title: Sarcomatoid squamous cell carcinoma of the vulva expressing smooth muscle actin and S100 protein.
abstract: BACKGROUND
  Vulvar sarcomatoid squamous cell carcinoma has been rarely reported.
  
  
  METHODS
  Case report and immunohistochemistry.
  
  
  RESULTS
  The author herein reports a peculiar vulvar tumor. An 87-year-old woman with hypertension presented with a vulvar tumor, and admitted to our hospital. Gross examination showed an elevated tumor measuring 3 × 4 × 5 cm in the vulva near the urethra. An excisional biopsy was taken, and it showed proliferation and invasion of malignant spindle cells (70% in area) and malignant polygonal cells (30% in area). There were gradual transitions between vulvar squamous epithelium and these malignant tumor cells. Immunohistochemically, the malignant sarcomatoid cells (spindle and polygonal cells) were positive for cytokeratins, epithelial membrane antigen, vimentin, α-smooth muscle actin, S100 protein, and p53 protein. They were negative for melanosome, CD34, CD68, myoglobin, and CD45. Ki-67 labeling was 63%. A pathological diagnosis of sarcomatoid squamous cell carcinoma expressing smooth muscle antigen and S100 protein was made. The patient developed lung metastasis 2 months later, and suddenly died of unknown cause.
  
  
  CONCLUSIONS
  A rare case of vulvar sarcomatoid squamous cell carcinoma expressing S100 protein and α-smooth muscle actin is reported.
authors.affiliation: Department of Pathology, Shizuoka City Shimizu Hospital, Miyakami 1231 Shimizu-Ku, Shizuoka 424-8636, Japan. piyo0111jp@yahoo.co.jp
authors.forename: Tadashi
authors.initials: T
authors.lastname: Terada
mesh_terms: D000199:Actins / Q000378:metabolism*; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D009418:S100 Proteins / Q000378:metabolism*; D012509:Sarcoma / Q000378:metabolism; D014844:Vulva / Q000473:pathology; D014846:Vulvar Neoplasms / Q000378:metabolism* / Q000473:pathology
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D009418:S100 Proteins