Table 3.

Comparison of imaging and microscopic findings together with regions of the gastrointestinal tract affected by parasitic causes of granulomatous disease.

Parasitic granulomatous etiologies	Location in the gastrointestinal tract	Imaging findings	Histological findings
Schistosomiasis	Small (S. japonicum) and large intestines (S. mansoni) and liver	Endoscopy (i) Early-stage: edematous mucosa with superficial ulcers and petechial hemorrhage most commonly seen in the right colon (ii) Advanced stage: thickened bowel wall with strictures and polyps mostly within the left colon. Presence of gray-yellow exudates on the bowel wall	(i) Regular biopsies will demonstrate Schistosome eggs. If not clearly evident and there is a high index of suspicion, then crush biopsies can be diagnostic (ii) Early-stage: Schistosoma ova within the lamina propria with infiltration of the submucosa with eosinophils and neutrophils (iii) Advance stage: calcified or ruptured ova within the granuloma with infiltration of macrophages, lymphocytes, and plasma cells within the submucosa
Anisakiasis	Stomach → small and large intestines	Endoscopy (i) Erythematous mucosa with superficial erosions and granulomas Ultrasound (i) Large ascites with eosinophilia within the ascitic fluid (ii) Dilation of the small intestine with localized edema of Kerckring fold	(i) Ulcerated mucosa with granulomas along with evidence of Anisakis within the muscular layer surrounded by histiocytes and eosinophils (ii) Larvae will appear as thick multilayered cuticles with muscle fibers of polymyarial type in each quadrant of the worm and evidence of lateral chords with a characteristic butterfly-like appearance
Leishmaniasis	Esophagus, stomach, and small intestine	Endoscopy (i) Atrophy of the duodenal mucosa	(i) A granulomatous lesion with neutrophils and histiocytes with infiltration of Leishman-Donovan bodies