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Surgical Pathology Criteria

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Sarcomatoid Renal Cell Carcinoma


  • Renal cell carcinoma of any type exhibiting at least focal sarcomatoid/spindle cell differentiation

Alternate/Historical Names

  • Carcinosarcoma
  • Spindled carcinoma

Diagnostic Criteria

  • Represents a form of high grade transformation, not a distinct subtype of renal cell carcinoma
    • May occur in any of the standard subtypes of renal cell carcinoma
    • Reported to occur in 5-8% of renal cell carcinomas
      • Less common in our experience
    • Should not be reported as the subtype of renal cell carcinoma
  • Requires evidence of epithelial differentiation
    • Concurrent areas of renal cell carcinoma of any type, OR
    • Immunohistochemical positivity for keratin or EMA
      • (Keratin and EMA expression may be appropriate for some sarcomas, including leiomyosarcomas)
  • Requires a spindle cell component measuring at least one low power (40x) field
    • May be discrete or intermixed with epithelial elements
    • May be very focal
  • Most common patterns are fibrosarcoma and malignant fibrous histiocytoma
    • Rare cases reported with patterns of rhabdomyosarcoma, chondrosarcoma, osteosarcoma and hemangiopericytoma
    • Pattern does not appear to affect prognosis
  • Grade of sarcoma is not clinically significant
    • May range from low to high
      • Based on cellularity, atypia, mitotic figures
  • See Classification/Lists in menu at left for links to specific carcinoma subtypes

John P Higgins MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting:: January 24, 2011

Supplemental studies


Phenotype of sarcomatoid component
Broad spectrum anti-keratin 95-100%
EMA 50-100%
High MW keratin 0-20%*
Vimentin 33-100%
Actin 33%
Desmin neg
*Few studies, but HMW keratin only reported in collecting duct carcinomas

Differential Diagnosis

Primary renal sarcomas

  • Must not have associated epithelial components
  • Keratin and EMA should be negative unless appropriate for type of sarcoma
  • Specific sarcoma type markers such as desmin for leiomyosarcoma may be useful

Sarcomatoid urothelial carcinoma

  • Identification of location and type of associated carcinoma are important
  • History of prior urothelial tract carcinoma is helpful
  • High molecular weight keratin and p63 staining would support urothelial carcinoma although published evidence is scant


  • Generally only a problem if smooth muscle component predominates
  • Smooth muscle differentiation is unusual in sarcomatoid RCC
  • HMB45 staining would not be expected in sarcomatoid RCC (but no published evidence)
  • Identification of associated typical angiomyolipoma or RCC is important

Grading / Staging


  • Presence of sarcomatoid differentiation indicates high grade
    • Grade of sarcoma is not relevant


  • Use TNM staging for all renal carcinomas at present
    • Remember that it is based predominantly on clear cell carcinomas
    • It has not been validated as applicable to other types of carcinoma (see Herrmann for an example)
      • Note that oncocytomas can infiltrate fat and exhibit vascular invasion without affecting prognosis (Perez-Odonez)
  • Critical/controversial points in staging of RCC include:
    • pT3a is defined as extension into perirenal fat
      • This requires actual touching of fat, preferably infiltration into and between fat cells
        • It does not include bulging tumor with stretched, thin capsule that appears to touch fat
      • Classically has been considered fat peripheral to the cortical capsule
        • It appears that renal sinus (peripelvic) fat should be considered equivalent
          • The renal sinus must be examined grossly and appropriately sampled
    • pT3 requires gross involvement of renal vein and or vena cava
      • This requires an adequate gross examination
      • Retraction of vascular wall around a lumenal tumor thrombus may falsely suggest a positive margin
        • Positive vascular margin requires involvement of the vessel wall at the margin
    • Direct (contiguous) invasion of the adrenal gland (pT4) should be distinguished from discontiguous (metastatic) involvement (pM1)


  • Wide age range 29-81 years
  • Poor prognosis
    • 22% 5 year survival
  • Clinically significant features
    • Percentage of sarcomatoid pattern (>50%)
    • Vascular invasion
    • Degree of necrosis
    • High TNM stage
  • Type and grade of sarcoma and type of carcinoma is not clinically significant

Classification / Lists

Renal epithelial neoplasms


  • Murphy WM, Grignon DJ, Perlman EJ. Tumors of the Kidney, Bladder and Related Urinary Structures, Atlas of Tumor Pathology, AFIP Fourth Series, Fascicle 1, 2004
  • Eble JN, Sauter G, Epstein JI, Sesterhenn IA eds. World Health Organization Classification of Tumors. Pathology and genetics of tumors of the Urinary System and Male Genital Organs. IARC Press: Lyon 2004.
  • de Peralta-Venturina M, Moch H, Amin M, Tamboli P, Hailemariam S, Mihatsch M, Javidan J, Stricker H, Ro JY, Amin MB. Sarcomatoid differentiation in renal cell carcinoma: a study of 101 cases. Am J Surg Pathol. 2001 Mar;25(3):275-84.
  • Delahunt B. Sarcomatoid renal carcinoma: the final common dedifferentiation pathway of renal epithelial malignancies. Pathology. 1999 Aug;31(3):185-90.
  • Auger M, Katz RL, Sella A, Ordóñez NG, Lawrence DD, Ro JY. Fine-needle aspiration cytology of sarcomatoid renal cell carcinoma: a morphologic and immunocytochemical study of 15 cases. Diagn Cytopathol. 1993;9(1):46 51.
  • Baer SC, Ro JY, Ordonez NG, Maiese RL, Loose JH, Grignon DG, Ayala AG. Sarcomatoid collecting duct carcinoma: a clinicopathologic and immunohistochemical study of five cases. Hum Pathol. 1993 Sep;24(9):1017-22.
  • DeLong W, Grignon DJ, Eberwein P, Shum DT, Wyatt JK. Sarcomatoid renal cell carcinoma. An immunohistochemical study of 18 cases. Arch Pathol Lab Med. 1993 Jun;117(6):636-40.
  • Quiroga-Garza G, Khurana H, Shen S, Ayala AG, Ro JY. Sarcomatoid chromophobe renal cell carcinoma with heterologous sarcomatoid elements. A case report and review of the literature. Arch Pathol Lab Med. 2009 Nov;133(11):1857-60.
  • Gira FA, Barbieri A, Fellegara G, Zompatori M, Corradi D. Dedifferentiated chromophobe renal cell carcinoma with massive osteosarcoma-like divergent differentiation: a singular entity in the spectrum of retroperitoneal calcifying tumors. Int J Surg Pathol. 2010 Oct;18(5):419-23.
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