A granuloma - plural granulomas or granulomata - is a discrete region of granulomatous inflammation defined by its histology after biopsy:
- epitheloid cells at its centre
- fusion of epitheloid cells to form a foreign body giant cell - the key feature
There may also be:
- lymphocyte mantle surrounding epitheloid cells
- evidence of aetiological agent e.g. tuberculosis bacillus
- fibroblast proliferation with or without fibrin deposition
- plasma cells
- less frequently, neutrophils
A tuberculous granuloma is termed a tubercle. Rheumatoid nodules of rheumatoid arthritis contain granulomas.
The causes of granulomas are detailed under granulomatous inflammation in the submenu.
Last reviewed 01/2018