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Tuesday 10 June 2003



Definition : Granuloma is a component of a specific form of chronic inflammation , called " granulomatous inflammation " observed in many diseases.

It is a round and well defined collection of immune cells known as macrophages (or histiocytes ).

Classically, granulomas form when the immune system attempts to wall off substances it perceives as foreign but is unable to eliminate. Such substances include infectious organisms including bacteria and fungi, as well as other materials such as keratin and suture fragments.

Digital slides

- UI:872 - Foreign body granuloma (Foreign body reaction)



Definition: A granuloma is a solid grouping of inflammatory cells coming together in a lump or solid structure resulting from injury or inflammation or infection. Thus, granulomas are loosely defined as collections of inflammatory cells.


- epithelioid granuloma

  • Epithelioid granulomas are well-demarcated and are composed of variable numbers of lymphocytes, occasional plasma cells, and prominent numbers of activated macrophages which have round to indented clear nuclei and abundant eosinophilic cytoplasm (epithelioid cells).

- tuberculoid granuloma / epithelioid and gigantocellular granuloma

- inflammatory granuloma

  • Inflammatory granulomas are usually smaller than the epithelioid type and are composed of a mixed inflammatory infiltrate consisting of lymphocytes, macrophages, and occasional plasma cells, neutrophils and eosinophils.
  • These granulomas may or may not be poorly demarcated. Although occasional multinucleated giant cells can be seen, they are much less frequent than in the epithelioid granulomas.
  • A combination of both epithelioid and inflammatory granulomas may be seen within the same biopsy specimen.

- necrotizing granuloma

- eosinophilic granuloma
- palisading granuloma
- giant cell reparative granuloma
- fibrin-ring granuloma
- angiocentric granuloma
- cholesterol granuloma
- foreign body granuloma (foreign body reaction )


- cutaneous granuloma

- digestive granuloma
- pulmonary granuloma
- genital granuloma


- Atlas of Granulomatous Diseases by Yale Rosen, M.D.

See also

- granulation tissue
- granulomatoses