Stanford School of Medicine

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)

Bibliography (for Staging)

  • 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
  • Delahunt B. Advances and controversies in grading and staging of renal cell carcinoma. Mod Pathol. 2009 Jun;22 Suppl 2:S24-36.
  • Bonsib SM. The renal sinus is the principal invasive pathway: a prospective study of 100 renal cell carcinomas. Am J Surg Pathol. 2004 Dec;28(12):1594-600.
  • Bonsib SM. Renal veins and venous extension in clear cell renal cell carcinoma. Mod Pathol. 2007 Jan;20(1):44-53.
  • Bonsib SM. T2 clear cell renal cell carcinoma is a rare entity: a study of 120 clear cell renal cell carcinomas. J Urol. 2005 Oct;174(4 Pt 1):1199-202; discussion 1202.
  • Herrmann E, Trojan L, Becker F, Wülfing C, Schrader AJ, Barth P, Stöckle M, Hammerschmied CG, Staehler M, Stief C, Haferkamp A, Hohenfellner M, Legal W, Wullich B, Bolenz C, Klein T, Noldus J, Bierer S, Hertle L, Brenner W, Roos F, Michel MS, Walter B, Wieland W, Gerss J, Otto W, Hartmann A. Prognostic factors of papillary renal cell carcinoma: results from a multi-institutional series after pathological review. J Urol. 2010 Feb;183(2):460-6.
  • Trpkov K, Grignon DJ, Bonsib SM, Amin MB, Billis A, Lopez-Beltran A, Samaratunga H, Tamboli P, Delahunt B, Egevad L, Montironi R, Srigley JR; members of the ISUP Renal Tumor Panel. Handling and staging of renal cell carcinoma: the International Society of Urological Pathology Consensus (ISUP) conference recommendations. Am J Surg Pathol. 2013 Oct;37(10):1505-17.


  • 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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