1. Common pitfalls in bone marrow
biopsy based diagnostic approach
Dr. N. Varma
Prof. & Head - Hematology
PGIMER, Chandigarh

2. Bone marrow (BM) examination
• Gold standard investigation for diagnosing and
monitoring many hematological diseases
• Useful for investigating various non-hematological
conditions
• Combination of bone marrow aspirate and trephine
biopsy: fine cytological detail, the organization of
BM, and the presence of focal abnormalities

3. Good-to-have Information
• Accurate clinical information; context and questions being
asked; details of previous investigations
• For neoplastic diseases: ? primary diagnostic investigation/
staging procedure/ re-examination to assess response to
treatment (including transplantation)
• The type and timing of previous BM transplantation are
also important factors; kinetics of engraftment differ
between conditioning regimes and graft types
• Knowledge of the recent therapeutic use of growth factors
such as G-CSF; these may transiently have major modifying
effects on hemopoiesis that can mask or mimic genuine
pathology

4. Pitfalls in obtaining and interpreting
bone marrow aspirates
• BM aspiration done when not needed
• BM aspiration not done when needed
• BM aspiration done on the wrong site
• The clinical context not adequately assessed and the correct range
of tests is therefore not done on the aspirate
• False negative result as a consequence of a sampling error
• The aspirate is not interpreted together with the trephine
biopsy sections
• The aspirate is misinterpreted
– Problems relating to technical quality
– Correct stains not performed
– Features present not noted
– Misinterpretation of an adequate aspirate

5. Limiting factors for interpretation of BMB
• Inadequate clinical, hematological (blood and aspirate findings),
genetic and radiological information
• Inadequate specimen
– Too small
– Too crushed/distorted
– Both
– Poorly decalcified/processed
• Inadequate sections (thickness, number of levels)
• Inadequate stains (poor technical quality, range too limited)
• Insufficient experience to avoid common pitfalls (eg, differential
diagnosis of granulomas or fibrosis)
• Insufficient confidence to avoid concluding ‘consistent with’
• ‘Invisible’ pathology
• Forgetting to look at the bone trabeculae and stroma

6. A systematic approach to diagnosis is
required for:
• Assessing patterns of lymphoid infiltration associated
with various lymphomas, especially small B-cell
lymphomas
• D/D of granulomatous pathologies
• Assessing key histological features of myelodysplastic
and myeloproliferative haemopoiesis
• D/D of bone marrow fibrosis
• D/D of hypoplasia/aplasia

7. Few representative examples will be shown
• Assessment of focal lesions
• Differentiation between reactive lymphoid infiltrate and NHL
• Differentiation between reactive and malignant plasma cells
• Identification of malignancies with associated fibrosis
• Effect of growth factors
• Differentiation between hematogones and blasts
• Differentiation between megaloblastic anemia and acute leukemia
• Differentiation between aplastic bone marrow and hypoplastic
myelodysplastic syndrome or hypoplastic acute leukemia
• Identification of lymphomas having a tendency for intravascular
infiltration in the BM
• Subtle amyloid deposition
• Differentiation of macrophage infiltrates and other pathologies that
resemble granulomatous infiltration
• Procedure related artefacts

8. Take home message
• Integration of clinical, laboratory and imaging information
• Not to assess histology in isolation
• Components of an integrated approach to interpretation are:
– A trephine core of adequate size with minimal disruption by trauma caused
during collection.
– Access to detailed clinical information and results of additional tests (specially,
peripheral blood cell counts, blood and BM aspirate cytomorphology, flow
cytometry, cytogenetic analysis and radiological imaging).
– Systematic assessment of all BM components, including trabecular bone and
interstitial stroma.
– Awareness of pathologies that may be ‘invisible’ in trephine specimens
without immunostaining.
– Use of preselected antibody panels for immunostaining and familiarity with
the expected results, including controls.
– Experience in interpreting additional molecular studies, such as clonality PCR
and fluorescence in-situ hybridisation, in the particular context of decalcified
tissue.
– Familiarity with the major patterns of bone marrow involvement by reactive
and neoplastic conditions and their differential diagnosis.
– A collaborative approach to working with diverse clinical and laboratory
colleagues.