RESUMEN
BACKGROUND Internal hernias are a rare cause of small bowel obstruction in patients, which usually have a long history of mild abdominal symptoms, sometimes leading to emergency surgery due to acute abdominal pain. Occasionally, it takes a long time to make the correct diagnosis because of symptoms vagueness and transience of typical imaging findings; at times, a definitive diagnosis is possible only through surgery, especially in cases of acute presentations in a low-resource setting where high-performance diagnostic equipment may be unavailable. CASE REPORT We report the case of a young male patient with a long history of mild abdominal symptoms and some episodes of acute abdominal pain. Following one of these episodes, several diagnostic examinations were performed and he was diagnosed with left paraduodenal hernia after typical signs were found on imaging exams, both CT and MRI; the patient underwent laparotomy with reduction of intestinal loops in the peritoneal cavity and suturing of the sac and was eventually discharged with no further symptoms whatsoever. CONCLUSIONS Among internal hernias, left paraduodenal hernias account for the major part and are characterized by the protrusion of bowel loops through the fossa of Landzert; herniated loops produce a sac-like appearance (typical imaging sign on both CT and MRI) and may cause partial displacement of other organs and blood vessels. Internal hernias should always be considered as a rare differential diagnosis in the workup of a patient with abdominal pain or intestinal obstruction: knowledge of both typical imaging features and specific surgical techniques are mandatory so that these patients may be properly cared for.