Etiology: Pancytopenia with Hypocellular Bone Marrow

Aplastic Anemia (see Aplastic Anemia)


  • Amegakaryocytic Thrombocytopenia
  • Down Syndrome
  • Dubowitz Syndrome
  • Dyskeratosis Congenita
  • Familial Aplastic Anemia
  • Fanconi Anemia
  • Preleukemia: monosomy 7, etc
  • Reticular Dysgenesis
  • Seckel Syndrome
  • Shwachman-Diamond Syndrome



Etiology: Pancytopenia with Cellular Bone Marrow

Bone Marrow Infiltration


(myelofibrosis is marrow fibrosis due to a primary hematologic process, while myelophthisis is marrow fibrosis due to a non-hematologic process)


Etiology: Hypocellular Bone Marrow with/without Pancytopenia


  • Peripheral Smear
    • Leukoerythroblastic Smear: smear with precursor cells of the myeloid and erythroid lineage, which usually indicates the presence of extramedullary hematopoiesis (predominantly in the spleen)
      • Etiology
        • Bone Marrow Infiltration
        • Myelofibrosis/Myelophthisis
        • Severe Stress: due to blood loss, infection, hemolysis, etc
      • Features
        • Immature Myeloid Cells
        • Megakaryocytic Fragments
        • Teardrop-Shaped RBC (Dacrocytes)
        • Immature Nucleated RBC
        • Anisocytosis
        • Poikilocytosis
        • Polychromasia
  • Bone Scan: sensitive for detecting bone mets
  • MRI: sensitive for marrow infiltration
  • Bone Marrow Biopsy
    • Myelofibrosis/Myelophthisis: “dry tap” on aspirate (as fibrosis makes aspiration difficult), biopsy usually diagnostic
    • Tuberculosis: caseating granulomas with positive acid-fast organisms (granulomas also may have typical Langhans-type giant cells with multiple nuclei)


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  • Bone marrow infiltration patterns and their prognostic significance in chronic lymphocytic leukemia: correlations with clinical, immunologic, phenotypic, and cytogenetic data. JCO June 1984 vol. 2 no. 6 562-570
  • Intrasinusoidal bone marrow infiltration: a common growth pattern for different lymphoma subtypes. Br J Haematol. 2002 Dec;119(4):916-22
  • Detection of bone marrow infiltration of lymphoma cells by fluorescence in situ hybridization. Clinica Chimica Acta Volume 344, Issues 1–2, June 2004, Pages 79–82