Bone marrow - nonneoplastic
Infectious / inflammatory
Granulomatous inflammation

Topic Completed: 1 May 2014

Revised: 2 August 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Bone marrow granulomatous inflammation

Dragos C. Luca, M.D.
Page views in 2018: 4,074
Page views in 2019 to date: 4,834
Cite this page: Luca DC. Granulomatous inflammation. website. Accessed December 8th, 2019.
Definition / general
Clinical presentation and diagnosis
  • Associated with fever and anemia
  • Disorders with epithelioid granulomas:
    • Tuberculosis: generally large with central caseation and frequent giant cells; organisms rarely identified
    • Histoplasmosis: variably sized, caseation or giant cells in ~50% of cases; organisms rare to moderately abundant
    • Mycobacterium avium complex: variably sized, generally noncaseating; organisms usually abundant
    • Viral: small, ill defined, with no caseation or giant cells; rarely ring shaped; predominantly lymphocytes, plasma cells, immunoblasts
    • Lymphoma and other neoplasms: usually small epithelioid granulomas
    • Other conditions: posttherapy, immune disorders, bone marrow transplantation, BCG
Case reports
Microscopic (histologic) description
  • Variably sized but usually small, focal and nonnecrotic
  • Composed of cohesive clusters of histiocytes, usually with admixed lymphocytes, eosinophils, neutrophils
  • Granulomas often paratrabecular
  • Ring or "doughnut" granulomas: fibrin and inflammatory cells arranged around a central clear space; associated with Q fever (but not specific)
  • Lipid granulomas: frequent; up to 1μ; associated with sinusoids or lymphoid aggregates; macrophages with fat vacuoles of varying size; also lymphocytes, plasma cells, eosinophils; giant cells in 5%; lipogranulomas generally considered insignificant
  • Small and rare epithelioid granulomas may also be clinically insignificant
  • Larger epithelioid granulomas, especially if containing a central area of necrosis (caseation) are significant and usually indicate infection (Brucella, Rickettsia, fungi)
  • Ring granulomas are also significant and also likely infectious (Q fever, Brucella, typhoid, rare viral infections)
  • Granulomas with distinctive finely vacuolated cells (Virchow cells) in leprosy
  • Rarely, foreign body granulomas can occur
Microscopic (histologic) images

Images hosted on other servers:

Peritrabecular sarcoid-like lesion

Bone marrow ring granulomas

Infiltrating lobular carcinoma of breast: H&E and keratin


CML treated with interferon

Noncaseating BM granuloma

Multinucleated giant cell

Granuloma in BM aspirate smear

CD68 immunostain

Histoplasmosis - BM granuloma

Histoplasmosis - organisms visible on H&E

Histoplasmosis - GMS stain

Caseating tuberculous granulomas

  • CD68 highlights the clustering of histiocytes
Differential diagnosis
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