title: Diagnosis of mycosis fungoides: a comparative immunohistochemical study of T-cell markers using a novel anti-CD7 antibody.
abstract: Mycosis fungoides (MF) is the most common form of primary cutaneous T-cell lymphoma. In its early stage it may mimic benign dermatoses both on a clinical and histologic basis. MF usually expresses CD3 and CD4 (T-cell) markers. CD7 is expressed on about 90% of CD4 T cells and is often deficient on malignant T cells. Thus, CD7 may be useful in evaluating the nature of dermal lymphoid infiltrates. The aim of this study was to evaluate the usefulness of immunohistochemical detection of T-cell markers on paraffin-embedded sections, CD3 and CD7 (clone CBC.37), in the differential diagnosis of MF and benign dermatoses. Forty-two patients with diffuse dermal T-lymphocytic infiltrates were selected. Previous clinicopathologic correlation and follow-up had established the diagnosis of MF in 31 patients and benign dermatoses in 11. The mean value of stained cells in MF was 86.45% for CD3 and 53.09% for CD7 (P<0.001); in benign dermatoses it was 79.09% for CD3 and 73.63% for CD7 (P=0.669). CD7 immunolabeling was significantly lower in the MF group (P=0.048). A semiquantitative evaluation revealed a considerable loss of CD7 immunolabeling in comparison with CD3 in patients with MF. The authors conclude that CD7 study may represent a valuable tool in the distinction between inflammation and neoplasia in T-lymphoproliferative skin disorders.
authors.affiliation: Department of Pathology, Medical School of the State University of Campinas, Campinas, SP, Brazil.
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: Cotta
authors.forename: Maria Letícia
authors.initials: ML
authors.lastname: Cintra
authors.forename: Elemir Macedo
authors.initials: EM
authors.lastname: de Souza
authors.forename: Cristiano Aparecido
authors.initials: CA
authors.lastname: Chagas
authors.forename: Luis Alberto
authors.initials: LA
authors.lastname: Magna
authors.forename: Raul Negrão
authors.initials: RN
authors.lastname: Fleury
authors.forename: Pierre
authors.initials: P
authors.lastname: Brousset
authors.forename: José
authors.initials: J
authors.lastname: Vassallo
mesh_terms: D019011:Antigens, CD7 / Q000097:blood*; D014408:Biomarkers, Tumor / Q000032:analysis*; D003937:Diagnosis, Differential; D006801:Humans; D007120:Immunochemistry; D009182:Mycosis Fungoides / Q000175:diagnosis* / Q000378:metabolism; D016612:Paraffin Embedding; D012871:Skin Diseases / Q000175:diagnosis / Q000378:metabolism; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D013601:T-Lymphocytes / Q000473:pathology
chemical_list: D019011:Antigens, CD7; D014408:Biomarkers, Tumor