Understanding Gastrointestinal Subepithelial Lesions (SELs)

A gastrointestinal subepithelial lesion (SEL) is a mass or mass-like structure that protrudes into the gastrointestinal (GI) lumen, arising from layers beneath the mucosa of the GI tract wall. What to do when your doctor finds SELs?

These lesions can also result from external compression, sometimes mimicking SELs during endoscopic examinations. Previously termed "submucosal," the classification evolved with the introduction of endoscopic ultrasound (EUS), which enables precise differentiation of GI tract wall layers.

Types and Symptoms of SELs

SELs can be categorized as nonneoplastic, benign neoplastic, neoplastic with malignant potential, or outright malignant. Small SELs are often discovered incidentally and typically do not cause symptoms. However, larger SELs may lead to difficulties such as swallowing challenges, bleeding, or chronic anemia. Diagnosing SELs is complex because they originate beneath the mucosa, making simple mucosal biopsies inadequate. The use of EUS, complemented by EUS-guided sampling, significantly enhances diagnostic accuracy.

What is Endoscopic Ultrasound (EUS)?

Endoscopic Ultrasound (EUS) is a pivotal diagnostic procedure that integrates an endoscope with ultrasound technology to generate detailed images of the GI tract and adjacent organs. Here’s how it works:

• Using the Endoscope: A flexible tube equipped with a camera and ultrasound probe is gently inserted through the mouth or rectum.
• Capturing Images: Sound waves emitted by the ultrasound probe produce high-resolution images of internal structures.
• Identifying Issues: EUS effectively identifies tumors, cysts, stones, and other abnormalities within the digestive system.
• Facilitating Treatments: Beyond diagnostics, EUS facilitates therapeutic interventions such as cyst drainage or targeted injections for pain relief.

EUS plays a critical role in diagnosing conditions like cancer, pancreatitis, gallbladder disease, and SELs, guiding precise treatment strategies.

 

Key Concepts and Recommendations for SEL Management

1. Symptomatic SELs and Gastrointestinal Bleeding:
   • Surgical or endoscopic resection is recommended for symptomatic SELs or those causing gastrointestinal bleeding, irrespective of size. Exceptions include large gastrointestinal stromal tumors (GISTs), where tissue confirmation is necessary for planning neoadjuvant therapy.
2. Diagnosis with EUS:
   • EUS represents the gold standard for diagnosing SELs, particularly nonlipomatous (non-fatty tissue) tumors, surpassing traditional methods like standard endoscopy, CT scans, abdominal ultrasound, or MRI.
3. Contrast-Enhanced Imaging:
   • In cases where EUS is unavailable, contrast-enhanced imaging is recommended, with emphasis on referral to centers equipped with proficient endosonographers and advanced endoscopists.
4. Tissue Acquisition:
   • EUS-guided tissue acquisition is advocated to enhance diagnostic precision, especially for solid nonlipomatous SELs.
5. Surveillance and Treatment:
   • Patients lacking definitive tissue diagnosis or not undergoing resection should enroll in surveillance programs, except where benign nature is confidently established.
6. Management of Small SELs:
   • Approach to small SELs should be individualized based on location, accessibility for sampling, patient history, and risk-benefit analysis of surveillance versus primary endoscopic resection.
7. Treatment Recommendations:
   • Techniques such as Submucosal Tunneling Endoscopic Resection (STER), full-thickness resection though full-thickness resection device, or surgical excision are recommended for SELs involving the muscularis propria layer.
   • Surgical resection is advised for gastric GISTs larger than 2 cm and all non-gastric GISTs due to their malignant potential.
   • Endoscopic Mucosal Resection (EMR) and Endoscopic Submucosal Dissection (ESD) are suitable for managing type 1 gastric neuroendocrine tumors (gNETs).
8. Special Considerations:
   • ESD is preferred for low-grade, small type 3 gNETs without lymph node involvement.
   • For small, low-grade rectal neuroendocrine tumors, specific endoscopic therapies may not be recommended.

Importance of Expert Multidisciplinary Teams

Achieving optimal outcomes for SEL management necessitates treatment in large, high-volume medical centers equipped with multidisciplinary teams. These teams typically include specialists proficient in advanced endoscopy, radiology, oncology, surgical oncology, and gastrointestinal pathology, ensuring comprehensive care and accurate diagnosis.

Conclusion

When faced with a diagnosis of gastrointestinal subepithelial lesions, seeking care at a well-equipped medical institution with specialized expertise guarantees superior treatment outcomes. Advanced diagnostic tools like endoscopic ultrasound and state-of-the-art surgical techniques enable precise diagnosis and effective management, underscoring the importance of selecting a facility with advanced capabilities and multidisciplinary teams.



 
Tossapol Kerdsirichairat, MD, FASGE
Clinical Associate Professor of Medicine
Advanced/Bariatric Endoscopy, Digestive Disease Center
Bumrungrad International Hospital