Is endoscopy necessary for a suspected small bowel mass?

Endoscopic Evaluation for Small Bowel Mass

For a suspected small bowel mass, endoscopy is necessary for definitive diagnosis, tissue sampling, and treatment planning, especially when cross-sectional imaging findings are inconclusive or when histological confirmation is required.

Diagnostic Algorithm for Small Bowel Mass

Initial Assessment

• For patients with suspected small bowel mass, the diagnostic approach should be determined based on presence of obstructive symptoms and risk of stenosis 1
• Cross-sectional imaging (MR enterography or CT enterography) should be the first-line method of choice in patients with obstructive features or known stenosis 1

Endoscopic Evaluation Options

Small Bowel Capsule Endoscopy (SBCE)

• SBCE may be the initial diagnostic modality for evaluation of small bowel in patients with suspected small bowel mass without obstructive symptoms or known stenosis 1
• SBCE has higher diagnostic yield for small bowel lesions compared to ileocolonoscopy, small bowel follow-through, and CT enterography 1
• SBCE is superior to MR enterography for detecting early mucosal lesions and proximal small bowel lesions 1
• A patency capsule should be used before performing SBCE if small bowel stenosis cannot be firmly excluded 1

Device-Assisted Enteroscopy

• Double balloon enteroscopy (DBE) or other device-assisted enteroscopy should be performed when tissue sampling or therapeutic intervention is required 1, 2
• DBE can detect small bowel mass lesions that may be missed by capsule endoscopy 2, 3
• Enteroscopy is complementary to SBCE and cross-sectional imaging when abnormalities are identified 1

Special Considerations

• The risk of capsule retention in patients without obstructive symptoms is low (approximately 1.5% in patients with suspected Crohn's disease) 1
• Small bowel masses may be missed by capsule endoscopy, particularly adenocarcinomas, which were missed in all cases in one study 2, 4
• Mucosal protrusion angle can help differentiate true submucosal masses from innocent bulges on SBCE (true masses have an average protrusion angle of 45.7° vs. 108.6° for bulges) 5

Clinical Pathway Based on Presentation

For Patients Without Obstructive Symptoms:

1. SBCE as initial diagnostic modality 1
2. If SBCE identifies a mass or suspicious lesion:
   • Follow with device-assisted enteroscopy for tissue sampling 1
   • Consider cross-sectional imaging for staging and extraluminal assessment 1
3. If SBCE shows only blood without identifying a lesion, consider device-assisted enteroscopy as masses may be missed by SBCE 2, 3

For Patients With Obstructive Symptoms or Known Stenosis:

1. Cross-sectional imaging (preferably MR enterography) as first-line investigation 1
2. Based on imaging results:
   • If mass identified: Consider device-assisted enteroscopy for tissue sampling 1
   • If imaging is inconclusive: Consider patency capsule followed by SBCE if patency is confirmed 1

Common Pitfalls to Avoid

• Relying solely on SBCE for definitive diagnosis of small bowel masses, as it has limitations in detecting certain types of tumors, particularly adenocarcinomas 2, 3
• Performing SBCE without assessing for potential obstruction, which can lead to capsule retention 1
• Failing to follow up non-specific SBCE findings (like fresh blood or erythema) with additional endoscopic evaluation 2, 4
• Not considering that higher diagnostic yield of SBCE may not correspond to higher diagnostic accuracy, as small lesions detected may not be specific for the underlying condition 1