Jin-Chun Cong, Chun-Sheng Chen, Lei Qiao, En-Qing Liu,
Department of General Surgery, The Second Hospital of China Medical
University, Shenyang 110004, Liaoning Province, China
Correspondence to: Dr Hong Zhang, Department of General
Surgery, The Second Hospital of China Medical University, Shenyang
110004, Liaoning Province, China.
Colon lipoma is remarkably rare in clinical practice. We
reported a case of ascending colon lipoma in an 83-year-old woman.
She was asymptomatic with a lipoma of 35 mm×30 mm×24 mm in size
which was found by routine colonoscopy. Right hemicolectomy was
performed uneventfully. The diagnosis was made by histological
examination. Reviewing the literature and combining with our
experience, we discussed the clinical features, diagnosis and
treatment of this uncommon disease.
© 2005 The WJG Press and Elsevier Inc. All rights reserved.
Key words: Colon lipoma; Case report; Review literature
Zhang H, Cong JC, Chen CS, Qiao L, Liu EQ. Submucous colon lipoma: A
case report and review of the literature. World J Gastroenterol
2005; 11(20): 3167-3169
Colon lipoma is generally mildly symptomatic or asymptomatic.
Even in the condition of presenting with dramatic characteristics in
colonoscopy, barium enema and CT scan, colon lipoma is still
underemphasized and misdiagnosed. We report a case of submucous
ascending colon lipoma and review the literature to evaluate the
clinical features, diagnosis and treatment of this disease.
An 83-year-old woman was admitted to the General Surgery Department
of our hospital on January 2003 for intermittent mild anal pain. She
denied any abdominal pain, constipation, diarrhea, hematochezia or
melena. She had a past medical history of cerebral infarction for at
least 10 years, and no cancer records were available. She received
appendectomy for acute appendicitis 9 years ago. No meaningful
findings were obtained in abdominal examination. Complete
evaluations of the ano-rectum were carried out which included visual
inspection, digital examination and anoscopy. The diagnosis of
external hemorrhoid was established and conservative treatment was
adopted. Detailed laboratorial studies showed all results within
normal limits, including complete peripheral blood cell counts,
blood biochemistry and carcinoembryonic antigen. Fecal occult blood
test was negative thrice consecutively. Colonoscopy was performed
afterward, and a yellowish hemispherical tumor of 45 mm in diameter
was detected at the site of ascending colon. The overlying mucosa
was smooth, and the lesion was soft and compressible (Figure 1A).
According to these features, the diagnosis of submucous tumor (SMT)
was made by colonoscopy. Biopsy showed non-specific colitis. Barium
enema revealed an ovoid filling defect with smooth border at the
proximal area of colon hepatic flexure (Figure 1B). Abdominal CT
scan found a pedunculated neoplasm protruding into the lumen of
ascending colon with sharp margin and soft tissue density (Figure
1C). Lipoma was considered to be the most probable cause, but
malignancy could not be excluded. Finally, the patient underwent
laparotomy, although she was asymptomatic and the tumor showed
benign features. Right hemicolectomy was performed uneventfully.
Surgery certified the diagnosis of colon lipoma. Macroscopic
inspection of the resected colon segment showed a smooth round
polypoid submucous tumor with elastic character and 35 mm×30 mm×24
mm in size (Figure 2A). Fault of the specimen demonstrated the tumor
with pedunculated appearance. The base of the lesion was 8 mm in
size. The tumor was covered by normal mucosa and had uniform
parenchyma in bright yellow color (Figure 2B). Histological
examination revealed characteristic lipoma of colon (Figure 3).
Figure 1 A:
The preoperative examination: Colonoscopy showed a yellowish
hemispherical tumor at the site of ascending colon. The overlying
mucosa was smooth, and the lesion was soft and compressible; B:
The preoperative examination: Barium enema revealed an ovoid filling
defect with smooth border at the proximal area of colon hepatic
The preoperative examination: CT scan found a pedunculated neoplasm
protruding into the lumen at the site of ascending colon with sharp
margin and soft tissue density.
Figure 2 A:
The macroscopic inspection: Macroscopic inspection of the resected
colon segment showed a smooth round polypoid submucous tumor with
elastic character and 35 mm×30 mm×24 mm in size; B:
The macroscopic inspection: Fault of the specimen demonstrated the
tumor with pedunculated appearance. The base of the lesion was 8 mm
in size. The tumor was covered by normal mucosa and had uniform
parenchyma in bright yellow color (one scale mark = 1 mm).
histological examination: Histological examination showed
characteristic lipoma of colon. No evidence of malignancy was
detected (hematoxylin and eosin, original magnification ×40).
Colon lipoma was described initially by Bauer in 1757. The incidence
was estimated to be about 0.26%
10 years ago, however the available data was kept insufficient
during the recent decade. Rogy et al.,
reported that colon lipoma constituted 0.3% of the cases treated for
colorectal diseases and 1.8% of the cases of benign colorectal tumor
during the same period. Elders are more likely to be involved, and
neither male nor female was found to be predominant according to
most of the current literatures, but this conception was disagreed
by some authors who reported a higher incidence in women than in men[2,3].
Most of the lesions were located at the right side of large bowel,
accounting for nearly 90% of cases. The majority of colon lipomas
presented as single while only 10% of cases were multiple. The most
frequent type was submucous lipoma with sessile or pedunculate
appearance, the remainder as subserosal lipoma was less than 10%.
Generally, colon lipoma is mildly symptomatic or asymptomatic.
Sometimes it was detected accidentally in examinations for other
purpose. Rogy et al.,
insisted that the clinical manifestations were associated with the
size of tumor and not related to the involved segment of large
bowel. As widely accepted, lipoma larger than 20 mm in diameter, is
likely to be symptomatic, it is quite unusual that the lipoma with a
maximum diameter of 35 mm is asymptomatic. The common symptoms of
colon lipomas include abnormal bowel habits, abdominal pain,
diarrhea, rectal bleeding, abdominal discomfort and melena.
Occasionally, patients may complain that a lump of hemorrhagic
tissues defecate from the rectum due to self-amputation of the
The episode of intussusception or intestinal obstruction can also be
seen in the patients with larger lipoma.
Even in some situations, abdominal emergency due to the
complications of colon lipoma was the first manifestation of these
patients. Sometimes colon lipoma can also be the source of massive
lower gastrointestinal bleeding.
Since no specific symptoms and physical signs are
available, accurate preoperative diagnosis is difficult to achieve.
Regarding the age and symptoms of these patients, malignant colon
tumors are often considered. With the development of colonoscopy,
barium enema and CT scan, some characteristic findings of colon
lipomas are useful in making diagnosis, even there is a case report
that colon lipoma was correctly diagnosed by sonography.
For the submucous lipoma, colonoscopy may directly visualize the
mass with tenting of the mucosa, which may be easily indented with a
closed biopsy forceps. As the forceps are withdrawn, the tumor will
soon spring back to resume its previous shape (pillow or cushion
pressure exerted on the lesion may compress the superficial vessels
and the distinctive yellow color of fat will disclose. Adipose
tissue may protrude through the biopsy site (naked fat sign) which
reveals fatty characteristic of the tumor.
But usually biopsy is not recommended in the patients with suspected
lipoma, because the lesion is beneath the normal mucosa and biopsy
often cannot promote diagnosis just as the result of non-specific
colitis in our case report, on the contrary, it increases the risks
of bleeding and perforation. According to the radiolucency of fatty
tissue, barium enema is helpful in making diagnosis by showing a
relatively radiolucent mass. Generally, lipoma appears as an ovoid,
well-demarcated filling defect. The characteristic of lipoma on
barium enema is so-called “squeeze-sign” which means that the
tumor can deform by external pressure or peristalsis. Computerized
tomography is considered to be the definitive diagnostic measure in
recognizing colon lipomas because the masses present characteristic
fatty densitometric values.
On CT scan image, lipoma has uniform appearance with fat-equivalent
density and smooth border. But for small lipoma, the diagnostic
value of CT is low.
Patients with small asymptomatic colon lipomas
need regular follow-up, and additional treatments are unnecessary.
Larger lipoma may cause symptoms, so resection should be considered
for those bigger than 20 mm in diameter.
Currently, the indication of endoscopic resection of colonic lipoma
is still a controversial subject. In our opinion, lipoma is
unreliable to endoscopic removal, partly because the fatty tissue is
inefficient conductor for electronic current and may result in a
significantly high rate of complication.
The risk of perforation or hemorrhage is notably increased when the
lesion is sessile or broadly-based. Surgical resection seems to be
the ideal choice of treatment, especially when the malignancy cannot
be completely excluded. Colotomy excision or segmental colon
resection is recommended for complete removal of the lipoma. If the
preoperative diagnosis of colon lipoma can be made correctly, extent
of surgery may be appropriately limited.
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Editor Ma JY and Guo SY Language Editor Elsevier HK