Discussion
Lipomas are the most common soft tissue tumours of adipocytes. They are
commonly located in proximal extremities and the trunk (1). Among all
small bowel lipomas, mesenteric location accounted for only 4.8% of all
cases (1).
It usually occurs in adults in the fourth to sixth decades of life (2).
They are rarer in children and young people as in the case of our
patient (1,3). There is an increased incidence of lipomas in patients
with obesity ,diabetes mellitus, hypercholesterolemia, genetic
predisposition and radiation therapy (3,4).However, our patient was thin
and none of these factors was found in.
Mesenteric lipomas have generally a slow growth without invasion of
surrounding organs (5). Besides, due to their soft consistency, most
patients are asymptomatic with a chance discovery during abdominal
laparotomy or CT scan done for other indications (1,6). The onset of
symptoms depends on the size, rapidity of growth, and location of the
tumor (1). An acute abdomen can reveal lipomas as they can lead to
intestinal obstruction or volvulus(1,5). Less frequently, they can be
revealed by chronic abdominal pain as in the case of our patient.
As the first-line investigation tool for abdominal pain due to its low
cost, ultrasound shows homogenous or heterogenous well-limited and
encapsulated intraperitoneal mass which may be confused with the
mesenteric fat (1,7). Computed tomography (CT) scan of the abdomen is
the gold standard imaging technique and plays a crucial role in the
diagnosis of mesenteric lipoma (1). It allows the analyse of the nature
and the density of the lesion, its exact location, its size and its
extent. It typically shows an intraperitoneal and encapsulated mass with
fatty attenuation with no lobulations, septations, or cystic
organization (1,8). Mesenteric lipomas are often located in the ileal
mesentery as in our case (1) .The first differential diagnosis to be
suspected are liposarcomas. They are heterogeneous and contain thick
septa with tumor extension to adjacent organs (9). Other rare
differential diagnoses should be suggested, in particular lipoblastoma,
cystic lymphangioma, lymphangiolipoma and neuroblastoma, but their
radiological aspects are different from those of lipomas (5).
Magnetic resonance imaging (MRI) is also very performant to describe in
detail the characteristics of the mass. She shows a hypointensity on
T1-weighted and T2-weighted images without modification of the signal
after injection of gadolinium (1). It confirms the fatty nature of the
tumor and differentiates giant lipomas from well-differentiated
liposarcomas (2). It prevents from doing invasive diagnostic techniques
such as biopsy before surgery (2).
Therapeutic management of mesenteric lipoma is not consensual and it is
based on the experience of the different teams. A small lipoma in a
asymptomatic patient can be left in place (1). In the absence of signs
of malignancy , complete surgical resection with, or if possible
without, the affected intestinal loop is the treatment of choice due to
the risk of intestinal obstruction by compression or volvulus (1,5).
Laparotomy was the most used management strategy often with resection of
the involved bowel followed by end-to-end anastomosis (1). Laparoscopy
may be indicated particularly in cases of small lipoma with a clear
plane of cleavage between the tumor and the adjacent small intestine,
thus allowing enucleation of the mass (2). In our case, CT scan showed a
typical benign mesenteric lipoma. Therefore, after an exploratory
laparotomy, we performed a complete resection of the mass while
conserving the intestine.
The recurrence rate of all lipomas after surgery is less than 5%, and
is usually due to incomplete excision (6).