Kidney Tumors

Auto text: “Insert Pediatric Nephrectomy”

Pediatric renal tumors are often resected without histologic confirmation of the diagnosis.  Considerations include: Wilms Tumor, Congenital Mesoblastic Nephroma, Clear Cell Sarcoma or Rhabdoid Tumor.  Specimens may come as radical or partial nephrectomies.  Please consult the case attending if any questions arise on the triage / gross methods for these specimens.


  1. Photograph the external surfaces of the specimen prior to inking or sectioning. This practice allows for proper documentation of margins and capsular violation.
  2. DO NOT strip the capsule from the specimen.
  3. Weigh and measure specimen in 3 dimensions.
  4. Measure length and diameter of attached ureter and vessels.
  5. Examine the renal vein for tumor thrombus. If present, note if it is adherent to the intima or not.  Renal vein margin is considered positive ONLY if tumor thrombus has been transected, not if it has a smooth surface that bulges to the end of the vein.
  6. Take margins:
    • Distal ureter margin, en face.
    • Medial sinus margin, en face (the medial end of the soft tissues surrounding the renal artery and vein):  If the soft tissue ends where the vessels end, take soft tissue and vessels together.  If the vessels continue past the soft tissue, take the distal-most vessels in one cassette, and the distal-most soft tissue (with vessels) in a separate cassette.
    • Save these margins in cassettes within container.
  7. Ink the outer surface adjacent to tumor.
  8. Bisect kidney through renal hilus and surrounding perinephric fat.
  9. Identify and measure adrenal, if present.
  10. Identify and measure kidney, including cortical thickness.
  11. Identify and measure tumor (3 dimensions) and distance to the following margins: external (Gerota’s fascia or fat), renal vasculature, ureter.
  12. Photograph cut surface of kidney with tumor.
  13. Snap freeze tumor (1 gram total) and non-neoplastic kidney. Ensure tissue from each mass is frozen.
  14. Fix in formalin.


  1. Examine and describe:
    • invasion of tumor into perinephric or renal sinus adipose tissue
    • invasion of tumor into renal vein, calyces, pelvis, ureter
    • extension of tumor to inked surface
    • non-neoplastic kidney parenchyma and cortical thickness
  2. Submit representative sections of tumor (1 per cm), making sure to document on a gross photograph or diagram exactly WHERE the sections are taken from (see image).  This practice allows for proper estimation of focal or diffuse anaplasia (if present).
  3. Please thoroughly sample the interface of tumor and normal, as well as the renal sinus and hilar fat/vessels.
  4. For multicentric tumors (usually Wilms), sample each nodule.
  5. Sample potential nephrogenic rests in uninvolved kidney: Nephrogenic rests often appear paler than the normal kidney parenchyma.  Take 2-3 sections of normal kidney to assess for nephrogenic rests.
  6. In summary, your sections should be as follows:
    • Ureteral, medial sinus and vascular margins (saved from triage).
    • Tumor (1 per cm) including grossly-different areas and tumor with adjacent renal parenchyma / renal sinus.
    • Deepest penetration of tumor into perinephric or renal sinus adipose tissue.
    • Deepest penetration into renal vein.
    • Tumor closest to the inked soft tissue margin (Gerota’s fascia).
    • Multiple sections of uninvolved kidney.
    • Any identified lymph nodes within hilar and peripheral fat.
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