title: A light microscopic and immunohistochemical evaluation of scars.
abstract: BACKGROUND
  Scars are commonly encountered by dermatopathologists and usually do not present a diagnostic challenge. However, in some cases, the pathologist may need to consider a broad differential diagnosis including fibrohistiocytic tumors, smooth muscle tumors, myofibroblastic proliferations and desmoplastic malignant melanoma. Although specific histologic aspects of scars have been well studied, a complete histochemical profile of scars, especially at various stages of evolution, has not been described.
  
  
  METHODS
  Twenty-five cases of scars including 8 normal scars, 5 hypertrophic scars and 12 keloids were studied. Sections were examined with Verhoeff van Giesson, colloidal iron, Giemsa, smooth muscle actin (SMA), CD34, Factor XIIIa and S-100.
  
  
  RESULTS
  All scars were negative for CD34 expression. Factor XIIIa immunostaining identified only rare dermal dendrocytes. S-100 was absent in 23 of 25 cases and stained scattered cells (less than 10%) in the other 2 cases. SMA was positive in 14 of 25 cases with 6 of these showing staining of up to 50% of spindled cells. Elastic fibers were markedly reduced or absent in all cases, mucin showed moderate or marked staining in three-fourths of the cases and dermal mast cells showed a moderate increase in 5 cases.
  
  
  CONCLUSIONS
  These findings confirm prior reports that negative staining with CD34, Factor XIIIa and S-100 can help differentiate scars from dermatofibrosarcoma protuberans, dermatofibroma and desmoplastic malignant melanoma, respectively. SMA staining is much more variable and requires careful interpretation.
authors.affiliation: Department of Dermatology, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, Ohio, USA.
authors.forename: Nandan V
authors.initials: NV
authors.lastname: Kamath
authors.forename: Adrian
authors.initials: A
authors.lastname: Ormsby
authors.forename: Wilma F
authors.initials: WF
authors.lastname: Bergfeld
authors.forename: Nancy S
authors.initials: NS
authors.lastname: House
mesh_terms: D000199:Actins / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D002921:Cicatrix / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D004549:Elastin / Q000378:metabolism; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D007124:Immunoenzyme Techniques; D007627:Keloid / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D008297:Male; D008407:Mast Cells / Q000473:pathology; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism
chemical_list: D000199:Actins; D015415:Biomarkers; D009077:Mucins; D004549:Elastin