Sarcomatoid Renal Cell Carcinoma

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)