title: Composite chromophobe renal cell carcinoma with sarcomatoid differentiation containing osteosarcoma, chondrosarcoma, squamous metaplasia and associated collecting duct carcinoma: a case report.
abstract: BACKGROUND
  Chromophobe renal cell carcinoma (ChRCC) is a morphologically distinct renal cell carcinoma type which may rarely show composite morphology.
  
  
  METHODS
  A 61-year-old man presented with a composite ChRCC with sarcomatoid transformation containing osteosarcomatous, chondrosarcomatous and squamous metaplastic differentiation and associated with a high-grade collecting duct carcinoma (CDC). The patient presented with a metastatic disease in the regional lymph nodes, comprised only of CDC, and died after 21 months.
  
  
  CONCLUSIONS
  Although ChRCC associated with sarcomatoid change has been well documented, the presence of osteosarcoma has been previously reported in only 5 ChRCCs, 2 of which also contained chondrosarcoma. Squamous differentiation has been previously found in only 2 ChRCCs with sarcomatoid change, and ChRCC associated with CDC has been previously reported in only 3 cases, but none with heterologous elements. To our knowledge this represents a previously unreported composite type of RCC, with an aggressive clinical behavior.
authors.forename: Arjumand
authors.initials: A
authors.lastname: Husain
authors.forename: Bernhard J
authors.initials: BJ
authors.lastname: Eigl
authors.forename: Kiril
authors.initials: K
authors.lastname: Trpkov
mesh_terms: D002292:Carcinoma, Renal Cell / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D002813:Chondrosarcoma / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012516:Osteosarcoma / Q000175:diagnosis* / Q000473:pathology