Sarcomatoid differentiation may be seen in many types of renal carcinomas
(de Peralta-Venturina; Cheville)
It no longer refers to a type of carcinoma
It is considered an adverse prognostic factor
Prognosis may be worse than simple grade 4 carcinoma
Defined as a spindle cell component measuring at least one low power (40x) field with either
Adjacent carcinoma, or
Evidence of epithelial differentiation in the spindle cells
Spindle cells usually show moderate to marked atypia
Frequent patterns include fibrosarcoma, malignant fibrous histiocytoma, rhabdomyosarcoma
Occasional cases have low grade atypia in spindle component
No clinical significance to type of differentation or degree of atypia
May arise in setting of many types of carcinoma
Clear cell RCC (reported 5-8% incidence of sarcomatoid foci, in our experience it is less frequent)
Papillary RCC (2-3% incidence)
Chromophobe RCC (9% incidence)
Collecting duct carcinoma (39% incidence)
Bibliography (for Grading)
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.
Delahunt B, Sika-Paotonu D, Bethwaite PB, William Jordan T, Magi-Galluzzi C, Zhou M, Samaratunga H, Srigley JR. Grading of clear cell renal cell carcinoma should be based on nucleolar prominence. Am J Surg Pathol. 2011 Aug;35(8):1134-9.
Delahunt B, Bethwaite PB, Nacey JN. Outcome prediction for renal cell carcinoma: evaluation of prognostic factors for tumours divided according to histological subtype. Pathology. 2007 Oct;39(5):459-65.
Lohse CM, Blute ML, Zincke H, Weaver AL, Cheville JC. Comparison of standardized and nonstandardized nuclear grade of renal cell carcinoma to predict outcome among 2,042 patients. Am J Clin Pathol. 2002 Dec;118(6):877-86.
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.
Cheville JC, Lohse CM, Zincke H, Weaver AL, Leibovich BC, Frank I, Blute ML. Sarcomatoid renal cell carcinoma: an examination of underlying histologic subtype and an analysis of associations with patient outcome. Am J Surg Pathol. 2004 Apr;28(4):435-41.
Sika-Paotonu D, Bethwaite PB, McCredie MR, William Jordan T, Delahunt B. Nucleolar grade but not Fuhrman grade is applicable to papillary renal cell carcinoma. Am J Surg Pathol. 2006 Sep;30(9):1091-6.
Delahunt B, Sika-Paotonu D, Bethwaite PB, McCredie MR, Martignoni G, Eble JN, Jordan TW. Fuhrman grading is not appropriate for chromophobe renal cell carcinoma. Am J Surg Pathol. 2007 Jun;31(6):957-60..
Paner GP, Amin MB, Alvarado-Cabrero I, Young AN, Stricker HJ, Moch H, Lyles RH. A novel tumor grading scheme for chromophobe renal cell carcinoma: prognostic utility and comparison with Fuhrman nuclear grade. Am J Surg Pathol. 2010 Sep;34(9):1233-40.
Fuhrman SA, Lasky LC, Limas C. Prognostic significance of morphologic parameters in renal cell carcinoma. Am J Surg Pathol. 1982 Oct;6(7):655-63.
Staging
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)
Critical/controversial points in staging of RCC include:
pT3a is defined as extension into perirenal fat
This requires actual 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.
