Endoscopic submucosal dissection for a giant circumferential early rectal cancer with massive schistosoma egg deposition: a case report.

Colorectal adenomatous polyps are well-established as the principal precancerous lesions underlying the adenoma-carcinoma sequence in colorectal carcinogenesis. The World Endoscopy Organization (WEO) consensus guidelines strongly advocate en bloc resection over piecemeal resection for laterally spreading lesions measuring >20 mm in diameter, given their elevated risk of superficial submucosal invasion. Nevertheless, achieving complete en bloc resection via endoscopic submucosal dissection (ESD) for circumferential lesions situated immediately adjacent to the anal verge and exceeding 10 cm in maximum dimension represents a formidable technical challenge. Herein, we report the successful en bloc ESD resection of a giant circumferential mixed-nodular laterally spreading lesion extending from the anal verge to 8 cm proximally, with postoperative histopathology confirming moderately differentiated adenocarcinoma (Figure 5). The patient presented with concomitant schistosomal colopathy, which further compounded the procedural complexity of ESD. Notwithstanding these challenges, meticulous perioperative assessment, refined surgical technique, and comprehensive postoperative management collectively demonstrate that ESD remains a safe and effective therapeutic modality for appropriately selected patients.