[1][6] In medical practice, doctors occasionally use the term granuloma in its more literal meaning: "a small nodule".

Since a small nodule can represent any tissue from a harmless nevus to a malignant tumor, this use of the term is not very specific.

Similarly, radiologists often use the term granuloma when they see a calcified nodule on X-ray or CT scan of the chest.

The most accurate use of the term granuloma requires a pathologist to examine surgically removed and specially colored (stained) tissue under a microscope.

[citation needed] The other key term in the above definition is the word "organized" which refers to a tight, ball-like formation.

These include lymphocytes, neutrophils, eosinophils, multinucleated giant cells, fibroblasts, and collagen (fibrosis).

[2][3] Infections characterized by granulomas include tuberculosis, leprosy, histoplasmosis, cryptococcosis, coccidioidomycosis, blastomycosis, and cat-scratch disease.

[citation needed] An important feature of granulomas is whether or not they contain necrosis, which 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, appears cheese-like ("caseous"), and is typically a feature of the granulomas of tuberculosis.

[2] When Cryptococcus infection occurs in persons whose immune systems are intact, granulomatous inflammation is typically encountered.

Rheumatic fever is a systemic disease affecting the periarteriolar connective tissue and can occur after an untreated group A, beta-hemolytic streptococcal pharyngeal infection.

Sarcoidosis is a disease of unknown cause characterized by non-necrotizing ("non-caseating") granulomas in multiple organs and body sites,[12] most commonly the lungs and lymph nodes within the chest cavity.

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.

[15] Pneumocystis infection in the lungs is usually not associated with granulomas, but rare cases are well documented to cause granulomatous inflammation.

Granulomas may form, though, when food particles or other particulate substances such as pill fragments are aspirated into the lungs.

The resultant granulomas are typically found around the airways (bronchioles), and are often accompanied by foreign body-type, multinucleated giant cells, acute inflammation, or organizing pneumonia.

Typically, a central zone of necrobiotic generation of collagen is seen, with surrounding inflammation and mucin deposition on pathology.