Limb Amputation for Tumor

Limb amputations for tumor are occasionally performed when an extremity sarcoma involves both bone and soft tissue, and a local resection is not possible. These may consist of disarticulations (eg, at shoulder or hip joint) or amputations (eg, through femur or humerus bone).

ALWAYS review your grossing plan with an attending, and photograph liberally!

Triage

  1. Take gross photos of the intact leg, being sure to include resection margin, any surface lesions, and/or any prior amputation sites.
  2. Measure leg in 3D, including:
    • Length of leg from resection margin to heel
    • Length of foot from heel to first digit
    • Length of exposed femur
    • Upper leg circumference
    • Lower leg/calf circumference
  3. Describe the skin, noting any lesions, biopsy sites, or indurations.
  4. Describe any previous amputation.
  5. Submit the nerve and vascular margins from the fresh specimen, en face.
  6. Scoop out the proximal marrow and submit marrow margin from the fresh specimen. (Does not apply to disarticulations)
  7. Ink the remaining soft tissue margin black.
  8. If clinical or radiographic concern exists for joint involvement by sarcoma, you can disarticulate the limb at the relevant joint (eg, cut through the skin, soft tissue, and synovium in order to enter the knee joint or elbow joint, and separate upper from lower limb).
    • Inspect the joint surfaces (articular cartilage, synovium, etc) for tumor seeding.
    • Subsequently, you can gross the upper and lower limbs separately, depending on the location of the tumor.
  9. If the specimen needs to be frozen before sectioning (see below), cut into the tumor and submit 2 sections of viable tumor BEFORE freezing.

Assuming that the sarcoma involves both bony and soft tissues (check imaging), our recommendation is to freeze the limb (or relevant portion of limb) in liquid nitrogen (until hard) or in deep freezer (until hard or overnight) and cut transversely with band saw, in order to preserve relevant anatomic relationships. This must be done before fixation.

  1. DO NOT EVER use the band saw alone. Make sure that a trained individual is present (PA, attending).
  2. Take the following items in a locked, covered cart to the band saw:
    1. A dewar filled with liquid nitrogen (LN2)
    2. A black rubber bucket
    3. The specimen
    4. Key to cart
  3. On a table or flat surface near the band saw, prepare an area for slices to be placed, in order, when cut. Eg, lay out blue chucks or cloths.
  4. Prepare your instruments: extra long forceps and tongs.
  5. Put on proper PPE (coat, gloves, face mask).
  6. Take the gray specimen guide from underneath the saw and attach it to the saw (slides onto the vertical slot that is on the moving component of the saw).
  7. Using the knob on the front of the saw, adjust the thickness of the cut so that once you freeze the specimen, you can begin taking cuts immediately.
  8. Once you are ready to freeze and cut specimen, note that the cuts should be made sequentially with relative rapidity such that the specimen does not thaw in the process of cutting.
  9. Pour LN2 into the black rubber bucket to just below the top black line.
  10. Dip a portion of the limb into LN2 for approximately 45-60 seconds.
  11. Cut the limb transversely:
    • If including joint, the first section near joint may need to be cut thicker than the remaining sections.
    • Then take sequential transverse sections in 0.5-1.0 cm increments (depending on your comfort with the saw).
    • Regarding the proximal most section: You may want to cut a donut of cortical bone margin to submit en face. You may also want to leave the proximal-most section with soft tissue margin thicker and then take sections perpendicular to the margin (see below).
    • Lay out all the slices on the blue chucks/clothes in order to keep orientation (see below).

 

Proximal Margin, Perpendicular

 

Cross Section, Representative

 

  1. Take gross photos the cross sections of the specimen while fresh (see above).
  2. While the specimen is still fresh, measure and document:
    • Size of the mass
    • % gross necrosis
    • Involvement of adjacent vessel(s) and nerve
    • Involvement of bone(s), including cortex, marrow, and location (diaphysis/metaphysis/epiphysis)
    • Involvement of joint space
    • Distance to skin, proximal soft tissue margin, and marrow margin(s)
  3. Determine with your attending the extent of tissue to be sampled / decalcified.
  4. Always submit NON-decalcified tumor (and/or EDTA-decalcified tumor) to preserve nucleic acids for molecular testing.
  5. Overall sections include:
    • Nerve and vascular margins previously taken, en face
    • Marrow margin previously taken
    • Cortical bone donut, en face
    • Skin and adjacent soft tissue margins, preferentially perpendicular
    • Representative mass (discuss with attending the extent of submission)
    • Representative mass with adjacent structures
      • Artery
      • Nerve
      • Bone
      • Skeletal muscle
      • Adipose tissue
    • Representative pathologic fracture, if applicable
    • Representative skip lesions in other bone(s), soft tissue(s), if applicable
    • Any other incidental findings
  6. Be sure to state “after EDTA decalcification” or “after HCl decalcification” in your cassette summary and add a Decal stain (appears as “Decalcification process” NOT “H&E Decalcification”) in Beaker. One “stain” per container will suffice, as the only result of ordering the “stain” is to drop a billing charge.

Updated 7/7/23 SRR

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