Minimally Invasive Transanal Surgery (TAMIS) for a Giant Villous Adenoma of the Rectum: A Case Report

Introduction: Transanal minimally invasive surgery (TAMIS) is increasingly used for local excision of rectal lesions, especially when conventional endoscopy is not feasible. While its primary indications include benign and early malignant lesions, few reports exist on its use for large-volume rectal tumors. Case Presentation: We report a case of a 69-year-old male with a giant villous adenoma of the rectum showing focal areas of high-grade dysplasia. The patient underwent successful resection via TAMIS. The lesion measured approximately 11 cm in craniocaudal length and occupied two-thirds of the rectal circumference. Surgical time was 90 minutes, blood loss was minimal (50 mL), and hospital stay lasted 3 days. No intraoperative or postoperative complications occurred. Histopathology confirmed a tubular-villous adenoma with low-grade dysplasia and focal high-grade dysplasia, staged as pT1N0M0. No recurrence was observed at 6-month follow-up. Conclusion: TAMIS is a feasible, safe, and cost-effective approach for large rectal adenomas with early malignant transformation. It offers favorable perioperative outcomes, minimal morbidity, and short hospitalization when applied in appropriately selected patients.