LAUSR

A 33-year-old woman was admitted to our unit with acute cramplike abdominal pain. Her symptoms began during the night and were associated with vomiting, non-specific abdominal tenderness, significant abdominal distension and loss of flatus. Her past medical history included chronic abdominal pain since childhood but no previous illness or surgery. The patient claimed that she had an identical monozygotic twin. Routine admission blood tests demonstrated an elevated white blood cell count and normal C-reactive protein. A diagnosis of acute intestinal obstruction was suspected. After intravenous fluid resuscitation, a contrast-enhanced computed tomography (CT) scan was performed, which revealed distension of the small intestine and ascending colon, in which a twist was identified as a sign of stricture. Thus, a volvulus was suspected, and the patient was taken to the operating room to undergo an emergency exploratory coelioscopy. The exploration showed rotation around the first third of the transverse colon of the small intestine and ascending colon (Fig. 1a) and detected an abnormal position of the duodenum, which failed to cross the midline behind the mesentery, with complete exposure of the pancreatic head (Fig. 1b). Conversion by midline laparotomy was then performed, confirming the diagnosis of a volvulus of the complete common mesentery due to fixation of the greater omentum along the left mesocolon. Then, the epiploic adhesions were divided, and after derotation and an appendicectomy, the small intestine was placed on the right side of the abdomen, whereas the caecum was returned to the left iliac fossa in a complete common mesentery position (Fig. 2). The post-operative period was uneventful, and the patient was discharged to her home on day 6 post-surgery. Her twin sister was screened for intestinal malrotation (IM) by CT, which was unexpectedly normal. IM is a congenital anomaly of midgut rotation during the fetal development. During the fifth intrauterine week, rapid elongation of the intestine results in herniation of the midgut through the umbilical cord. Simultaneously, the intestine rotates in an anticlockwise direction around the axis of the superior mesenteric artery, for a total of 270°. The process is completed during the 10th week, when the intestine returns to the abdominal cavity. The failures of rotation include rare cases of ‘non-rotation,’ cases of interrupted rotation in a 90° anticlockwise position (complete common mesentery position, in which the small bowel is on the right side of the abdomen and the caecum is on the left iliac fossa) or, most often, in a 180° anticlockwise position (incomplete common mesentery position, in which the caecum is close to the liver). The incomplete mesentery position is the position for which the risk of an intestinal volvulus is greatest due to the narrowness of the mesentery root. Thus, most cases of IM are diagnosed in the first month of life, and the incidence of IM in asymptomatic adults is reported to be extremely low. Surgical correction of an IM by Ladd’s procedure is preferred when an incomplete common mesentery is symptomatic, placing the bowels in a complete mesentery position after derotation and an appendicectomy. Our patient suffered from a volvulus of the midgut, whereas the mesentery was already in a complete common position. This condition is rarer than a volvulus of the incomplete mesentery due to widening of the mesentery root. IM is believed to result from the deficiency of several genes that are necessary for fetal development. Familial cases of IM have been published; further, four cases of simultaneous occurrence of IM in identical twins have also been reported, suggesting an autosomal dominant or recessive inheritance pattern and a strong correlation of IM in monozygotic twins. In our case, the patient’s twin sister also benefitted from a CT, which did not reveal any signs of IM, although