What are the diagnostic steps and treatment options for a mass in the epigastric region?

Diagnostic Approach to an Epigastric Mass

For a mass in the epigastric region (below the sternum), proceed immediately with endoscopic ultrasonography (EUS) as the primary diagnostic modality, as it is the most accurate test for determining the layer of origin and echogenicity of the mass, which are critical for narrowing the differential diagnosis. 1

Initial Imaging Strategy

• Perform upper endoscopy first to visualize the mass and determine if it appears to be a subepithelial lesion versus an extrinsic compression. 1
• Standard forceps biopsy will likely be non-diagnostic for subepithelial masses, so do not rely on this alone. 1

When Cross-Sectional Imaging Shows Normal Structures

• If CT or MRI shows only normal structures but endoscopy reveals a "mass," you must perform EUS to confirm whether this represents external compression by a normal structure versus an intramural lesion that was missed on cross-sectional imaging. 1
• CT and MRI cannot reliably identify the histologic layers of the gut wall and are of limited value for distinguishing between different causes of intramural masses. 1

EUS Findings and Next Steps

For Hypoechoic Intramural Masses (Third or Fourth Layer)

Tissue sampling should be strongly considered for any hypoechoic mass in the third or fourth echo layer, as these have malignant potential including gastrointestinal stromal tumors (GISTs), carcinoid tumors, lymphomas, and metastases. 1

• Use EUS-guided fine-needle aspiration (FNA) with a 22-gauge needle for masses arising from the muscularis propria. 1
• Obtain 4-6 cores while varying the angle to ensure adequate sampling, targeting viable tumor tissue and avoiding necrotic areas. 2
• Apply immunocytochemistry (CD117/c-kit, CD34, smooth muscle actin, S100) to distinguish between GIST, leiomyoma, schwannoma, and other entities. 1

For Other EUS Patterns

• Hyperechoic, well-circumscribed submucosal masses are essentially diagnostic for lipomas and require no further evaluation. 1
• Anechoic structures with Doppler flow in the submucosa indicate varices—do not biopsy these. 1
• Anechoic, smooth, spherical structures with well-defined walls suggest duplication cysts. 1

Special Considerations for Esophagogastric Junction Masses

If the mass is located at or near the esophagogastric junction (EGJ):

• Determine the precise anatomic location using barium esophagography, esophagoscopy, and CT. 1
• Tumors with their midpoint in the lower thoracic esophagus, EGJ, or within the proximal 5 cm of the stomach that extend into the EGJ are staged as esophageal adenocarcinoma. 1
• Obtain tissue diagnosis specifying squamous cell carcinoma versus adenocarcinoma, tumor invasion depth, pathologic grade, and presence/absence of Barrett's esophagus. 1

Management Algorithm Based on Findings

Symptomatic Masses

Any patient with symptoms attributable to the mass (pain, bleeding, obstruction) should undergo endoscopic or surgical resection regardless of size or presumed histology. 1

Asymptomatic Masses

For incidentally detected asymptomatic masses, management options include: 1

• Resection (endoscopic for submucosal masses, surgical for muscularis propria masses ≥3 cm)
• Surveillance with periodic EUS (acceptable for small lesions with benign features, though one study showed 4% progression rate at 19 months) 1
• No further testing (only for clearly benign lesions like confirmed lipomas)

Size-Based Approach for GISTs

• GISTs ≥3 cm require surgical resection with local excision and clear margins (lymph node dissection not necessary). 1
• Small (<1 cm) hypoechoic masses remain controversial, but tissue sampling should be considered given malignant potential. 1

Critical Pitfalls to Avoid

• Do not proceed with definitive surgery for larger masses requiring complex resection without obtaining tissue diagnosis first, as this allows proper surgical planning and may avoid unnecessary surgery for non-surgical diseases like lymphoma. 2
• Do not rely on EUS imaging alone to determine malignant potential of individual GISTs—tissue diagnosis with immunohistochemistry is required. 1
• For suspected varices in patients with portal hypertension or splenic vein thrombosis, confirm with EUS and Doppler before any intervention to avoid catastrophic bleeding. 1
• Ensure tissue samples are fixed in formalin (never Bouin fixation) to preserve molecular analysis capability. 2