Bone marrow - nonneoplastic
Alterations in cellularity

Author: Dragos Luca, M.D. (see Authors page)

Revised: 7 July 2017, last major update October 2013

Copyright: (c) 2002-2017,, Inc.

PubMed Search: Bone marrow hypercellular [title]

Cite this page: Hypercellularity. website. Accessed October 16th, 2018.
Definition / general
  • A finding, not a diagnosis
  • Usually reactive (infection, blood loss) but also other benign or malignant causes
  • Benign causes:
    • Affecting predominantly one hematopoietic line:
      • Erythroid hyperplasia: often due to hemolytic anemia, high altitude or hypoxia of any other cause, renal disease, hemoglobinopathies, familial polycythemia
      • Myeloid hyperplasia: infections, compensatory hyperplasia after cell destruction, chronic blood loss, other stressors, drugs (G-CSF)
      • Megakaryocytic hyperplasia: often due to immune thrombocytopenia but also other types of thrombocytopenia; megakaryocytes may have striking nuclear changes
  • Malignant causes:
    • Affecting predominantly one hematopoietic line:
      • Erythroid: polycythemia vera, dysregulated erythropoietin production by various neoplasms
      • Myeloid: myeloid neoplasms (AML, CML, MDS, other MPD besides CML)
      • Megakaryocytic: MPD (essential thrombocythemia, CML, primary myelofibrosis), acute megakaryoblastic leukemia
  • Other causes include lymphoma, metastases
Microscopic (histologic) description
  • Increased hematopoiesis
  • Reduced adipose tissue
Microscopic (histologic) images

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Megaloblastic anemia