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Hematopathology grossing

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IntroductionEdit

  • When specimens arrive fresh in the gross room with clinical suspicion for lymphoid malignancy, do not dunk the tissue in formalin.
  • Page the hematopathology team if this is done at your institution. They will come examine the specimen and take samples for their special studies (usually B5 fixation, flow cytometry, touch preps, or smears).
    • Or do these things yourself

Flow CytometryEdit

The heme team is responsible for taking tissue for flow cytometry. In the event that they are unavailable, the frozen resident may be asked to do it.

  • Choose representative areas of the sample adding up to a cube about 0.5 cm on a side.
  • Place this tissue on a slide or dental wax and carefully mince it into cubes no more than 0.1 cm on a side.
  • Transfer the minced tissue into 15 ml of RPMI or other medium in a blue-topped conical tube.
  • Label tube with patient name and MRN, today’s date, and nature of specimen.
  • Complete flow requisition form and send specimen for flow.

B5 fixationEdit

This is a mercury-containing fixative (unfortunately toxic) that gives excellent nuclear detail. The heme team will often fix a small piece of suspected lymphoma in B5 and fix the rest in formalin. If they are unavailable, the frozen resident may do it.

  • Take a thin slice of tissue, no more than 2 mm thick (the fixative has poor penetration).
  • Prepare a mixture of 9 parts of B5 fixative and 1 part of 37% formaldehyde, to a total of 100 ml, in a small specimen container.
    • Do not use 10% formalin at this point.
  • Fix the tissue in B5/formaldehyde for 2 hours.
  • Pour off the B5/formaldehyde into the mercury waste container (NOT INTO THE SINK) and immerse the tissue in 10% formalin solution.

Touch prepsEdit

For potential lymphoid lesions, or any other malignancy, it may be useful to make touch preps.

  • Make a fresh cut through the lesion and touch a charged (“plus”) slide to the tissue.
  • Air-dry.
  • Fix in methanol (essentially instantaneous) and stain like a frozen section.
  • Some institutions will use Diff-Quik or some other stain for these. Follow local practice.
  • It may be a good idea to also make 1-2 smears from the cut surface (similar technique to making a smear in cytology).

CytogeneticsEdit

  • Do not place specimen into formalin prior to obtaining sample.
  • Cut a small fresh representative fragment (0.3-1 cm) from the lesion. 
  • Place into a labeled container with RPMI or 3X RPMI (3 antibiotics added to kill contaminant growth).
  • Send to cytogenetics for conventional karyotype and/or specific translocations or panel.

Return to Specimen Grossing Manual

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