Table 1.

Infectious causes of granulomas and the laboratory studies to consider to rule out infection.

1. Bacteria

Actinomyces Bartonella Borrelia burgdorferi Brucellosis Mycobacterium tuberculosis Non-tuberculous mycobacterium Nocardia Q fever Treponema pallidum Whipples disease

2. Fungi

Aspergillosis Blastomycosis Candida Cryptococcus Histoplasma

3. Parasitic

Leshmaniosis Schistosomiasis

4. Viral

Cytomegalovirus Epstein barr

Laboratory studies to rule out infection:

1. Histopathologic examination

Ziehl–Neelsen stain or Auramine–rhodamine fluorescence for mycobacteria Grocott methenamine silver stain for fungi TB PCR

2. Culture for bacteria (aerobic and anaerobic), fungi, mycobacteria

3. Serology for histoplasma, syphilis, lyme disease