A Rare Cause of Childhood Ileus : Giant Mesenteric Lipoma and a Review of the Literature

Mesenteric lipomas are benign tumors of mature fat cells. They are usually asymptomatic and create a clinical picture that depends on the localization and size of the lipoma. Although rare, unusually large mesenteric giant lipomas can cause partial or complete bowel obstruction. Lipomas resulting in partial bowel obstruction can present with symptoms such as intermittent abdominal pain and abdominal distention. With complete obstruction, a child can present with an acute abdomen. Treatment is the excision of the mass along with the affected portion of bowel. In this case study, a 2-year-old female presented with a bowel obstruction due to the presence of a giant mesenteric lipoma. Clinical features of 16 cases published in the English literature to date are presented.


Introduction
Lipomas presenting in childhood can be superficial or deep.Deep-seated lipomas can originate from the thorax, chest wall, mediastinum, pleura, pelvis, retroperitoneum, paratesticular area and, very rarely, the bowel mesentery [1][2][3][4].As long as the bowel allows passage, mesenteric lipomas often do not cause gastrointestinal symptoms [5,6].However, a few can cause symptoms consistent with a partial bowel obstruction, such as intermittent abdominal pain, abdominal distention, and vomiting, with very few resulting in intestinal volvulus or complete intestinal obstruction due to torsion [4,7,8].These are usually reported as sporadic cases in the literature [2,4,5].To date, less than 50 cases of mesenteric lipoma have been reported in the Englishlanguage literature, with nearly half of them occurring in children [6].We report a 2-year-old female who presented with symptoms of complete bowel obstruction and review the features of children with mesenteric lipomas that have been described to date in the English literature.

Case Report
A 2-year-old female presented to the emergency department with abdominal pain and bilious vomiting that began 24 hours prior to her arrival.The patient reportedly had previous intermittent abdominal pain that was not severe enough to require a hospital visit.Upon physical examination, the patient was moderately dehydrated and her pulse was 110 beats/minute.The epigastric area appeared moderately distended and a well-circumscribed, firm and mobile mass extending from the abdominal midline to the left upper quadrant was palpable.Bowel sounds were normal.Blood tests revealed a normal white blood cell count and normal amylase, urea, creatinine and electrolyte levels.Supine abdominal radiography showed the intestinal segments located in the upper abdomen to be dilated with air-fluid levels present.Upon ultrasonography (US), a very large heterogeneous and hypoechogenic mass appeared to fill the entire upper abdomen.The lesion appeared to be separated from the walls of the intestine towards the periphery.No marked area of calcification was observed.During laparotomy, a light yellow mass filling the entire upper part of the abdomen was discovered.Intestinal obstruction developed due to the pressure of a semi-solid mass measuring approximately 15x20 cm and originating from the mesentery 90 cm proximal to the ileocecal valve.Circular necrosis developed in the region of the Ileum where the obstruction was present.This area was filled with subserosal feces (Figure 1).After excision of the mass and the resection of a segment of the affected intestine measuring approximately 20 cm (Figure 2), intestinal integrity was maintained with an end-to-end anastomosis.The patient had an uneventful postoperative course and was discharged on the 5th postoperative day.Upon macroscopic examination, the mass was found to measure 16x15x8 cm and weighed 770 g, which included the small segment of intestine surrounding the mass (Figure 3a).A histopathologic examination revealed that the tumor was composed of mature adipose tissue adjacent to the muscularis externa of the small intestine (Figure 3b).There was no evidence of mitotic changes with nuclear atypia, myxoid, degeneration, or multinucleated giant cells.The tumor borders were very smooth and there was no evidence of the invasion of the wall of the small intestine.

Discussion
The bowel mesentery is a rare location for deep-seated lipomas.Lipomas are usually slow-growing, non-lobulated, soft and mobile masses that do not penetrate into surrounding organs [4].The clinical picture of mesenteric lipomas usually presents as a partial obstruction due to compression or, rarely, a complete obstruction caused by intestinal volvulus [7][8][9].The most common intestinal symptoms in these cases are anorexia, abdominal distention, weight loss, constipation, and a feeling of fullness that increases after meals.When the tumor is close to the intestinal lumen and distant from the mesenteric root, its pressure on the bowel loops causes intermittent abdominal pain but allows for a partial intestinal passage.Our patient had a history of intermittent abdominal pain as well, but the pain had never been severe enough to require admittance to a hospital.However, the frequency of symptoms increased over the last month, with the addition of vomiting and abdominal swelling.
Many cases with a lipoma are detected incidentally, and symptoms may vary when the tumor becomes very large.The true prevalence of mesenteric lipoma within the population is not known, as there are most likely more cases with mild symptoms than cases that are actually published [6].Bass mentioned that, up until 1941, only 2 cases of children had been reported.Another case involving a 2-year-old was subsequently added to the literature, bringing the total number of cases to 3. Summers, in 1948, reviewed 128 cases with 16 types of solid mesenteric tumors in children that were in the same localization and stated that only one of them was a case of mesenteric lipoma [1].Subsequently, only sporadic pediatric cases in the form of case reports have been published.The characteristics of the 16 cases  that we found that have been published to date in the English literature are summarized in Table 1.
Although a definitive treatment for mesenteric lipomas has not been described, the complete resection of giant mesenteric lipomas with or without the removal of the affected bowel may be a treatment option when an intestinal obstruction or volvulus due to tumor compression is present.

Figure 1 .
Figure 1.General appearance of the mass and the structural change and obstruction of the small intestine due to mass compression.

Figure 2 .
Figure 2. The general appearance of the mass resected along with the affected part of the small intestine.