Bone marrow - nonneoplastic
Benign changes
Polymorphous reactive lymphoid hyperplasia

Author: Xiangrong (Alex) Zhao, M.D., Ph.D. (see Authors page)

Revised: 12 July 2017, last major update March 2014

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PubMed Search: Polymorphous reactive lymphoid hyperplasia

Cite this page: Polymorphous reactive lymphoid hyperplasia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/bonemarrowpolymorphousreactive.html. Accessed August 18th, 2017.
Definition / general
  • Reactive lymphoid hyperplasia of bone marrow is characterized by an increase in benign appearing lymphocytes and can be polymorphous, comprising small to medium sized lymphocytes admixed with plasma cells, histiocytes and sometimes occasional immunoblasts, eosinophils and mast cells:
    • Variable peripheral blood lymphocytosis
    • May be due to either an interstitial increase in lymphoid cells or an increase in lymphoid aggregates
    • A specific example - hematogone hyperplasia:
      • Hematogones are precursor B cells with a high nuclear to cytoplasmic ratio, condensed chromatin pattern and no nucleoli
      • May be seen in variety of conditions especially in children
      • More common after chemotherapy in both adults and children
      • Can be difficult to distinguish from lymphoblasts in B cell acute lymphoblastic leukemia
  • Associated with immune cytopenia, collagen vascular disease, AIDS (historically) (Arch Anat Cytol Pathol 1991;39:137)
Other information
  • For these sections - Epidemiology, Pathophysiology, Etiology, Clinical features, Diagnosis, Laboratory, Radiology, Prognostic factors, Individual case reports and Treatment, please review these topics: lymphoid aggregates, persistent polyclonal lymphocytosis, plasmacytosis and systemic polyclonal B immunoblastic proliferation
  • Overall, clinical and morphologic features are indicative of a benign reactive process, immunohistochemical and flow cytometric analysis detect no aberrant antigen expression or loss and cytogenetic and molecular findings show no abnormalities or evidence of clonal rearrangement
Microscopic (histologic) description
  • Focal, poorly circumscribed, randomly distributed lymphoid aggregates
  • Lymphocytes may be irregular and accompanied by plasma cells, immunoblasts, eosinophils, endothelial cells, mast cells, histiocytes and epithelioid histiocytes
Differential diagnosis
  • Benign hematogone hyperplasia: described above
    • Can be difficult to distinguish from lymphoblasts in B cell acute lymphoblastic leukemia but patient age is important
      • Children normally have more lymphocytes (up to 35%) in bone marrow while in adults, the normal value for lymphocytes on marrow aspirate smear is 6 - 25% (Br J Haematol 1996;94:206)
  • Peripheral T cell lymphoma: clonal; rare in AIDS patients