Novel approach for definitive treatment of retained rectal mucosa in FAP following restorative proctolectomy using transanal endoscopic surgery

Jingjing L Sherman, MD, Patricia Sylla, MD. Icahn School of Medicine at Mount Sinai

Patient is a 55 year old male with who underwent open restorative proctocolectomy, IPAA hand-sewn anastomosis and mucosectomy in 1996.  He presents with retain mucosal below the IPAA anastomosis and a posterior tubulovillous adenoma with low grade dysplasia. Decision was made to attempt completion mucosectomy using endoscopic submucosal dissection using a transanal endoscopic surgery platform due to risk of damange to pouch in transabdominal approach.

The 7.5 cm long  Stortz TEO platform was used. Endoscopic dissection began at the dentate line. A hook with monopolar cautery is used to mark the dentate line circumferentially followed by submucosal dissection of the remaining mucosa and polyp.  Once the polyp has been dissected off of the sphincter muscle,  submucosal dissection is carried out circumfrentially to remove all the retained rectal mucosal. Pathology confirmed rectal mucosa and tubulovillous adenoma. At follow up, he complained of transient moderate  fecal incontinence which  subsequently resolved, and did not develop a  stricture on exam.

Retained rectal mucosa after RPC and IPAA can result in polyps which can lead to cancer. The current treatment for retained rectal mucosa in this setting include completion mucosectomy with transanal pouch advancement, which may require transabdominal mobilization of the pouch, which is associated with a substantial risk of pouch injury. Other options include pouch excision and endoscopic mucosal resection.

This is the first reported case of completion mucosectomy after RPC and IPAA for FAP using a transanal endoscopic platform. This approach allows for good visualization anatomy and facilitates endoscopic submucosal dissection, and may not require pouch advancement. It is a local transanal approach and avoids abdominal surgery, which may lead to damage to the pouch or loss of pouch. It is a good option for patient with prohibitive operative risk and preserves sphincter function.