Picture of a granuloma (without necrosis) as seen through a microscope on a glass slide. The tissue on the slide is stained with two standard dyes (hematoxylin: blue, eosin: pink) to make it visible. The granuloma in this picture was found in a lymph node of a patient with Mycobacterium avium infection
Classification and external resources
Specialty Pathology
ICD-10 L92
ICD-9-CM 686.1, 709.4
MeSH D006099

Granuloma[1] (plural granulomas or granulomata) is an bacteria and fungi, as well as other materials such as keratin and suture fragments.[1][2][3][4] The adjective granulomatous means characterized by granulomas.


  • Definition 1
  • Diseases with granulomas 2
    • Tuberculosis 2.1
    • Leprosy 2.2
    • Schistosomiasis 2.3
    • Histoplasmosis 2.4
    • Cryptococcosis 2.5
    • Cat-scratch disease 2.6
    • Rheumatic Fever 2.7
    • Sarcoidosis 2.8
    • Crohn's disease 2.9
    • Listeria monocytogenes 2.10
    • Pneumocystis pneumonia 2.11
    • Aspiration pneumonia 2.12
    • Rheumatoid arthritis 2.13
    • Granuloma annulare 2.14
    • Foreign-body granuloma 2.15
  • Granulomas associated with vasculitis 3
  • See also 4
  • Notes 5
  • References 6
  • External links 7


In macrophages.[1][5]

In medical practice, doctors occasionally use the term "granuloma" loosely to mean "a small nodule". Since a small nodule can represent anything from a harmless nevus to a malignant tumor, this usage of the term is not very specific. Examples of the inaccurate use of the term granuloma are the lesions known as vocal cord granuloma, pyogenic granuloma and intubation granuloma, all of which are examples of granulation tissue, not granulomas. "Pulmonary hyalinizing granuloma" is a lesion characterized by keloid-like fibrosis in the lung, and is not granulomatous. Similarly, radiologists often use the term granuloma when they see a calcified nodule on X-ray or CT scan of the chest. They make this assumption since granulomas usually contain calcium, although the cells that form a granuloma are too tiny to be seen by a radiologist. The most accurate use of the term "granuloma" requires a pathologist to examine surgically removed and specially colored (stained) tissue under a microscope.

Macrophages (also known as histiocytes) are the cells that define a granuloma. They often, but not invariably, fuse to form multinucleated giant cells (Langhans giant cell).[6] The macrophages in granulomas are often referred to as "epithelioid". This term refers to the vague resemblance of these macrophages to epithelial cells. Epithelioid macrophages differ from ordinary macrophages in that they have elongated nuclei that often resemble the sole of a slipper or shoe. They also have larger nuclei than ordinary macrophages and their cytoplasm is typically more pink when stained with eosin. These changes are thought to be a consequence of "activation" of the macrophage by the offending antigen.

The other key term in the above definition is the word "organized" that refers to a tight, ball-like formation. The macrophages in these formations are typically so tightly clustered that the borders of individual cells are difficult to appreciate. Loosely dispersed macrophages are not considered to be granulomas.

All granulomas, regardless of cause, may contain additional cells and matrix. These include lymphocytes, neutrophils, eosinophils, multinucleated giant cells, fibroblasts and collagen (fibrosis). The additional cells are sometimes a clue to the cause of the granuloma. For example, granulomas with numerous eosinophils may be a clue to coccidioidomycosis or allergic bronchopulmonary fungal disease, and granulomas with numerous neutrophils suggest blastomycosis, granulomatosis with polyangiitis, aspiration pneumonia or cat-scratch disease.

In terms of the underlying cause, the difference between granulomas and other types of inflammation is that granulomas form in response to antigens that are resistant to "first-responder" inflammatory cells such as neutrophils and eosinophils. The antigen causing the formation of a granuloma is most often an infectious pathogen or a substance foreign to the body, but often the offending antigen is unknown (as in sarcoidosis).

Granulomas are seen in a wide variety of diseases, both infectious and non-infectious.[1][2] Infections that are characterized by granulomas include tuberculosis, leprosy, histoplasmosis, cryptococcosis, coccidioidomycosis, blastomycosis and cat scratch disease. Examples of non-infectious granulomatous diseases are sarcoidosis, Crohn's disease, berylliosis, granulomatosis with polyangiitis, Churg-Strauss syndrome, pulmonary rheumatoid nodules and aspiration of food and other particulate material into the lung.

An important feature of granulomas is whether or not they contain necrosis. Necrosis refers to dead cells that, under the microscope, appear as a mass of formless debris with no nuclei present. A related term, "caseation" (literally: turning to cheese) refers to a form of necrosis that, to the unaided eye (i.e., without a microscope), appears cheese-like ("caseous"), and is typically (but not uniquely) a feature of the granulomas of tuberculosis. The identification of necrosis in granulomas is important because granulomas with necrosis tend to have infectious causes.[1] There are several exceptions to this general rule, but it nevertheless remains useful in day-to-day diagnostic pathology.

Diseases with granulomas


The granulomas of [12]

Rheumatoid arthritis

Necrotizing granulomas can develop in patients with rheumatoid arthritis, typically manifesting as bumps in the soft tissues around the joints (so-called rheumatoid nodules) or in the lungs.[8]

Granuloma annulare

Granuloma annulare is a skin disease of unknown cause in which granulomas are found in the dermis of the skin. However, it is not a true granuloma. Typically there is a central zone of necrobiotic generation of collagen with surrounding inflammation and mucin deposition on pathology.

Foreign-body granuloma

A foreign-body granuloma occurs when a foreign body (such as a wood splinter, piece of metal, glass etc.) penetrates the bodies soft tissue followed by acute inflammation and formation of a granuloma.[13] In some cases the foreign body can be found and removed even years after the precipitating event.[14]

Granulomas associated with vasculitis

Certain inflammatory diseases are characterised by a combination of granulomatous inflammation and vasculitis (inflammation of the blood vessels). Both the granulomas as well as the vasculitis tend to occur in association with necrosis. Classic examples of such diseases include granulomatosis with polyangiitis (GPA) (previously referred to by the eponym Wegener's Granulomatosis[15]) and Churg-Strauss syndrome.

See also


  1. ^ From granule + -oma


  1. ^ a b c d e f Mukhopadhyay, S; Farver CF, Vaszar LT, Dempsey OJ, Popper HH, Mani H, Capelozzi VL, Fukuoka J, Kerr KM, Zeren EH, Iyer VK, Tanaka T, Narde I, Nomikos A, Gumurdulu D, Arava S, Zander DS, Tazelaar HD (Jan 2012). "Causes of pulmonary granulomas: a retrospective study of 500 cases from seven countries". J Clin Pathol 65 (1): 51–57.  
  2. ^ a b Woodard BH, Rosenberg SI, Farnham R, Adams DO (1982). "Incidence and nature of primary granulomatous inflammation in surgically removed material". American Journal of Surgical Pathology 6 (2): 119–129.  
  3. ^ Hunter DC, Logie JR (1988). "Suture granuloma". British Journal of Surgery 75 (11): 1149–1150.  
  4. ^ Chen KT, Kostich ND, Rosai J (1978). "Peritoneal foreign body granulomas to keratin in uterine adenocanthoma". Archives of Pathology and Laboratory Medicine 102 (4): 174–177.  
  5. ^ Adams DO (1976). "The granulomatous inflammatory response. A review". American Journal of Pathology 84 (1): 164–191.  
  6. ^ Paul Travers, Mark Walport (2008). Janeway's Immunobiology. Garland Science. p. 372. 
  7. ^ dental decks part II Edited by Nour
  8. ^ a b c d Mukhopadhyay S, Gal AA. (2010). "Granulomatous lung disease: an approach to the differential diagnosis". Archives of Pathology and Laboratory Medicine 134 (5): 669–690.  
  9. ^ Iannuzzi M, Rybicki BA, Teirstein AS (2007). "Sarcoidosis". New England Journal of Medicine 357 (21): 2153–2165.  
  10. ^ Cohen, Elizabeth (June 11, 2009). "Teen diagnoses her own disease in science class". CNN Health (Cable News Network). 
  11. ^ Hartel PH, Shilo K, Klassen-Fischer M, et al. (2010). "Granulomatous reaction to Pneumocystis jirovecii. clinicopathologic review of 20 cases". American Journal of Surgical Pathology 34 (5): 730–734.  
  12. ^ Mukhopadhyay S, Katzenstein AL (2007). "Pulmonary disease due to aspiration of food and other particulate matter: a clinicopathologic study of 59 cases diagnosed on biopsy or resection specimens". American Journal of Surgical Pathology 31 (5): 752–759.  
  13. ^ "Foreign Body Granuloma". Journal of Maxillofacial and Oral Surgery. March 2011. 
  14. ^ El Bouchti, I.; Ait Essi, F.; Abkari, I.; Latifi, M.; El Hassani, S. (2012). "Foreign Body Granuloma: A Diagnosis Not to Forget". Orthopedics (Hindawi Publishing Corporation) 2012.  
  15. ^ Falk, R.J., Gross, W.L., Guikkevin, L., et al. (2011) Granulomatosis with polyangiitis (Wegeners's): an alternative name for Wegener's granulomatosis, Ann Rheum Dis 70:704

External links

  • Atlas of Granulomatous Diseases Yale Rosen, MD

Aspiration pneumonia

Pneumocystis infection in the lungs is usually not associated with granulomas, but rare cases are well documented to cause granulomatous inflammation. The diagnosis is established by finding Pneumocystis yeasts within the granulomas on lung biopsies.[11]

Pneumocystis pneumonia

Listeria monocytogenes infection in infants can cause potentially fatal disseminated granulomas, called granulomatosis infantiseptica, following in utero infection.

Listeria monocytogenes

Crohn's disease is an inflammatory condition of uncertain cause characterized by severe inflammation in the wall of the intestines and other parts of the abdomen. Within the inflammation in the gut wall, granulomas are often found, and are a clue to the diagnosis.[10]

Crohn's disease

that impairs breathing; in the heart, it can lead to rhythm disturbances, heart failure and even death. pulmonary fibrosis Sarcoid granulomas can resolve spontaneously without complications or heal with residual scarring. In the lungs, this scarring can cause a condition known as [8]. However, these structures are not specific for sarcoidosis.Schaumann bodies structures termed lamellar or asteroid bodies). Sarcoid granulomas often contain star-shaped structures termed fibrosis are similar to the granulomas of tuberculosis and other infectious granulomatous diseases. However, in most cases of sarcoidosis, the granulomas do not contain necrosis and are surrounded by concentric scar tissue (sarcoidosis most commonly the lungs and lymph nodes within the chest cavity. Other common sites of involvement include the liver, spleen, skin and eyes. The granulomas of [9]


Rheumatic fever is a systemic disease affecting the peri-arteriolar connective tissue and can occur after an untreated Group A Beta hemolytic streptococcal pharyngeal infection. It is believed to be caused by antibody cross-reactivity.

Rheumatic Fever

pus forming, containing large numbers of neutrophils. Organisms are usually difficult to find within the granulomas using methods routinely used in pathology laboratories.

Cat-scratch disease

[8] When


[1] Granulomas are seen in most forms of


Some schistosome ova that are laid in intestinal and urinary venules backwash into the liver via the portal vein causing granuloma formation in the liver.


In leprosy, granulomas are found in the skin and tend to involve nerves. The appearance of the granulomas differs according to the precise type of leprosy.