Bone Marrow & Stains

Question 1

Retrogression

Answer 1

Process of replacing the active marrow by fat tissue during development; results in restrictive active marrow sites.

Question 2

State the 3 main indications for a bone marrow evaluation.

Answer 2

• pt with solid malignant tumors ( ex. Lymphomas, carcinomas & sarcomas, with “Mets” to B.M.
• as part of initial workup of unexplained increased or decreased in RBCs, WBCs, & or plts.
• as part of differential diagnosis for infections that manifest clinically as “fevers of unknown origin”.

Question 3

Evaluate the process of collecting a bone marrow sample.

Answer 3

Performed less than 24 hrs before procedure, a CBC and manual differential are performed.
- biopsy kit into pt room.
- general sedation administered
- area washed with soap, antiseptic applied & site draped with sterile towels
- local anesthetic (typically 2% lidocaine) injected into the skin over the intended site.
- once numb, local anesthetic is injected into bone surface at selected site
- skin incision , doctor inserts needle into bone marrow cavity
- inner needle (obturator) removed
- vacuum applied by pulling syringe 1St B.M is aspirated & then trephine core biopsy is removed
- smears made by pouring a drop onto glass slide. B.M. Seen as gray particles floating in amount blood & fat droplets.
- marrow pieces removed with foreceps >2 clean glass slides then pulled opposite directions “pull smears”
- direct smears with drops remaining in syringe
- core biopsies removed
- remaining aspirate used for cytogenic workups

Question 4

List the preferred locations for bone marrow tap, in order of preference.

Answer 4

1. Posterior iliac crest (adults & children)
2. Sternum (adults)
3. Vertebrae ( in adults)
4. Tibia (children <1 yr only)

Question 5

Distinguish the 5 cell types found in NORMAL B.M.

Answer 5

• developing hematopoietic cells ( blasts of all types,
• macrophages or histiocytes- lrg cells with abundant cytoplasm & debris-filled vacuoles & irregular “spreading” shape.
• Megakaryocytes
• osteoblasts
• osteoclasts

Question 6

Assess the 7 aspects of a routine B.M.

Answer 6

1. Cellularity
2. Differential cell count
3. Type & concentration of abnormal aggregates
4. # & morphology of megakaryocytes
5. Presence & degree of fibrosis
6. Presence of abn intra or extra cellular material
7. Presence of abn changes in bony ultra structure
   ** procedure usually done by pathology but can be done in hematology department of oncology centers. **

Question 7

Evaluate how one can verify that B.M. Aspirate has been obtained.

Question 8

hyperplastic

Answer 8

abnormal increased number of cells caused by increased cellular division or abnormal retention.

Question 9

What is % of Myeloid/erythroid cellular layer when mixed and centrifuged?

Answer 9

5-8%

Question 10

M:E Ratio

Answer 10

ratio of volume of hematopoietic cells to the volume of marrow space for the patient’s age
N.R. Adults: 2.5:1 to 3.3:1
N.R. Infants: 5:1 to 6:1

Question 11

Which chemical test is useful for diagnosis of hairy cell leukemia?

Answer 11

Tartrate-resistant acid phosphatase test (TRAP) - performed on p.B. smears or BM.
“trap the hairy cells”

Question 12

Which chemical stain is useful for ID of Lymphoid from granuloctes and monocytes?

Answer 12

Peroxidase (myeloperoxidase) MPO

Question 13

Which chemical stain is useful for ID myelogenous and myelomonocytic leukemia?

Answer 13

Sudan Black B (SBB)