title: Diagnostic value of CD163 in cutaneous spindle cell lesions.
abstract: BACKGROUND
  The histologic diagnosis of atypical fibroxanthoma (AFX) can sometimes be challenging. No specific marker exists to confirm the diagnosis other than excluding other entities. CD163 has been shown to have great specificity for tumors of monocyte/histiocyte lineage. In this study, we evaluated the diagnostic utility of CD163 in diagnosing AFX and in identifying skin lesions with histiocytic/dendritic derivation.
  
  
  METHODS
  A total of 157 cases, including 14 AFXs, 5 spindle cell squamous cell carcinomas (SCCs), and 7 spindle cell/desmoplastic melanomas, along with other cutaneous spindle cell and histiocytic/fibrohistiocytic lesions, were stained with CD163.
  
  
  RESULTS
  CD163 was expressed in 11 of 14 (79%) AFXs, with moderate to strong intensity. No staining was observed in cases of spindle cell SCC (0/5) and dermatofibrosarcoma protuberans (0/10). Rare spindle cell/desmoplastic melanomas (2/7) and cutaneous leiomyosarcomas (1/5) demonstrated positive staining. CD163 reactivity was seen in 24 of 29 of benign fibrous histiocytomas (BFHs), including 8 of 8 cellular fibrous histiocytomas and 6 of 9 epithelioid cell histiocytomas. The majority of cutaneous histiocytic lesions, including juvenile xanthogranuloma, Langerhans cell histiocytosis and Rosai-Dorfman disease, were positive for CD163.
  
  
  CONCLUSIONS
  CD163 is a useful adjunct in distinguishing AFX from other malignant cutaneous spindle cell tumors and offers improved specificity in identifying cutaneous histiocytic/dendritic lesions.
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI 48109-0602, USA.
authors.forename: Pedram
authors.initials: P
authors.lastname: Pouryazdanparast
authors.forename: Limin
authors.initials: L
authors.lastname: Yu
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Cutlan
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Olsen
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Fullen
authors.forename: Linglei
authors.initials: L
authors.lastname: Ma
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis*; D015214:Antigens, Differentiation, Myelomonocytic / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005354:Fibrosarcoma / Q000378:metabolism* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D000098902:CD163 Antigen
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D014408:Biomarkers, Tumor; D000098902:CD163 Antigen; D011956:Receptors, Cell Surface