Case report

This is a 28-year-old male without any relevant medical history or family history who presented to the emergency department with rectal bleeding for the past few months. He had no other associated symptoms. Initial laboratory workup found a hemoglobin of 0.0033 g/dL and platelets of 17k.

Computed tomography angiography (CTA) of the abdomen and pelvis revealed intestinal nonrotation with left-sided colon, right-sided small bowel, and inversion of the superior mesenteric artery (SMA)/superior mesenteric vein (SMV) relationship (Figs 1 and 2).

Figure 1: CTA of the abdomen/pelvis showing the IMA, left colic artery, rectal artery, and sigmoid arteries.

Figure 2: CTA of the abdomen/pelvis with visualization of the SMA and its branches.

A flexible sigmoidoscopy was performed for evaluation of rectal bleeding. Diffuse polyposis beginning at the rectosigmoid junction was found, which was concerning for FAP. There was also a rectal polyp burden, which was deemed to be endoscopically clearable. After discussion with the patient regarding strict endoscopic surveillance versus surgical intervention, the patient was scheduled for laparoscopic total colectomy with ileorectal anastomosis.

Upon entering the abdomen, the entire small intestine was found in the right hemiabdomen, and the cecum was seen laying over the sacral promontory. The left colon was in the correct anatomical position with an intact white line of Toldt. The right colon was tethered to the small bowel mesentery and retroperitoneum rather than the right abdominal wall. Ladd’s bands connecting the transverse colon to the liver, duodenum, gallbladder, and stomach were also observed (Fig. 3).

Figure 3: Ladd’s bands tethering the transverse colon to the liver, duodenum, gallbladder, and stomach.

The transverse and left colon were mobilized first via lysis of Ladd’s bands. High ligation of the inferior mesenteric artery (IMA) was performed (Fig. 4). The mesentery to the origin of the middle colic vessels was then divided. The middle colon trunk was divided using the Ligasure device. Due to the abnormal anatomy, the inferior mesenteric vein was not visualized.

Figure 4: High ligation of the IMA.

The right colon was mobilized next. The ileocolic pedicle was identified, and the avascular plane underneath the vessel was entered, at which the SMV was seen inferiorly and preserved (Figs 5 and 6). High ligation of the ileocolic pedicle was performed. A pulse in the SMA and throughout the small intestine was confirmed. The terminal ileum was divided, and the upper rectum was mobilized. The ileorectal anastomosis was constructed using an end-to-end anastomosis stapling device via the rectum. Flexible endoscopy showed a healthy anastomosis with a negative leak test. The small bowel was evaluated after and appeared well perfused.

Figure 5: Ileocolic pedicle.

Figure 6: Avascular plane behind the ileocolic pedicle.

The patient’s postoperative recovery was complicated by an ileus and persistent thrombocytopenia**,** which was determined to be secondary to immune thrombocytopenia. The patient was discharged on postoperative day 12.

Pathology of the colon specimen found more than 100 tubular adenomas, some with foci of high-grade dysplasia. The distal colon margin was positive for low-grade dysplasia. The ileum was negative for dysplasia. The specimen overall was negative for carcinoma.