Gastric Crohn’s disease presenting as a subepithelial tumor: A case report

Table 1 Immunohistochemistryguided differential diagnosis of a gastric subepithelial lesion in the presented case

Entity	Prototypical IHC profile	Findings in the presented case	Interpretation
GIST	KIT (CD117)+, DOG1+, often CD34+	KIT (CD117)-, DOG1-, CD34-	Effectively rules out GIST
Gastrointestinal schwannoma	Diffuse S100+ (± SOX10+); CD34 usually negative	Focal S100 positivity; SOX10 staining not performed	Not supportive of schwannoma
IFP	CD34+; KIT (CD117)/DOG1-; may harbor PDGFRA mutation	CD34-	Argues against IFP
GCT	Diffuse S100+; SOX10+; CD68+ in tumor cells	Focal S100 positivity; CD68 highlights non-neoplastic histiocytes	Pattern not compatible with GCT
Leiomyoma	SMA+, desmin+, hcaldesmon+; KIT (CD117)/DOG1-	No features of a smooth muscle tumor; SMA/desmin staining not performed	Unlikely
LCH	CD1a+, Langerin (CD207)+, S100+	CD1a-; Langerin (CD207) staining not performed; focal S100 positivity	Rules out LCH
Upper gastrointestinal Crohn’s disease	Noncaseating granulomas; CD68+ histiocytes; typically CD1a-	Chronic active gastritis with ulceration and noncaseating granulomas; CD68+ histiocytes; CD1a-	Favored diagnosis

IHC: Immunohistochemistry; GIST: Gastrointestinal stromal tumor; IFP: Inflammatory fibroid polyp; GCT: Granular cell tumor; LCH: Langerhans cell histiocytosis.

Table 2 Clinical, endoscopic, and histopathological features and differential diagnoses of upper gastrointestinal involvement of Crohn’s disease

Category	Key features/findings
Clinical symptoms	Epigastric discomfort, epigastric pain, vomiting, dysphagia, weight loss, anorexia
Endoscopic findings	Aphthous ulcers, linear ulcers, cobblestone appearance of the mucosa, erosions, esophageal stricture, gastric outlet obstruction, duodenal stricture
Histopathological features	Noncaseating granulomas, chronic active inflammation, lymphoid follicular hyperplasia
Differential diagnoses	Esophagus-reflux esophagitis, eosinophilic esophagitis, viral esophagitis, tuberculous esophagitis, Stomach-Helicobacter pylori gastritis, NSAID-induced gastritis, tuberculous gastritis, Ménétrier’s disease, gastric lymphoma, Duodenum-peptic ulcer disease, celiac disease, tuberculous duodenitis, Brunner’s gland hyperplasia, duodenal lymphoma

NSAID: Nonsteroidal antiinflammatory drug.