Table 1: Etiologic causes of granulomas depending on the histopathologic characteristic.

Characteristic of granulomaDescriptionEtiologic causes

With necrosisMacrophages, multinucleated giant cells, lymphocytes, and central necrosis; calcifications may be presentTuberculosis, chronic fungal infections (such as histoplasmosis, coccidioidomycosis, blastomycosis), Wegener's granulomatosis

With necrosis and eosinophilsMacrophages, multinucleated giant cells, lymphocytes, eosinophils, and necrosisParasites (including schistosomiasis, fasciolosis), sometimes some of the chronic fungal infections mentioned above

With stellate or geographic necrosisMacrophages, multinucleated giant cells, lymphocytes, neutrophils, central necrosis that takes a stellate shapeTularemia, bartonellosis, lymphogranuloma venereum, actinomycosis, chronic granulomatous disease

With suppurative inflammationMacrophages, lymphocytes, abundant neutrophils, and different amounts of necrosisTularemia, listeriosis, acute fungal infections

With abundant plasma cellsMacrophages, multinucleated giant cells, lymphocytes, plasma cells, and different amounts of necrosisSyphilis

Foamy macrophage aggregatesFoamy macrophages with minimal necrosis and other inflammatory cellsAtypical mycobacteria (MAI), Whipple disease, Rhodococcus equi, lepromatous leprosy

Epithelioid granuloma with minimal or no necrosisSmall, macrophages, multinucleated giant cells, lymphocytesLeishmaniasis, sarcoidosis, lupus, hepatitis C

Epithelioid granuloma with minimal or no necrosis but presence of eosinophilsSmall, macrophages, multinucleated giant cells, lymphocytes, eosinophilsRejection after transplant, response to medications

Ill definedSmall groups of macrophagesHodgkin's disease, metastasis

Lipid granulomas Macrophages with lipid vacoules, lymphocytes, may have some necrosis including fibrin depositionLipid containing foods, mineral oils, reactions to medications, toxoplasmosis

Granulomas with a vacuole surrounded by fibrinMacrophages, multinucleated giant cells, lymphocytes, neutrophils, lipid vacuole (clearing) surrounded by fibrinQ fever, rarely: leishmaniasis, toxoplasmosis, cytomegalovirus, typhoid