Gastrointestinal histoplasmosis complicating pediatric Crohn disease: A case report and review of literature

Table 2 Infectious mimics of inflammatory bowel disease¹

Infectious etiology	Gastrointestinal site	Routine stain	Ancillary stain(s)
Bacterial
E. coli, O157-H7[24]	Colon	H&E stain	Gram stain
Shigella spp.[25]	Colon
Salmonella spp.[26]	Colon, terminal ileum
Campylobacter spp.[27]	Colon, terminal ileum
Yersinia enterocolitica[28]	Colon, terminal ileum
Clostridiodes difficle[29]	Colon
Nesisseria gonorrhoeae[30]	Colorectal
Treponema pallidum[31]	Colorectal
Chlamydia trachomatis[32]	Colorectal
Aeromonas spp.[33]	Colon
Mycobacterial tuberculosis[34]	Gastrointestinal tract, mostly terminal ileum		Gram stain
			Acid-fast stain (Ziehl-Neelsen or Kinyoun)
Fungal
Cryptococcus spp.[35]	Terminal ileum	H&E stain	GMS stain
Histoplasma capsulatum[36]	Terminal ileum		PAS stain
Coccidioides spp.[37]	Colon
Paracoccidioides spp.[38]	Colorectal
Viral
Cytomegalovirus[39]	Jejunoileal	H&E stain	CMV immunostain
Herpes simplex virus[40]	Colorectal		HSV I/II immunostain
Parasite
Entamoeba histolytica[41]	Colon	H&E stain	Giemsa stain
Enterobius vermicularis[42]	Colorectal		Serology
Taenia saginata[43]	Ileum		Stool examination
Strongyloides stercoralis[44]	Colon
Anisakis spp.[45]	Ileum
Hookworm (Ancylostoma duodenale, Necator americanus)[46]	Jejunoileal

¹Adapted from Shojaei et al[47].

CMV: Cytomegalovirus; GMS: Grocott-Gomori’s Methenamine Silver; H&E: Hematoxylin and eosin; HSV: Herpes simplex virus; PAS: Periodic acid-Schiff.