LAUSR

A counterclockwise intestinal rotation around superior mesenteric axis occurs progressively during the 5th to the 10th week of the organogenesis [2]. When this process stops prematurely after a rotation of only 90 degrees, the entire colon occupies the left half of the abdomen while the small intestine occupies the right side. This rare type of intestinal malrotation is known as “complete common mesentery” (CCM). It is widely accepted that colonic resections for cancer are conducted along the embryological planes to achieve a complete mesocolic excision improving oncological outcomes [1]. The fasciae delimiting the dissection planes, such as Toldt’s fascia, and Fredet’s fusion fascia originate from the coalescence processes of the primitive mesothelial surfaces. A 14-years-old young man was admitted to our institution for abdominal pain, nausea and vomiting. He had normal vital signs but physical examination revealed a tense and painful abdomen. Medical history included recurrent episodes of abdominal pain, especially after meals, and chronic constipation. Additionally, a previous MRI suggested a diagnosis of intestinal malrotation. Imaging described a 90 degrees counterclockwise rotation around the axis of the superior mesenteric artery as for CCM. After the exclusion of a total midgut volvulus, a laparoscopy was performed due to the failure of a non-operative treatment. Intraoperatively, dilation of the small bowel was observed and it was attributed to a specific adhesive syndrome involving intestinal loops. Lysis of the adhesions and a preventive appendectomy were performed. CCM is a rare congenital midgut disorder with characteristics of left-sided lying colon and right-sided lying small intestine as result of incomplete counterclockwise intestinal rotation (Fig. 1a–c). Toldt’s and Fredet’s fascia are well-known landmarks used by colorectal surgeons, and rotation of the digestive tract is a key step in embryological development of these “fusion fasciae”. Toldt’s fascia arises from the adhesion that occurs between the posterior layer of visceral peritoneum of the mesocolon and the parietal peritoneum. Similarly, Fredet’s fascia lies between the right mesocolon and the visceral duodenal-pancreatic peritoneum [3]. A sharp dissection in the embryological plane to remove an intact envelope of mesentery together with the corresponding lymphatic drainage is a key point of complete mesocolic excision [4]. Instead, dissection of Fredet’s fascia allows to identify submesocolic anterior face of the head of the pancreas and gastrocolic trunk of Henle during right colectomy [5]. In the present case, the duodenum surrounding the pancreatic head is not fixed in retroperitoneal position (Fig. 2a) and it is easily displaced to the left (Fig. 2b). Furthermore, duodeno-jejunal angle is abnormally located to the right of midline (Fig. 2c). Vena cava, right ureter and iliac vessels are easily detectable covered by the parietal posterior peritoneum, as well as an empty right iliac fossa (Fig. 3a, b). CCM is associated with the failure of normal embryologic rotation and fixation of the intestinal mesentery. As a postulate for colorectal surgeons, Toldt’s and Fredet’s fusion fasciae are missing in this condition. The knowledge of these anomalies has implications in surgical oncology for colon cancer and for the surgical access to the retroperitoneal anatomical structures when the intestinal malrotation occurs.