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| Fungal granulomatous etiologies | Location in the gastrointestinal tract | Imaging findings | Histological findings |
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| Histoplasmosis | Ileocecal junction → colon, small intestine, and upper GI tract | Endoscopy
(i) Friable polypoid mass with focal erosion ranging from terminal ileum to rectum
CT abdomen
(i) Polypoid and apple core lesions with regional lymphadenopathy
(ii) Colonic skip lesions | (i) Clusters of macrophages localized in the lamina propria forming caseating granuloma-like lesions, containing engulfed intracellular yeast with narrow budding which is PAS+ and GMS+
(ii) It can also present as noncaseating granulomas but appear fewer in number (<2 granulomas per slide) with ragged borders. This is in contrast to Sarcoidosis, which demonstrates numerous granulomas (>10 per slide) with clearly defined, sharp borders |
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| Cryptococcosis | Esophagus, stomach duodenum (high preference) | Endoscopy
(i) A nonspecific patchy, friable, and erosive lesion with swollen villi in the duodenum | (i) Caseating granulomas with a moderate histiocytic response and minimal recruitment of lymphocytic and neutrophilic components with evidence of intracellular narrow budding yeast which stains positive for PAS, GMS, and Alcian blue |
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| Coccidioidomycosis | Peritoneum | CT abdomen
(i) Omental thickening with areas of loculated ascites
Diagnostic laparoscopy
(i) Multiple white plaques throughout peritoneum and omentum | (i) Caseating suppurative granulomas with giant cells with multinucleated thick-walled spherules containing endospores and stain positive for PAS and GMS
(ii) Coccidioides spp. can be distinguished from H. capsulatum and Cryptococcus spp. on the basis of variation in the size of the endospore and growing spherule as well as lack of narrow-based budding |
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| Basidiobolomycosis | Intestines and rectum (80%) and liver (20%) | Endoscopy
(i) Superficial ulcers within the cecum and ileocecal valve | (i) Deep biopsy required as the pathogen buries itself within the submucosa
(ii) Necrotizing granuloma with eosinophilic infiltration and Splendore-Hoeppli phenomenon (presence of amorphous, eosinophilic, and hyaline material surrounding the organism) |
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