Comparison of pCLE and EB in Gastric Lesion Diagnosis

This study compares two advanced endoscopic techniques — probe-based confocal laser endomicroscopy (pCLE, a microscopic real-time imaging tool) and endoscopic biopsy with a special dye (EB) — to see which more accurately determines the extent of early stomach cancer or precancerous lesions before minimally invasive removal surgery. **You may be eligible if...** - You are between 18 and 75 years old - You have been diagnosed with early stomach cancer or high- or low-grade stomach dysplasia (a precancerous condition) - You are scheduled for endoscopic submucosal dissection (ESD) surgery - Previous biopsy samples from your lesion are available for comparison **You may NOT be eligible if...** - You have advanced (not early-stage) stomach cancer or have had previous stomach removal surgery - You have severe heart or lung problems, liver cirrhosis, kidney dysfunction, or clotting disorders - You have an allergy to fluorescein dye - You are pregnant or breastfeeding - You have a psychiatric condition that prevents cooperation with endoscopy Talk to your doctor to see if this trial is right for you.