Table 1.

Patterns of granulomatous inflammation and commonly associated etiologies.

Pattern of Inflammation	Associated Etiology
Foreign Body	Talc, starch, suture, hyaluronic acid (and other injectable fillers)
Necrotizing Granulomas	Infectious:Coccidioides immitis/C. posadasii, Cryptococcus neoformans/C. gattii, Histoplasma capsulatum, Blastomyces dermatitidis, Aspergillus spp., Mucorales, Mycobacterium tuberculosis, Non-tuberculous mycobacteria, Brucella spp., Nocardia spp., Yersinia spp., Bartonella henselae, Pneumocystis jiroveci, Echinococcus granulosus, xanthogranulomatous pyelonephritis+
	Autoimmune: Rheumatoid nodule, granuloma annulare, necrobiosis lipoidica, granulomatosis with polyangiitis
Non-Necrotizing Granulomas	Infectious*:Candida albicans (hepatosplenic candidiasis), C. immitis/C. posadasii, Coxiella burnetii, cytomegalovirus, M. tuberculosis, non-tuberculous mycobacteria including M. leprae (tuberculoid forms), Schistosoma spp., Toxoplasma gondii, Rickettsia spp., Salmonella typhi, hepatitis A & C virii, Autoimmune: Sarcoidosis, Churg Strauss, giant cell arteritis, systemic lupus erythematous, Crohn disease, primary biliary cirrhosis, orofacial granulomatosis, rosacea, granuloma annulare Toxic: actinic granuloma, berylliosis, zirconium, hot tub lung Drug: Bacillus Calmette-Guérin, Non-steroidal anti-inflammatory drugs, antibiotics, methotrexate Other: Lymphoid interstitial pneumonia, hypersensitivity pneumonitis, chronic lymphocytic leukemia
Suppurative Granulomas	Infectious: Actinomyces spp., Dirofilaria spp., Acanthamoeba spp., Balamuthia mandrillaris, B. henselae, B. dermatitidis, Brucella spp., Chlamydia trachomatis (serotypes L1, L2, L3 causing lymphogranuloma venereum), dematiaceous fungi causing chromoblastomycoses and phaeohyphomycosis, non-tuberculous mycobacteria, Francisella tularensis, Prototheca spp., Sporothrix schenckii, Paracoccidioides brasiliensis, Yersinia spp., Enterobius vermicularis
Histiocytic response, no granulomas	Infectious: Tropheryma whipplei, Listeria monocytogenes, non-tuberculous mycobacteria including M. leprae (lepromatous forms), H. capsulatum, Leishmania spp., Rhodococcus spp. (with malakoplakia) Other: Langerhans cell histiocytosis, granulomatous mycosis fungoides, juvenile xanthogranuloma, reticulohistiocytoma, Rosai Dorfman, pineal germinoma, seminoma/dysgerminoma, dendritic cell sarcoma, Erdheim-Chester disease, hemophagocytic lymphohistiocytosis, histiocytic sarcoma, interdigitating cell sarcoma, Langerhans cell sarcoma

*Entities may appear as well formed granulomas or histiocytic response.⁺Can present as necrotizing or non-necrotizing.