Spontaneous transomental hernia: a case report of a rare internal hernia with a challenging diagnosis.

Introduction and Importance: Transomental hernia (TOH) is an extremely rare clinical condition that represents 1-4% of all internal hernias. Spontaneous TOH occurs in patients with no history of surgery or previous abdominal trauma. It happens after protrusion of the abdominal viscera, commonly the small bowel loops through a defect on the great omentum. Presentation of the case: We present a case of occlusion due to TOH in a 66-year-old man who underwent a laparotomy, and operative exploration showed 10 cm of small bowel incarcerated through a defect in the right side of the greater omentum of 4 cm in diameter. Discussion: The diagnosis is usually delayed because symptoms are nonspecific. Postoperative morbidity and mortality are important because patients present most frequently with gangrenous bowel, making morbidity and mortality higher. Therefore, it constitutes a critical surgical emergency and must be quickly recognized and managed. Computed tomography (CT) scan plays a prominent role in diagnosis. Midline laparotomy is the main emergency approach for patients with unknown bowel obstruction. Some authors suggest a laparoscopic approach, but it requires a surgeon's experience and propitious patient's conditions. Conclusion: TOH is the rarest type of internal hernia with extremely difficult preoperative diagnosis due to nonspecific semiology. This type of hernia has the highest morbidity and mortality rates of all internal hernias. Thus, it must be suspected whenever there is bowel obstruction of unknown origin and quickly managed.