Module 3- Bone Marrow Cytology/Biopsy
When is the erythroid series considered "mature"?
A cell in the erythroid series is considered mature when the cell becomes smaller the chromatin becomes clumped and the nucleus is eventually thrown out resulting in a erythrocyte. (Rubriblast, prorubricyte, rubricyte, metarubricyte, reticulocyte, erythrocyte)
When is the myeloid series considered "mature"?
A cell in the myeloid series is considered mature when the nucleus becomes progressively elongated and narrow and eventually becomes segmented. (Myeloblast, promylocyte, myelocyte, metamyelocyte, band neutrophil, segmented neutrophil)
Define leukemia.
A malignant progressive disease in which the bone marrow and other blood-forming organs produce increased numbers of immature or abnormal leukocytes.
What can the marrow be fixed in for histologic preparation?
Bone marrow can be fixed in a fixative containing mercuric chloride (B-5) or zinc-formalin.
What stains can be used for bone marrow cytology?
Bone marrow smears must be rapidly air dried and are usually stained with a Romanowsky-type stain or a Wrights stain (Diff-quick). If sending to a reference laboratory the smears are often stained with a Prussian blue.
What is the diagnosis of leukemia based on?
Diagnosis is based upon lymphoblastic infiltration of the bone marrow.
In what species is bone marrow examination the principal means of evaluating a response to anemia?
Equine
What stains can be used for bone marrow biopsy?
Hematoxylin-eosin stains and Giemsa stains are commonly used for core biopsy samples.
What are some indications for bone marrow examination?
Persistent unexplained pancytopenia neutropenia or thrombocytopenia non-regenerative anemia polycythemia unexplained presence of cells with abnormal morphologic features unexplained presence of immature cells on the differential blood film potential drug toxicities clinical staging of hematopoietic neoplasia
What percentages of the more mature RBCs and WBCs should be seen when examining bone marrow (i.e.: metamyelocyte, bands, neutrophils: rubricytes, metarubricytes)?
Rubricytes and metarubricytes usually comprise 80-90% of erythroid cells and metamyelocytes, bands and neutrophils comprise approx. 80-90% of myeloid cells.
How may the bone marrow be contaminated with peripheral blood?
The bone marrow can be contaminated with peripheral blood when attempting to withdraw to large of a sample size and applying too much negative pressure.
What are the two sites of choice for bone marrow collection in both the dog and cat?
The head of the humerus and the femoral head.
If a smear cannot be made immediately, what can be done with the sample, and how soon must the sample be examined?
The smear can be mixed with EDTA, however the smear must be made within one hour of collection.
How long after collection of the bone marrow should a smear be made, and how quickly will the marrow clot after collection?
The smear should be made immediately after collection, the marrow will clot rapidly after collection.
Is it necessary to collect peripheral blood when bone marrow is collected? Why or why not?
Yes it is necessary to collect peripheral blood, bone marrow status should be evaluated with the results of a differential white blood cell count from a concurrent peripheral blood film.
What is the M:E ratio?
ratio of myeloid elements to erythroid elements in the marrow