Bone Marrow Interpretation

Interpretation of Bone marrow aspiration and biopsy Bone marrow is the site where blood cells develop from totipotential haematopoietic stem cells. It consists of red marrow (haematopoetic tissue ) & yellow marrow (fat ) in a meshwork of vascular sinuses and highly branched fibroblasts . Production of blood cells commences in the yolk sac of embryo ,followed by liver & to some extent spleen from 2 months of gestation till birth and bone marrow after 7 months which forms the only important site after birth . Bone marrow is found in practically all bones at birth ,but in adults it is confined to the central skeleton ( vertebrae, sternum, ribs, skull, sacrum, pelvis ) and proximal ends of long bones (femur, tibia ,humerus). Bone marrow aspiration is the removal by suction of the marrow .  It is a simple and safe procedure.  Individual cell morphology is well preserved  But arrangement of cells in marrow & relationship between one cell & another is disrupted. So this is an important tool for cell morphology but not for architecture Bone marrow biopsy or needle core biopsy, is the removal of a small piece of intact bone marrow  Considered better than aspiration for evaluation of cell distribution and relationship between different cell types.  An important procedure when disease process is focal in nature

Bone marrow evaluation is not a baseline test, but rather a confirmatory test used to rule in or rule out specific hypotheses based on routine hematological investigations.

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Indications of bone marrow examination  Investigation of unexplained cytopenias o Unexplained leukopenia (neutropenia). o Unexplained thrombocytopenia. o Bicytopenia or pancytopenia.  Anemias esp. Megaloblastic anaemia  Investigation of atypical cells in the peripheral blood o Immature hematopoietic cells (blasts) in the blood o Atypical RBC (e.g., basophilic stippling, multiple Howell-Jolly bodies), WBC, or platelet morphology.  Persistent, unexplained marked increases in RBC, WBC, or platelet numbers in the peripheral blood.  Evaluation of infectious diseases such as leishmaniasis or histoplasmosis.  Investigation of hematological neoplasia o Differentiation, diagnosis, and staging of leukemias and lymphomas. o Diagnosis and staging of other neoplasias e.g. metastatic carcinoma.  Fever of unknown origin.  Immunophenotyping  Note :Bone marrow examination is not mandatory for diagnosis of leukaemias but is performed for subtyping , baseline blast cell percentage and cytogenetic analysis. Same is true for diagnosis of iron deficiency anaemia where simple biochemical tests along with peripheral blood findings are sufficient for diagnosis.

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Specific indications of bone marrow biopsy        

Dry tap Suspected aplastic anaemia Metastatic deposits Myelofibrosis Hairy cell leukaemia Inflammatory conditions like Granulomatous inflammation Lymphoma infiltration ( Hodgkins & Non hodgkins lymphoma) To see pattern of involvement in Chronic lymphocytic leukaemia

Preferred sites for bone marrow aspiration & biopsy  Posterior superior iliac spine (both aspiration and biopsy)  Sternum (aspiration only in adults)  Anterior iliac spine (both aspiration and biopsy)  Tibial tuberosity (aspiration in children