Clinical History
Vague abdominal pain of recent onset, no symptoms of vomiting or diarrhea.
Imaging Findings
The patient presented to the outpatients department of Surgery with a vague abdominal pain of recent onset, had no symptoms of vomiting or diarrhea. Her medical history was only significant for essential arterial hypertension. No abnormalities were detected on physical examination or in standard laboratory testing.
She underwent a barium enema examination that showed the caecum, the trasversus and the ascending colon dislocated on the left while the small bowel occupied the right side of the abdomen. These abnormal positions revealed an intestinal malrotation of the midgut, a condition called “mesenterium commune”. The barium enema also showed some small diverticulum in the ascending and a bigger one in the sigmoid colon (fig.1).
An upper abdomen MRI was performed with axial and coronal TSE scans T2-weighted and FFE scans T1-weighted, and confirmed the intestinal malposition revealing the inverted relationship between the superior mesenteric artery (SMA)-the superior mesenteric vein (SMV) and the absence of the uncinate process of the pancreas (fig.2A-2B, 3).
Discussion
The 'mesenterium commune' is a rare congenital disorder that occurs as a defect of rotation of the midgut during embryologic development. Usually the diagnosis is obtained with conventional radiography (upper gastrointestinal barium and contrast enema examination) and cross-sectional imaging (CT and MRI) during the first months of life or during childhood due to a frequency of abdominal complaints and the life-threatening complications that occur. The clinical diagnosis of malrotation is difficult in adolescents and adults because the presentation is usually nonspecific with a history of episodic abdominal pain or vomiting [1,2], and consequently the suspicion is rarely considered. Seldom the malrotation remains asymptomatic.
During the 12th week of gestation the development of the midgut is characterized by rapid elongation of the gut and its mesentery, resulting in formation of the primitive intestinal loop that rotates counterclockwise around an axis formed by the superior mesenteric artery. As a result of rapid growth and expansion of the liver, the abdominal cavity temporarily becomes too small to contain the entire intestine and the primitive loop herniates out into the umbilical cord. As it does this, it rotates 90° about its axis. Then the loop is pulled back into the abdominal cavity and the loop rotates 180° again around the superior mesenteric artery. So the primary intestinal rotates a total of 270°.
Fundamentally there are two types of intestinal malrotation: in the first, which is more frequent, the rotation stops at 90° with the caecum and the colon localized in the left part of abdomen; in the second the primitive intestinal loop rotates 90° clockwise with the colon trasversus passing behind the duodenum and the superior mesenteric artery.
Both anomalies of rotation cause two life-threatening occlusive complications that result from the malfixation of the mesentery: the midgut volvulus and the internal hernia. In fact, normally, the large mesenteric attachment is shortened to a narrow pedicle that predisposes the patient to the complication of the midgut volvulus; the internal hernia results from the abnormal peritoneal fibrous bands (of Ladd) that attach to the right colon [3].
According to the epidemiological study of Mathias et al [4] the incidence of intestinal malrotation is 2.86 per 10000 live births and fetal deaths. This rate is higher than 0.4 per 10000 births reported by a study during 1982-86, and it indicates either an actual increase of the number of cases or an improvement in diagnosis of malrotation, particularly among asymptomatic cases.
In 94% of the cases there is an association with other structural birth defects regarding the development of the gastrointestinal tract such as diaphragmatic hernia, omphalocele, gastroschisis, oesophageal atresia and tracheo-oesophageal fistula. 5% of infants with malrotation may also have chromosomal abnormalities such as trisomy 21, trisomy 13, and trisomy 18.
Clinically the 'mesenterium commune' appears in the first month of life or in childhood, either with several abdominal complaints such as pain, vomiting, nausea, or with acute intestinal occlusion caused by midgut volvulus or strangulated internal hernia. Rarely the adults are totally asymptomatic; usually in their medical history there are long standing vague abdominal pains often associated with vomiting. Moreover in the asymptomatic cases there may be atypical clinical presentation of other disease, such as appendicitis with symptoms that are more left-sided. >br>
The diagnosis may be obtained with conventional radiography (upper gastrointestinal barium and contrast enema) even if they don’t have a high sensitivy and specificity for malrotation [3]. However the upper gastrointestinal contrast series show that the duodenal-jejunal junction fails to cross the midline and lies below the level of the duodenal bulb, on the right side of abdomen; this is a typical radiographic sign that, above all in the adults where the suspicion of malrotation is low, should not be dismissed as a normal variant . The contrast enema, such as in our case, usually shows the malposition of the caecum, ascending, and transversus dislocated in the left side of the abdomen. However the malposition of the caecum is non-specific because the caecal position may vary even without malrotation.
The CT and MRI represent the techniques with best diagnostic accuracy, and they allow the detection of many cases of quiescent malrotation in adults, or those with difficult interpretation at the conventional radiography. The CT and MRI allow to recognize not only the intestinal malposition seen on barium studies but also extraintestinal signs, such as a deviation from the normal relationship between the superior mesenteric artery (SMA) and superior mesenteric vein (SMV).The normal anatomical position of the SMV is on the right side of the SMA, in case of malrotation it is on the left side or on ventral position with respect to the SMA [5]. These finding can be seen on sonography with a US transverse section. However the abnormal orientation of SMA-SMV is not completely diagnostic because a vertical or inverted relationship may also be seen in patients without malrotation, and some cases of malrotation has a normal SMA-SMV orientation. Therefore, if this sign is accompanied with other findings it will confirm the diagnosis, otherwise it will be not sufficient for the diagnosis and other examination should be done. The underdevelopment of the pancreas and the absence of the uncinate process are two other findings associated with intestinal malrotation.
The diagnosis of asymptomatic or non-complicated mesenterium commune is very important for the above-mentioned life-threatening complications so that many authors advocate the surgical correction (Ladd’s procedure) for all the operative candidates found to have intestinal malrotation, regardless of age [1]. From this point of view the analysis carried out by Mazzinotti et al. shows that the laparoscopy could have an important role in the diagnosis, allowing the recognition of difficult cases to be detected on imaging, and in the treatment with the Ladd’s procedure. In this case due to the elderly age of the patient, and above all the absence of acute symptoms directly associated to intestinal malrotation, we did not think it opportune to carry out any surgical procedure.
Differential Diagnosis List
Asymptomatic intestinal malrotation
Final Diagnosis
Asymptomatic intestinal malrotation
