorders / Q000175:diagnosis* / Q000378:metabolism; D012867:Skin / Q000473:pathology*; D012871:Skin Diseases / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D017730:Ki-1 Antigen