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Mesenteric lipoma is an unusual entity that is most often found in adults between 40 and 60 years of age and rarely occurs in the first decade of life, with fewer than 50 pediatric cases reported in the literature. Lipomas are the most common soft-tissue tumors and are generally ignored if they do not cause aesthetic problems or any symptoms of their anatomical localization.¹

Lipomas can be single or multiple and superficially or deeply localized. In children, lipomas occasionally develop superficially or in the trunk. Deep lipomas can be localized in the thorax, mediastinum, thoracic wall, pleura, pelvis, retroperitoneum, and paratesticular area, but they rarely originate in the intestinal mesentery in children. Lipomas have an increased incidence in people with obesity, diabetes mellitus, elevated cholesterol level, familial tendency, trauma, radiation therapy, or chromosomal translocation.¹

In the mesentery, they can occur at the root or encroach on the lumen.^2- 3They usually allow the passage of intestinal contents and, therefore, do not cause obstructive symptoms. They can attain enormous size and may present as an abdominal mass, pain, distention, an intestinal obstruction, weight loss, or anorexia, or they can be totally incidental. The mechanism by which a mesenteric mass can cause a small-bowel obstruction has not been elucidated. We suggest that an intestinal obstruction can result from a volvulus due to the mass. Diagnosis of mesenteric lipoma is rarely made preoperatively. Roentgenographic examination may show a well-demarcated, radiolucent area with intestinal obstruction, whereas ultrasonography can identify a well-encapsulated, homogeneous, echogenic mass with good through-transmission ultrasound (although this technique is rarely used to look at the mesentery of the bowel) and will detect a lipoma like that in our patient as a homogeneous mass of uncertain origin and probably as an incidental finding. Imaging evaluation of mesenteric masses is best carried out with a computed tomographic scan; lipoma has the appearance of subcutaneous fat and arises from the peritoneal cavity rather than the adjacent solid organs.⁴Colored Doppler ultrasonography and angiography will show that the tumor is avascular.

In the differential diagnosis of mesenteric lipoma, lipoblastoma, lymphangioma and lymphangiolipoma, neuroblastoma, and lymphoma should all be considered.^1,5- 6The tumor in our patient was a homogeneous, solid mass with no lobulation, marked septation, or cystic organization. Mesenteric lipomas are rare but should be considered in the differential diagnosis of patients with a soft and painless abdominal mass. Other rare causes of intestinal obstruction, such as large, benign, mesenteric cystic teratomas, should also be considered in the differential diagnosis.

Proceeding to laparotomy, the finding of a large mass encroaching into the small bowel led us to resect the adjoining small bowel because no clear plane could be identified between the two. Enucleation by laparoscopy is possible in selected cases, especially if there is a clear plane between the mass and the bowel wall.

The recurrence rate of lipomas is less than 5% and is usually due to incomplete excision.³Nevertheless, resection remains the best and most recommended form of treatment owing to lipomas' small malignant potential and low recurrence rate.⁷

In conclusion, small-bowel obstruction secondary to a volvulus caused by a mesenteric lipoma is a rare condition. Clinical information and computed tomographic findings may help in making the correct diagnosis.

Correspondence:Mounir Kisra, 10 P 8, Hay Riad, Rabat, Morocco (mounirkisra@yahoo.fr).

Accepted for Publication:August 30, 2005.

Author Contributions:Study concept and design: Kisra, Ettayebi, El Azzouzi, and Benhammou. Acquisition of data: Kisra. Analysis and interpretation of data: Kisra. Drafting of the manuscript: Kisra. Critical revision of the manuscript for important intellectual content: Ettayebi, El Azzouzi, and Benhammou. Statistical analysis: Kisra. Obtained funding: Kisra. Administrative, technical, and material support: Kisra. Study supervision: Benhammou.