Bone Tumor

Auto Text: “Insert Bone Tumor”

Remember: For any tumor adjacent to / involving bone, if any part of the tumor is SOFT and does not NEED decalcification, please isolate 1-2 sections and submit as non-decalcified tumor (important for possible molecular testing). If this is not possible, isolate at least 2 thin sections and decalcify in EDTA after fixation. Then proceed with decal as necessary for the remainder of the case.

Triage

  1. Bone resections are performed for both benign and malignant lesions.
  2. Often there will be an intra-operative consultation.  You should review the results of the frozen section or prior biopsy along with the patient’s history and radiologic findings.
  3. Always contact an attending to review anatomy and plan your dissection.
  4. Determine the type of resection (skin/soft-tissue sparing, amputation, disarticulation). Remember, take gross photographs – intact and after sectioning.
  5. Many resections will consist of a long bone with attached soft tissue, skeletal muscle, and skin. To triage these:
    • Orient the specimen (proximal and distal / anterior and posterior / medial and lateral).
    • Measure in 3-dimensions, including the size of the attached soft tissue/muscle and skin.
    • Ink the soft tissue margins black.
    • There are different options for sectioning. Discuss each case with an attending.
      • If the specimen is fresh (not yet fixed) you can consider freezing the entire intact specimen in liquid nitrogen and cutting bone and soft tissue together on the band saw. In this case, you do NOT have to separate soft tissue from bone.
      • Alternatively, you will have to deal with the soft tissue separately from the bone: Serially section the soft tissue perpendicular to the long axis and search for soft tissue tumor nodules. Submit representative soft tissue margins (including closest) from anterior, posterior, medial and lateral. In order to cut the bone, you will have to remove all soft tissues.
    • Whether you are dealing with a fresh frozen specimen or a fixed long bone, you will need to cut into it with the band saw. Start with a full face longitudinal section through the center of bone. Using the band saw in the morgue, cut a longitudinal section about 0.3-0.4 cm in thickness and fix it in formalin overnight. The section you select should display the greatest extent of tumor and encompass any cortical defects.
    • You should also use the band saw to make additional cuts in the remaining bone perpendicular to your full-face section. For example, if your full-face section is taken in the coronal plane, cut the amputated anterior and posterior bone pieces in the sagittal plane to evaluate for tumor.
    • *Ask for supervision while using the band saw. DO NOT use alone.*
    • Try to brush off / wash off bone dust as it may interfere with visualizing the tissue.
    • Photograph your cut section.
    • Remember to preserve at least 2 blocks for molecular testing. Either identify soft tumor that does NOT need decalcification. Or isolate sections for fixation and decalcification in gentle EDTA.
    • Following complete fixation, submerge the full-face bone section in decal (8 – 48 hours, depending on thickness and extent of disease).
    • Monitor your specimen frequently – Overdecalcification is detrimental to histologic quality.  The specimen is “done” when it can be bent easily and a pin penetrates the cortical bone.
    • After decal, rinse the section in water before submission.  This helps prevent continued degradation.
  6. Some resections will be complete amputations (AKAs, BKAs, or forequarter). To triage these:
    • Measure the specimen in 3-dimensions.
    • Identify the resection margin. Mark or remove any skin, soft tissue, vascular, or nerve margins that may get lost upon sectioning.
    • If previous histologic material documents the diagnosis, the limb may be submerged in liquid nitrogen and cut transversely on the band saw. Ask an attending before performing these techniques!
    • Disarticulation through the knee joint may aid in sectioning transversely.
    • Check with your attending for specifics of grossing complex amputations.

Gross

  1. For full face longitudinal sections, check if decalcification is complete. The section of bone should be flexible.
  2. Make sure you document size of tumor, involvement of marrow/cortex/soft tissue, involvement of diaphysis/metaphysis/epiphysis, distance to marrow margins and peripheral margins.
  3. For full face longitudinal sections, submit the entire thin section, mapping out your sections on the MacroPath software.  Also submit additional representative tumor from the adjacent bone.
  4. Sections should include:
    • Marrow margin (if not already taken on frozen section).
    • Skin, soft tissue, skeletal muscle, vascular, or neural margins.
    • Entire face of bone with accompanying diagram.
    • Additional representative tumor.
    • Additional pertinent documentation – including tumor extensions into soft tissue/nerve/skeletal muscle.
  5. Documenting and charging for decalcification process:
    • Be sure to state “after [HCl or EDTA] decalcification” in your cassette summary for each cassette you decal, stating the TYPE of solution you used for each cassette.
    • Add a Decal stain (appears as “Decalcification process” NOT “H&E Decalcificaton”) in CoPath. One “stain” per container will suffice, as the only result of ordering the “stain” is to drop a billing charge.
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