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

Table 1 Reports of histoplasmosis mimicking inflammatory bowel disease in pediatric immunocompetent patients: Cases published between 1970–present (including current case)

Ref.	No. of cases	Age/Sex	Clinical presentation	Initial concern	Immune status	Laboratory investigations
Soper et al[23], 1970	2	15/M	Periumbilical pain with radiation to back; prior exposure to Coccidioides and Histoplasma	Presumed CD	Immunocompetent	Histoplasma antibody titers 1:1024
		13/M	Abd pain, bilious vomiting, weight loss, fever; prior exposure to Histoplasma	Presumed CD	Immunocompetent	Not performed
Alberti-Flor and Granda[18], 1986	1	16/M	Abd pain, diarrhea, weakness, fever; history of Job syndrome	Presumed CD	Hyper-IgE syndrome	Complement fixation 1:64; yeast antigen 1:8; preciptin (H/M bands), GMS+ yeast forms (resection specimen)
Steiner et al[19], 2009	1	14/F	Fatigue, abd pain, fever, weight loss	Presumed CD	Hyper-IgE syndrome	Urine Histoplasma antigen (8.34 ng/mL), Histoplasma complement fixation titers 1:32 (mycelial phase) 1:64 (yeast phase), preciptin (H/M bands), Yeast forms (terminal ileum, ileocecal valve)
Agarwal et al[20], 2015	1	7/F	Intermittent fever and chills, weight loss	Presumed CD	Immunocompetent	Yeast forms (peripheral blood), GMS/PAS+ yeast forms (bone marrow)
Kweyamba et al[21], 2016	1	4/M	Intermittent vague abd pain, anorexia, occasional vomiting and nausea; obstructing mesenteric chylous cyst	Intestinal obstruction	Immunocompetent	PAS+ yeast forms (cyst lining)
Acharyya et al[22], 2021	1	8/M	Colicky abd pain, weight loss, constipation, subsequent ileal stricture	Presumed intestinal tuberculsosis, unresponsive to antitubercular medication × 9 mo	Immunocompetent	GMS+ yeast forms (ileum, mesenteric nodes)
Current case, 2022	1	12/M	Abdominal pain × several months, weight loss, bloody diarrhea	Presumed CD	Immunocompetent	GMS+ yeast forms (colon)

6-MP: 6-mercaptopurine; abd: Abdominal; CD: Crohn disease; GI: Gastrointestinal; IBD: Inflammatory bowel disease; NR: Not reported; UC: Ulcerative colitis.

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.