title: Immunophenotyping of dermal spindle cell tumors: diagnostic value of monocyte marker Ki-M1p and histogenetic considerations.
abstract: Various studies have reported the utility of anti-CD34 staining in the differential diagnosis of dermal spindle-cell tumors. To investigate whether monoclonal antibody Ki-M1p might add practical diagnostic information, we examined a total of 120 cutaneous spindle cell neoplasms using a panel of markers. Anti-CD34 antibody QBEnd/10 consistently stained dermatofibrosarcomas, Kaposi's sarcomas, neurofibromas, and, to a lesser extent, hemangiopericytomas. A positive reaction was also found in > 18% of the dermatofibromas. Ki-M1p staining showed an intense immunoreaction in all dermatofibromas, whereas no reactivity was observed in dermatofibrosarcomas. In addition, a subset of cells was labeled in atypical fibroxanthomas and Kaposi's sarcomas. Neurofibromas, spindle-cell hemangioendotheliomas, and hemangiopericytomas were negative. Dermatofibrosarcomas and atypical fibroxanthomas also moderately expressed smooth muscle-specific actin. Immunohistochemically, a discrimination between dermatofibrosarcomas and neurofibromas was possible only by means of an antibody against the nerve growth factor receptor. We conclude that the combination of several antibodies, in particular anti-CD34 and Ki-M1p, may improve the accuracy of diagnostic immunohistochemistry in the field of cutaneous spindle cell tumors. We speculate that dermatofibroma is primarily a macrophage-rich inflammatory lesion in which cytokine secretion induces a secondary proliferation of fibroblasts, whereas dermatofibrosarcoma is likely to issue from primitive dermal cells of uncertain origin.
authors.affiliation: Department of General Pathology, University of Kiel, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Rudolph
authors.forename: B
authors.initials: B
authors.lastname: Schubert
authors.forename: H H
authors.initials: HH
authors.lastname: Wacker
authors.forename: R
authors.initials: R
authors.lastname: Parwaresch
authors.forename: C
authors.initials: C
authors.lastname: Schubert
mesh_terms: D000911:Antibodies, Monoclonal; D018952:Antigens, CD34 / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis*; D001324:Autoantigens; D014408:Biomarkers, Tumor / Q000032:analysis*; D003593:Cytoplasm / Q000473:pathology; D018223:Dermatofibrosarcoma / Q000473:pathology; D003937:Diagnosis, Differential; D004730:Endothelium, Vascular / Q000473:pathology; D006393:Hemangiopericytoma / Q000473:pathology; D006801:Humans; D016130:Immunophenotyping; D009455:Neurofibroma / Q000473:pathology; D009687:Nuclear Proteins / Q000032:analysis*; D046988:Proteasome Endopeptidase Complex; D012514:Sarcoma, Kaposi / Q000473:pathology; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000473:pathology*
chemical_list: D000911:Antibodies, Monoclonal; D018952:Antigens, CD34; D000954:Antigens, Surface; D001324:Autoantigens; D014408:Biomarkers, Tumor; C099558:Ki antigen; D009687:Nuclear Proteins; D046988:Proteasome Endopeptidase Complex