title: Atypical fibroxanthoma with prominent sclerosis.
abstract: BACKGROUND
  Malignant cutaneous spindle cell lesions with marked sclerosis are uncommon. Only a few cases of cutaneous leiomyosarcoma and dermatofibrosarcoma protuberans with sclerosis have been published.
  
  
  METHODS
  We report a case of atypical fibroxanthoma (AFX) with prominent sclerosis and hyalinization occurring on the scalp of an 81-year-old male.
  
  
  RESULTS
  Histopathologic examination revealed an exophytic, well-delineated, focally ulcerated tumor arising in sun-damaged skin. The lesion was composed of atypical spindle cells arranged in a fascicled and vaguely storiform pattern. Occasional multinucleated giant cells were present. The tumor cells were strongly positive for CD99 (O13), vimentin, and smooth muscle actin, and focally positive for CD68. There was striking sclerosis with hyalinization throughout the lesion.
  
  
  CONCLUSIONS
  Rarely, AFX may exhibit marked sclerosis with areas of complete replacement of tumor by hyalinized collagen. In a small biopsy, such hyalinization may be a diagnostic pitfall leading to an erroneous diagnosis.
authors.affiliation: Calgary Laboratory Services, University of Calgary, Calgary, AB, Canada. andrea.bruecks@cls.ab.ca
authors.forename: Andrea K
authors.initials: AK
authors.lastname: Bruecks
authors.forename: Shaun A
authors.initials: SA
authors.lastname: Medlicott
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Trotter
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006258:Head and Neck Neoplasms / Q000737:chemistry / Q000150:complications / Q000473:pathology*; D018219:Histiocytoma, Benign Fibrous / Q000737:chemistry / Q000150:complications / Q000473:pathology*; D006801:Humans; D006818:Hyalin / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000473:pathology; D012535:Scalp; D012598:Sclerosis / Q000150:complications / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000737:chemistry / Q000150:complications / Q000473:pathology*; D013472:Sunlight / Q000009:adverse effects