This is an 83-year-old male patient with a large tubular adenoma occupying half of the circumference in the mid-rectum. The adenoma was classified as a laterally spreading tumor, specified as “nodular mixed,” with both nodular and also granular components. Histopathological findings from an external institute had already established a diagnosis of low-grade differentiated intraepithelial neoplasia. On endoscopic ultrasound and magnetic resonance imaging (MRI) of the pelvis before the intervention, neither infiltration of the muscularis propria nor any lymph-node enlargement was evident. In view of the patient’s age and comorbidities, it was decided to carry out an endoscopic piecemeal resection.

After detailed inspection and imaging of the findings, a solution of epinephrine and toluidine blue was injected under the lesion.

Endoscopic mucosal resection was then carried out. After the injected adenoma sections had been grasped using a monofilament snare, the superficial mucosal layers were resected piece by piece using high-frequency current. This was carried out from distal to proximal, in order to avoid creating separate islands of mucosa.

The process was repeated several times. Only the parts requiring ablation were selectively injected and then resected immediately afterward.

Small monofilament snares with a diameter of 15–25 mm were used. The advantages of these are that the injected sections are more easily grasped and the risk of perforation is lower than when larger snares are used.

The resected parts of the adenoma were then retrieved transanally for further histopathological processing.

Minor bleeding points were already coagulated during the resection procedure using the coagulation forceps. In addition, several clips were applied, allowing hemostasis of all macroscopically visible bleeding sources.

For parts of the adenoma that are difficult to access, it may be helpful to use a transparent distancing cap.

Snare-tip coagulation of the resection margin was carried out at the end, for prophylaxis against recurrences.
The adenoma was completely ablated. Histopathological analysis showed evidence of an early rectal carcinoma. In view of the patient’s age and comorbidities, it was decided in consultation with him to adopt a conservative approach based on best supportive care.