When Is Enough Enough?
[we updated this paper about 2000 & have misplaced that update]
While we do not calculate "adequacy QA data" as proposed
in this paper, we do process the specimens as detailed [here].
The essence of this paper was jointly contemplated for publication
in 1974. One of us [EBS] was invited in the early 1990s to co-author a Q-probes study
for the College of American Pathologists in order to assess the
status of bone marrow examinations within pathology departments
throughout the United States. The effort was discontinued when
significant institutional concern mounted up that the write-up
could potentially be misused as representing a "standard of
care document". Having missed that chance to trigger published
debate as to adequacy of bone marrow examination, we offer a potential
process and some commentary, especially in light of the managed-care
mentality that less work/effort is better and more cost effective.
Any bone marrow examination which accurately pinpoints one or
more significant diagnoses (whether a one-smear or comprehensive
exam) must be considered to be at least a partially adequate bone
marrow examination. Ideally, the approach to, and comprehensiveness
of, a bone marrow exam would be planned through the collaboration
of the clinical physician and the pathologist (morphologist interpreter)
in view of the differential diagnosis or management question in
the particular patient. History helps to focus the exam to answer
specific, implied questions. Short
of such, an array of techniques are variably applied in different
practice settings. A routine optimal approach broadly applicable
to general (and specialty) pathology practice has been previously
described1,17, having been utilized in that institution
for over 30 years. It has worked well in our lab since 1984.
Most diagnostic situations can be bracketed, even highly specifically
diagnosed, on a routine, properly acquired, comprehensive, technically
well-processed bone marrow specimen. Special studies are also easily
feasible, especially when preplanned, on such a sample. Otherwise,
a special-purposes specimen is needed. In the USA, such well-done specimens
are only 48 hours removed from world-class expert consultation,
should such become desired.
The morphologic state of hematopoie/sis is most consistently and
reliably interpreted when smears of (1) peripheral blood and (2) bone marrow
(cytologic manifestations) are compared with (3) sections of marrow
(histologic manifestations) and interpreted by a physician trained
in morphologic hematology.17 Yet, in an individual patient
encounter, these three standard preparations of the morphology
of hematopoiesis (peripheral blood smears, marrow smears, marrow
sections) are sometimes subject to split interpretations, each
component reviewed by different persons (located even in different
geographic locations) with varying expertise. In view of the adult
hematopoietic system being a 1600-3700 gram organ, sample adequacy
often is suboptimal, especially in the search for focal disease.
MRI has the capability of adding to marrow assessment; ultrasound
exams can quickly/accurately detect splenomegaly. Intuitively, the patient would be best served when this specialized morphologic
interpretation and results of other specialized studies are collated
(unified) into a final comprehensive report, a report detailing
the study adequately7,8,11. Knowledge of specifics of
original malignancy diagnoses may be critical in optimizing workups
and diagnostic consultation.9,16 Turnaround time for
preliminary and final reporting deserves attention.
One might measure group performance within a single practice or,
more broadly, by a large multi-practice survey retrospectively
assessing 30 completed bone marrow studies with one or more of
10 diagnoses (to include diffuse and focal disease) and responses
to a series of questions. Quantity or total surface area of bone
marrow examined is especially important for detecting focal disease5,6.
Comprehensiveness of the bone marrow exam can be more generally
calculated as follows (since the weighting of any particular element
of the formula would vary by the final diagnosis, the formula is
An institutional commitment to "thoroughness" can
then be numerically expressed using a double number: a comprehensiveness
number of 15 and a medium intensity number of 3 would be expressed
as a "thoroughness number" of 15/3.
Is medium, much less highest intensity, effort worth the time,
energy and expense? In our practice, this highest intensity (4
points) effort breaks out as follows with increased increment estimates:
a. Medical technologist time increment per case beyond "low":
estimated at 30-45 minutes, actual technologist time.
b. Histotech time increment per case beyond "low": estimated
at 15 minutes actual technologist time.
c. Pathologist/morphologist time increment per case beyond "low":
5-10 minutes actual time.
Specimen: Once into the routine, thoroughness
is as easy to carry out as non-thoroughness. And, the many possible
artifacts induced in marrow are more likely to be interpretatively
compensated for in a thorough exam. Aspirates can be faulty by
in vitro clotting or peripheral blood dilution, or by smears being
too thick or improperly fixed and stained. The slides of a 1 or
2 slide case can break or be lost. If one aspirates and then biopsies
from the aspirate site (or very closely nearby), there is a risk
of confusion through intramedullary hemorrhage or negative-pressure
evacuative disruption.2,18 We recommend biopsy first
followed by aspiration from a second, even nearby site.6,17,18 Trephine
biopsies in older patients often show a naturally hypocellular
2-4 mm subcortical fatty zone2; the particle cell block
or clot section may compensate by showing deeper, cellular marrow.
Whereas B5 fixative is the fixative of choice for bone marrow immuno-staining
and general morphology3, B5 and the decalcification
process can leach stainable iron out of the specimen (we continue
to use a mercury-based fixative). Smears for iron stain from aspirates
left in EDTA too long may also under-represent iron stores due
to iron leaching. The centrifuged aspirate fat layer smear reflects
reticulo-endothelial iron; and we have found this to be a significantly
positive preparation when iron stores appear, by comparison, to
be much less (or even absent) in the other types of preparations.
Routine paraffin-embedded processing is preferred.2,4 I
have found different smear fixation methods to cause significant
variations in apparent iron content and sideroblasts percentages,
more so than expected. This can be problematic in the discrimination
between iron positive bone marrow with low sideroblast count indicating
the impaired uptake of chronic disease anemia versus marrows which
are otherwise non-iron-poor: is the sideroblasts percentage actually
normal or reduced?14 Iron content grading systems exist.18
Finally, until proven to the contrary, the old axiom "it
is better to have it and not need it than to need it and not have
it" applies: don't throw anything away before the case is
fully signed out! For example, a particle cell block fixed in B5
fixative using aspirated marrow in an EDTA tube left out overnight
at room temperature can, in a pinch, give information as to cellularity
or presence of a granuloma or metastatic malignancy.
Our hemato-oncologists obtain Jamshidi trephine biopsy cores:
the average non-staging marrow biopsy is 0.9 cm long; and staging
marrows average 1.2 cm long. A 1.5 to 2.0 cm trephine core is generally
considered adequate11 to optimal7,17 and
less than adequate if shorter than 1 cm (unless it results in a
pertinent positive diagnosis).10,18 At least in the
case of diffuse large cell lymphoma, bilateral sampling has shown
that positivity occurs in only one of the two biopsies in 50% of
cases.9 A negative staging marrow is best considered
to be a "true negative" when sampling two sites, each
yielding the equivalent of a trephine core 2 x 0.2cms19 (and
special marker stains and other parameters being negative, as previously
discussed). This thoroughness is even proposed as cost effective.20 The
most accurate assessment of bone marrow cellularity8 and
proper architectural geographic location of cell lines is by way
of the bone marrow biopsy specimen. Logically, a search for focal
disease would imply the need of an examination of a greater quantity
(histological surface area) of bone marrow than evaluation of diffuse
systemic disease. Again, bilateral staging biopsies have long been
recommended in lymphoma staging.6,13 Immunoperoxidase
markers can label minimal but significant infiltrates of lymphoma,12 lobular
carcinoma,16 and minimal myeloma.21 Only
using routine studies can result in false-negative diagnosis in
a dismal 61% of lobular carcinoma cases!16 Acute leukemia
evaluations post-chemotherapy are best done with the trephine biopsy
where geographic presence of immature cells in paratrabecular regions
is more likely to reflect regeneration whereas such foci in medullary
regions may reflect residual/recurrent leukemia.22 In
the search for focal disease, cell block aggregation of ordinary
aspirate residual or, better, a special aspirate to provide a large
cell block15, can greatly increase bone marrow surface
area examined. Maneuvers to wash RBCs from the cell block particle
aggregate will make sectioning easier and remove the RBC source
of background peroxidases.15
Tissue culture, microbiological culture, cytogenetic studies,
flow cytometry studies, and other special studies are extremely
difficult to generally anticipate and cover for in a routine bone
marrow examination (collaboration is even more important in such
A high quality and thorough morphologic interpretation of bone
marrow has the potential for addressing hematological (and some
other disease categories, too) differential diagnoses more completely
than can be obtained through both direct and inferential information
garnered through other laboratory and clinical tests. A rapid preliminary
review of peripheral blood and bone marrow smears may be able to
answer the bottom-line, highly focused question of the clinician.
If the clinician thusly is supported with rapid preliminary diagnosis
turn-around times followed by a comprehensive bone marrow diagnostic
sign-out within 48 hours or less, the bone marrow is likely to
become a more worthwhile and frequently used component of clinical
workups. Our sense of pathologist-clinician colleagueness is enhanced;
and patient care decisions made quicker with rapid turn-around
time, especially in situations such as: rule out acute leukemia,
thrombocytopenia, and pancytopenias. We are aware that rapid turn-around
time is becoming increasingly important in many pathology practices.
The Bethesda System for pap smear reporting has (under the CLIA
regulations) forced pathologists and gynecologists to address the
issue of specimen/history adequacy of a pap smear. It is hoped
that this write-up will encourage physicians to begin to define
the adequacy of a particular bone marrow exam in view of the clinical
indication for the exam as well as the statistical information
uncovered in evaluating thoroughness in your pathology practices.
Unlike the massive increase in intensity needed to achieve 100%
oxygen saturation of hemoglobin, thoroughness in morphologic hematology
is easy once beyond the initial stage of gearing up and systematizing
1. R.K. Brynes, R.W. McKenna, R.D. Sundberg, Bone Marrow Aspirate
and Trephine Biopsy: An Approach to a Thorough Study, American
Journal of Clinical Pathology, 1978, 70(5): 753-759.
2. R.D. Brunning in Ackerman's Surgical Pathology, 7th Ed., Juan
Rosai, The C.V. Mosby Co., 1989, Chapter 23, pgs. 1379- 1453.
3. R.D. Brunning at Mayo Medical Laboratories Conference: Hematopathology
Updates, Scottsdale, Ariz. 24 Sept. 1993,
4. K.C. Gatter, A. Heryet, D.C. Brown, D.Y. Mason, Is It Necessary
to Embed Bone Marrow Biopsies in Plastic For Hematological Diagnosis?,
Histopathology, 1987, 11:1-7.
5. B.A. Chabner, R.I. Fisher, R.C. Young, V.T. DeVita, Staging
of non-Hodgkin's Lymphoma. Seminars in Oncology, 1980, 7:285.
6. R.D. Brunning, C.D. Bloomfield, R.W. McKenna, and L. Peterson,
Bilateral Trephine Bone Marrow Biopsies in Lymphoma and Other Neoplastic
Diseases. Annals of Internal Medicine, 1975, 82:365-366.
7. J. R. Krause, Bone Marrow Biopsy, 1981, Churchill Livingstone,
8. J.I. Dickstein & J.W. Vardiman, Issues in the Pathology
and Diagnosis of the Chronic Myeloproliferative Disorders and the
Myelodysplastic Syndromes, AJCP 99(4): 513-525, April 1993.
9. G.F. Hodges, et.al., Bone Marrow Involvement in Large-cell
Lymphoma, Prognostic Implications of Discordant Disease, AJCP,
101(3):305-311, March 1994.
10. C.L. Wright, & K. Rizkalla, Bone Marrow Biopsy Length
in Staging of Lymphomas, Modern Pathology, 1994, 7(1): 124A, 1994.
11. B.H. Hyun, et.al., Bone Marrow Examination: Techniques and
Interpretation, in Hematology/Oncology Clinics of North America,
12. M.Fraga, et.al., Bone Marrow Involvement in Anaplastic Large
Cell Lymphoma..., AJCP, 103(1): 82-89, 1995.
13. J.A. Hinson & M.C. Perry, Small Cell Lung Cancer, CA Cancer
Journal for Clinicians, 43(4): 216-225, 1993.
14. R.D. Sundberg & H. Browman, The Application of the Prussian
Blue Stain to Previously Stained Films of Blood and Bone Marrow,
Blood, 10:160-166, 1955.
15. E.B. Shaw, Agar Processing of Bone Marrow Aspirate Material,
Laboratory Medicine, 25(1):39, 1994.
16. M.A. Bitter, et.al, Bone Marrow Involvement by Lobular Carcinoma
of the Breast Cannot Be Identified Reliably by Routine Histologic
Examination Alone, Human Pathology, 25(8): 781-788, 1994.
17. R.D. Brunning & R.W. McKenna, Atlas of Tumor Pathology...Tumors
of the Bone Marrow (AFIP 3rd Series Fascicle 9), Armed Forces Institute
of Pathology, Washington, D.C., 1994, 496 pages.
18. G.R. Lee, et.al., Wintrobe's Clinical Hematology, 9th
Ed., Lea & Febiger, 1993, 2324 pages.
19. R.W. McKenna & J.A. Hernandez, Bone Marrow in Malignant
Lymphoma, in Hematology/Oncology Clinics of North America,
20. G.E. Richardson, et.al., Application of an Algorithm for Staging
Small-Cell Lung Cancer Can Save One-Third of the Initial Evaluation
Costs, Archives of Internal Medicine, 153(3):329-337, 1993.
21. D. M. Menke, et.al., Bone Marrow Aspirate Immunofluorescent
and Bone Marrow Biopsy Immunoperoxidase Staining of Plasma Cells
in Histologically Occult Plasma Cell Proliferative Marrow Disorders, Archives
of Pathology and Laboratory Medicine, 118(8): 811-814, August,
22. J.H. Beckstead, The Bone Marrow Biopsy: A Diagnostic Strategy,
Archives of Pathology and Lab Medicine, 110(3):175-9, March 1986.
23. S.S. Sung, Immuno-architecture of Normal Human Bone Marrow:
A study of frozen and fixed tissue sections, Human Pathology, 23(6):
686-694, June 1992.
Ervin Shaw, M.D. and John B. Carter,
M.D. 2/95 (distributed at April 1995 CAP/ASCP meeting in Orlando)
Lexington Medical Center
2720 Sunset Blvd.
West Columbia, SC 29169
Note: Pathology Associates of Lexington, P.A. at Lexington Medical
Center, West Columbia, S.C. has long utilized this approach to
bone marrow processing and interpretation.