title: Sarcomatoid collecting duct carcinoma.
abstract: BACKGROUND
  Collecting duct carcinoma has recently been recognized as a distinct entity among renal cell carcinomas and shows aggressive clinical behavior.
  
  
  METHODS
  A fatal case of collecting duct carcinoma with sarcomatoid features in an 80-year-old man is described, and the results of immunohistochemistry and flow cytometric analysis are presented.
  
  
  RESULTS
  The tumor, which was white and had infiltrating margins in the cortex and medulla, consisted of adenocarcinomatous and sarcomatous components. The adenocarcinomatous component was characterized by tubular arrangement of atypical cells with high-grade nuclear features and desmoplastic stroma. The sarcomatous component had a malignant fibrous histocytoma-like appearance. The tumor cells in the adenocarcinomatous area were positive for cytokeratin 19, Ulex europaeus agglutinin I, peanut agglutinin, and soybean agglutinin. The tumor was DNA diploid. The patient died of disease 3 months after diagnosis.
  
  
  CONCLUSIONS
  This study suggests that sarcomatoid collecting duct carcinoma may be one of the most aggressive tumors of the kidney.
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002296:Carcinosarcoma / Q000473:pathology*; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D007685:Kidney Tubules, Collecting / Q000473:pathology*; D008297:Male