[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Inflammation](https://durgical.com/en/general-pathology/#a-inflammation) › Granulomatous inflammation: caseating vs non-caseating, the causes to know

[General pathology](https://durgical.com/en/general-pathology/) · [Inflammation](https://durgical.com/en/general-pathology/#a-inflammation)

# Granulomatous inflammation: caseating vs non-caseating, the causes to know

- Lesion

A granuloma is a tight ball of activated macrophages around something hard to kill; how it looks under the microscope points to the cause.

Updated 2026-11-01

## Key points

- Granuloma = epithelioid macrophages + giant cells + a rim of lymphocytes.
- Caseating: tuberculosis (and some fungi). Non-caseating: sarcoidosis, Crohn disease, foreign body, tuberculoid leprosy.
- Langhans giant cell = horseshoe of nuclei at the edge; foreign-body giant cell = scattered nuclei.
- Rule out infection (Ziehl-Neelsen, fungal stains, cultures) before calling it sarcoidosis.
- Stellate necrotising granulomas in a lymph node: cat-scratch disease.

## What it is

Granulomatous inflammation is a special form of chronic inflammation in which activated macrophages turn into epithelioid cells and gather into nodules, often with multinucleated giant cells and a rim of lymphocytes. The pathologist's task is to find the cause: central caseous necrosis suggests tuberculosis or a fungus, polarised light may reveal foreign material, and special stains look for acid-fast bacilli or fungi. The immune mechanism is covered in Inmunología; this page covers morphology and causes.

## Structure

- Epithelioid cells: activated macrophages with pale, elongated (slipper-shaped) nuclei and abundant pink cytoplasm, packed like an epithelium.
- Langhans giant cells have nuclei in a horseshoe at the periphery; foreign-body giant cells have scattered nuclei, often around visible material.
- Rim of lymphocytes (mostly CD4 T cells), sometimes plasma cells; older granulomas acquire a fibrous capsule and may calcify.
- Caseous necrosis: central, granular pink debris with no cell outlines; grossly white-yellow and cheese-like.
- Sarcoidosis: tight non-caseating granulomas; giant cells may hold asteroid or Schaumann bodies (not specific).

## Causes of granulomas

| Cause | Type of granuloma | How it is confirmed |
| --- | --- | --- |
| [Tuberculosis](https://durgical.com/en/conditions/tuberculosis/) | Caseating; Langhans giant cells | Ziehl-Neelsen stain (acid-fast bacilli), culture, molecular tests |
| [Leprosy (tuberculoid form)](https://durgical.com/en/conditions/leprosy/) | Non-caseating, along dermal nerves; few bacilli | Skin biopsy, Fite stain; the lepromatous form shows foamy macrophages full of bacilli instead |
| [Histoplasmosis](https://durgical.com/en/conditions/histoplasmosis/) | Caseating or non-caseating; small yeasts inside macrophages | Silver (GMS) or PAS stain, antigen tests, culture |
| [Paracoccidioidomycosis](https://durgical.com/en/conditions/paracoccidioidomycosis/) | Mixed suppurative and granulomatous; yeasts with multiple buds (‘ship's wheel’) | Silver stain, KOH preparation, culture |
| [Tertiary syphilis](https://durgical.com/en/conditions/syphilis/) | Gumma: necrotic centre with a rim rich in plasma cells | Serology; spirochetes are scarce |
| [Cat-scratch disease (Bartonella henselae)](https://durgical.com/en/conditions/bartonella-infections/) | Stellate necrotising granulomas with central neutrophils in lymph nodes | Serology, PCR, Warthin-Starry stain |
| [Sarcoidosis](https://durgical.com/en/conditions/sarcoidosis/) | Non-caseating, tight; many organs, hilar lymph nodes | Diagnosis of exclusion: negative stains and cultures |
| [Crohn disease](https://durgical.com/en/conditions/crohn-disease/) | Non-caseating, in the bowel wall | Biopsy with transmural inflammation and the clinical picture |
| [Granulomatosis with polyangiitis](https://durgical.com/en/conditions/granulomatosis-with-polyangiitis/) | Necrotising granulomas with vasculitis | c-ANCA (anti-PR3), biopsy |
| Foreign body (sutures, talc, wood) | Foreign-body giant cells around the material | Polarised light may show birefringent material |

## Markers

- Ziehl-Neelsen (acid-fast bacilli)
- Fite (M. leprae)
- GMS silver (fungi)
- PAS (fungi)
- Warthin-Starry (Bartonella, spirochetes)
- Polarised light (foreign material)

## Clinical notes

- In Colombia and Latin America tuberculosis, leprosy, histoplasmosis and paracoccidioidomycosis are endemic, so a granuloma in a biopsy calls for stains and cultures before sarcoidosis is diagnosed.
- Leprosy is a spectrum: strong Th1 immunity gives few, well-formed granulomas (tuberculoid); weak immunity gives sheets of foamy macrophages full of bacilli (lepromatous).
- Caseation is not proof of tuberculosis: fungi can caseate too, and tuberculosis in people with advanced HIV may form poor granulomas.

## Memory aid

Cheese means mycobacteria first: caseous necrosis points to tuberculosis (or a fungus); a clean, dry granuloma points to sarcoidosis, Crohn disease or a foreign body.

## Test yourself

Think of the answer, then tap the question to see it.

## How do Langhans giant cells differ from foreign-body giant cells?

Langhans cells have nuclei in a horseshoe at the periphery (typical of tuberculosis); foreign-body giant cells have scattered nuclei, often around visible material.

## Which stain looks for Mycobacterium tuberculosis in a granuloma?

The Ziehl-Neelsen (acid-fast) stain; culture and molecular tests add sensitivity.

## A child scratched by a kitten has a lymph node with stellate necrotising granulomas and central neutrophils. What is the cause?

Cat-scratch disease, caused by Bartonella henselae.

## Why is sarcoidosis a diagnosis of exclusion?

Its non-caseating granulomas are not specific; infections such as tuberculosis, fungi and leprosy must be ruled out with stains and cultures.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/general-pathology/granulomatous-inflammation-caseating-vs-non-caseating-the-causes-to-know/)

## Related

- [Chronic inflammation: causes, cells and features](https://durgical.com/en/general-pathology/chronic-inflammation-causes-cells-and-features/)
- [Patterns of necrosis: coagulative, liquefactive, caseous, fat, fibrinoid, gangrenous](https://durgical.com/en/general-pathology/patterns-of-necrosis-coagulative-liquefactive-caseous-fat-fibrinoid-gangrenous/)
- [Special stains in diagnosis: Congo red, Prussian blue, PAS, Ziehl–Neelsen, Gram](https://durgical.com/en/general-pathology/special-stains-in-diagnosis-congo-red-prussian-blue-pas-ziehl-neelsen-gram/)
- [Inflammation: the cardinal signs and its five steps](https://durgical.com/en/general-pathology/inflammation-the-cardinal-signs-and-its-five-steps/)

## Related conditions

- [Tuberculosis](https://durgical.com/en/conditions/tuberculosis/)
- [Pulmonary tuberculosis](https://durgical.com/en/conditions/pulmonary-tuberculosis/)
- [Sarcoidosis](https://durgical.com/en/conditions/sarcoidosis/)
- [Crohn disease](https://durgical.com/en/conditions/crohn-disease/)
- [Leprosy (Hansen disease)](https://durgical.com/en/conditions/leprosy/)
- [Histoplasmosis](https://durgical.com/en/conditions/histoplasmosis/)
- [Syphilis](https://durgical.com/en/conditions/syphilis/)
- [Paracoccidioidomycosis](https://durgical.com/en/conditions/paracoccidioidomycosis/)
- [Bartonella infections (cat-scratch disease, Carrion disease)](https://durgical.com/en/conditions/bartonella-infections/)
- [Schistosomiasis](https://durgical.com/en/conditions/schistosomiasis/)
- [Granulomatosis with polyangiitis](https://durgical.com/en/conditions/granulomatosis-with-polyangiitis/)
- [Giant cell arteritis](https://durgical.com/en/conditions/giant-cell-arteritis/)
- [Chronic granulomatous disease](https://durgical.com/en/conditions/chronic-granulomatous-disease/)
- [Hypersensitivity pneumonitis](https://durgical.com/en/conditions/hypersensitivity-pneumonitis/)
- [Spinal tuberculosis (Pott disease)](https://durgical.com/en/conditions/spinal-tuberculosis/)

## Elsewhere in DurgiPedia

- [Granulomatous inflammation](https://durgical.com/en/immunology/granulomatous-inflammation/)
- [Type IV hypersensitivity (delayed, T cells)](https://durgical.com/en/immunology/type-iv-hypersensitivity/)
- [Monocyte and macrophage](https://durgical.com/en/immunology/monocyte-and-macrophage/)
- [Interferon-γ](https://durgical.com/en/immunology/interferon/)
- [TNF-α](https://durgical.com/en/immunology/tnf/)
- [Microscopy and stains: H&E, PAS, trichrome, silver, immunohistochemistry](https://durgical.com/en/histology/microscopy-and-stains-h-y-e-pas-trichrome-silver-immunohistochemistry/)

## Microorganisms

- [Mycobacterium tuberculosis](https://durgical.com/en/microbiology/mycobacterium-tuberculosis/)
- [Mycobacterium leprae](https://durgical.com/en/microbiology/mycobacterium-leprae/)
- [Histoplasma capsulatum](https://durgical.com/en/microbiology/histoplasma-capsulatum/)
- [Paracoccidioides brasiliensis](https://durgical.com/en/microbiology/paracoccidioides-brasiliensis/)
- [Treponema pallidum](https://durgical.com/en/microbiology/treponema-pallidum/)
- [Bartonella](https://durgical.com/en/microbiology/bartonella/)
- [Schistosoma mansoni / S. haematobium / S. japonicum](https://durgical.com/en/microbiology/schistosoma-mansoni-s-haematobium-s-japonicum/)

[← All of general pathology](https://durgical.com/en/general-pathology/)

Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Tuberculosis](https://www.who.int/news-room/fact-sheets/detail/tuberculosis) (World Health Organization (WHO), 2025); [Leprosy](https://www.who.int/news-room/fact-sheets/detail/leprosy) (World Health Organization (WHO), 2026); [Sarcoidosis: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000076.htm) (MedlinePlus, US National Library of Medicine, 2026); [17.5 Inflammation and Fever](https://openstax.org/books/microbiology/pages/17-5-inflammation-and-fever) (OpenStax (Microbiology), 2016).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/granulomatous-inflammation-caseating-vs-non-caseating-the-causes-to-know/