**3. When the rectum can be partially spare**

When the rectum can be partially spare, total abdominal colectomy with ileorectal anastomosis (TAC-IRA), a less complicated colorectal surgical procedure than RCP-IPAA, is an option. These solutions must be considered in attenuated familial adenomatous polyposis (aFAP) and synchronous colorectal cancer, and infrequently in UC and Crohn's disease.

The assessment of the rectum state is a parameter to consider when the surgical plan procedure is made. In FAP, behind the number of polyps present in the rectum (less than 10), the aggressiveness and development of extracolonic symptoms of the disease are other aspects to take into account. The mutation site on the APC gene is associated with the FAP phenotype, including desmoid tumor (DT) development. The more distal the mutation (closer to 3′ end), the higher the risk of the patient being affected by the desmoid tumor [1, 9, 17]. Typical disease symptoms were observed in families who harbored mutations between exon 4 (codon 169) and codon 1393 of exon 15. Mutations beyond codon 1403 were associated with a more varied phenotype concerning the development of extracolonic symptoms, namely desmoid tumor (DT). Their presence is related to aggressiveness disease and usually dictates the outcome of the patient. Despite the possibility of DT arising in any location, DT related to FAP is mostly on the abdominal region: intra-abdominal, on the abdominal wall, and transabdominal. Some of them take a benign course, with slow evolution, stabilization of growth, or even remission. Others show aggressive behavior with rapid growth and mass effect on surrounding structures, particularly in intra-abdominal DT. Possible complications of intra-abdominal DT are intestinal obstruction, ischemia, hemorrhage, and perforation or ureteric obstruction [1, 4, 8]. When DT develops in FAP patients, they can be the reason for the pouch failure case, and they are the second most common cause of mortality [20].

In synchronous CRC, the rectal tumor stage and location define the surgery to perform. If the rectum can be spare, TAC-AIR is the choice. RPC-IPAA with total mesorectum excision and with or without neoadjuvant chemoradiotherapy may be the solution in selected patients with medium or distal rectal cancer, depending on if the tumor is localized or locally advanced.

In IBD with proctocolitis involvement, rectum spare is controversial, mainly is ulcerative colitis. The decision-based in the absence of activity in the rectal mucosa.
