Berkeley R. Hanson, MD
Anna K. Henisz, MD, PhD,
Department of Diagnostic Imaging and Therapeutics, University of
Connecticut Health Center, Farmington, CT, and Paul M. Silverman,
MD, M.D. Anderson Cancer Center, Houston, TX.
A 60-year-old woman with a history of ventral hernia repair
presented with a 1-month history of severe, colicky, periumbilical
pain, nausea, and vomiting. Physical examination revealed a soft
abdomen with periumbilical tenderness and guarding. Laboratory
evaluation was normal. Ultrasound (not shown), computed tomography
(CT) (Figure 1), and small-bowel barium study (Figure 2) were
performed and followed by laparoscopy.
Small-bowel lipoma causing intussusception
Ultrasound evaluation of the abdomen showed no evidence of
cholecystitis or ascites (not shown). A contrast-enhanced CT of the
abdomen and pelvis revealed a well-circumscribed 4-× 4-cm mass of
homogenous fatty attenuation within the lumen of the distal small
bowel. In the area of the mass, the bowel wall was abnormally
thickened and small mesenteric vessels were being pulled into the
bowel lumen by an invaginating loop of bowel consistent with a
small-bowel intussusception (Figure 1). A subsequent barium
small-bowel study showed a filling defect with a coiled-spring
appearance in the distal ileum (Figure 2).
Laparoscopic resection of the involved section of distal ileum
was performed. The gross pathologic specimen showed a submucosal
lipoma with superficial mucosal necrosis and intense submucosal
congestion consistent with intussusception (Figure 3).
Historically, lipomas were diagnosed due to small-bowel
obstruction, but with the current wide use of CT, especially for
evaluation of abdominal pain, CT features are now readily
Intussusception in adults is relatively rare, occurring in
<5% of all intussusceptions and causing approximately 1% of
More than 80% of cases in adults have a known cause, the most
common being neoplasm, malignant more common than benign, followed
by idiopathic, postoperative complications and adhesions, Meckel's
diverticulum, foreign body, inflammation, lymphoid hyperplasia, and
celiac disease. Neoplasms serving as the lead point of colonic
intussusception are more commonly malignant, while those causing
enteric intussusceptions are usually benign. Adult intussusceptions
can be ileocolic, colocolic, enteroenteric, or jejunogastric and
are without anatomic predilec-tion.
This case was diagnosed on CT examination and confirmed on a
small-bowel barium study. We were able to document intussusceptions
on both studies of the same patient. Moreover, the presence of a
large ulceration, which was obvious on the pathologic examination,
was not visible on either study. Although lipomas are a common
benign tumor of the small bowel, second only to leiomyomas, and
>50% arise in the ileum, they have rarely been reported as cases
Small-bowel lipomas are usually solitary but may be multiple.
Most small-bowel lipomas are submucosal and project into the lumen,
which can serve as a lead point for intussusceptions. On CT, a
lipoma can be identified as a smooth hypoattenuated mass of-50 to
Antegrade and retrograde barium studies of the small bowel and
colon, respectively, can be used to evaluate intussusceptions. In
both the small bowel and colon, an intussusception causing
incomplete obstruction is found as contrast material trapped
between the intussusceptum and intussuscipiens creating a
"coiled-spring" appearance. Complete obstruction causes a beak-like
appearance at the point of obstruction.
Intussusceptions can also be evaluated via ultrasonography,
although not typically as an initial study. In cross-section, the
alternating layers of mucosa, bowel wall, and mesenteric fat are
seen as alternating concentric rings of hyperechoic and hypoechoic
Intussusception is best revealed by CT, and its findings are
The CT features include a soft-tissue mass with a target-like
(cross-sectional images) or sausage-like (sagittal images)
appearance. The central area of the target lesion is typically
hypoattuenuated, representing invaginated mesenteric fat and
vasculature and the intussusceptum, and is surrounded by a
Other CT findings include trapped oral contrast material between
the intussusceptum and intussuscipiens and a thickened bowel wall
with intramural air if the vascular supply is compromised.
After diagnosis, surgery is required in symptomatic patients or
in those who develop related complications. At the time of surgery,
the area of intussusception and, if appropriate, the inciting mass
are removed. If a benign tumor, such as homogenously fatty mass, is
suspected at the time of surgery, a laparoscopic approach should be
considered, which is a less invasive procedure; therefore, the
patient has a quicker recovery.
The positive diagnosis of bowel lipoma before surgery will
indicate laparoscopic approach rather than a routine laparotomy.
This approach is less invasive, is better tolerated, and offers a
patient faster recovery.