The clinical signs and symptoms of lesser sac hernia are non-specific and include abdominal pain, nausea, vomiting and distension. These rare lesser sac hernias can be lethal. Therefore, immediate diagnosis and surgery is essential. In the literature, only few cases of internal hernias have been documented . The anomaly of transmesocolic herniation, which was first reported by Rokitansky in 1836 is an extremely rare type of internal hernia . According to the literature, herniation into the lesser sac can be classified into three basic types according to the site of the aperture [7, 8]. Type 1 is a hernia through the foramen of Winslow, type 2 is a hernia through a defect in the lesser or greater omentum and type 3 is a hernia through a defect in the transverse mesocolon. Our patient had type 3 transmesocolic hernia. Type 3 is usually secondary to abdominal trauma or prior abdominal surgery with the creation of a Roux-en-Y loop [9, 10]. Approximately 5–10 % of all internal hernias occur through defects in the mesentery of the small bowel and almost 35 % of transmesocolic hernias are observed among paediatric age group, mainly those aged between 3 and 10 years . In adults, however most mesenteric defects are the result of previous gastrointestinal operations, abdominal trauma or intra peritoneal inflammation [11–13]. Our case was a rare presentation in an adult without a history of trauma or previous bowel surgery. Gomes et al.  and described a patient with congenital transmesenteric type internal hernia presented with intractable colick epigastric pain. Frediani et al.  has described a transmesocolic hernia presented with small intestinal obstruction. Agresta et al.  has described two patients presented with acute small intestinal obstruction due to internal hernia during immediate post operative period following laparoscopic hernia repair.
Although tansmesocolic hernia is a difficult preoperative diagnosis, CT abdomen might help the diagnosis by peripherally located small bowel, and lack of omental fat between the loops and the anterior abdominal wall [14, 15]. Congenital tansmesocolic hernias are extremely rare and todate only few cases of transmesocolic hernias were reported in the literature [3, 6, 16].
In conclusion, diagnosis of intestinal obstruction caused by a congenital mesocolic hernia remains difficult preoperatively despite the techniques currently available, so it is important to consider the possibility of a transmesocolic hernia in a patient with ileus even with no past history of gastrointestinal surgery.
Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.