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1205
Pictorial
Gastrointestinal Review Andrew
J. Taylor,1
Lipomas
on radiologic
warrant
Lipomas:
Edward
T. Stewart,
and
Wylie
A Radiologic
in the differential
diagnosis of mass lesions
of the gut In many instances, their morphologic characteristics allow the specific diagnosis of a lipoma. In this report, we review
gastrointestinal lipomas pathologic correlation.
General
an emphasis
with
on their radiologic
and
produced. Lesions larger than 2 cm may produce abdominal pain, intussusception, diarrhea, constipation, or gastrointestinal blood loss [1 , 2]. The gastrointestinal blood loss is usually chronic and can cause anemia [1]. Acute hemorrhage, however, can occur and usually is caused by ulceration of the overlying mucosa (Figs. 6C, 3E) or possibly intussusception (Figs. 1B, 3A).
Considerations
Lipomas of the gastrointestinal tract are uncommon, slow growing, fatty tumors that can occur anywhere along the gut. Although generally single, they may be multiple. Peak occurrence is in the fifth to seventh decade of life, with a slight female preponderance. The tumor itself is composed of welldifferentiated adipose tissue surrounded by a fibrous capsule. The cut surface is yellow and lobulated with a gross appearance of subcutaneous fat (Fig. 1 D). Approximately 90% to 95% of lipomas are located in the submucosa; the remaining 5% to 1 0% are subserosal [1]. Because of its usual position immediately superficial to the muscularis
and Pathologic
J. Dodds
of the gastrointestinal tract are an infrequent finding examination; however, they occur often enough to
consideration
Essay
propria,
underlying
muscular
contractions
tend
to
draw the tumor into the bowel lumen, forming an intraluminal polyp on a pseudopedicle (Figs. 2A, 3B, 4A). Lipomas usually are found incidentally during an examination done for another reason (Fig. 5). The size and location of the lipoma and the mobility afforded by the pseudopedicle, when present, account for the clinical signs and symptoms
Diagnosis Endoscopy Endoscopy and radiology play a major role in the diagnosis of lipomas. Endoscopy relies on the gross appearance of the mass to suggest the correct diagnosis. A smooth-surfaced mass that may vary from red-orange to yellow suggests the diagnosis of lipoma (Fig. 7C). Various maneuvers are used to confirm the diagnosis: (1) The “tenting” sign consists in grasping the mucosa with forceps and pulling or “tenting” it away from the underlying mass. (2) The “cushion” sign reflects the spongy nature of the mass when indented with a closed forceps. (3) The “naked fat” sign is produced when fat protrudes from the mass after multiple biopsies remove the overlying mucosa. A lipoma occasionally can be lobulated or have an apical ulceration (Fig. 3D). At times, ulceration can be fairly extensive, (Fig. 1 C), leading to the false impression of a more aggressive lesion.
May 21 , 1990; accepted after revision July 2, 1990. All authors: Department of Radiology, The Medical College of Wisconsin, Milwaukee, WI 53226. Address Radiology, Froedtert Memorial Lutheran Hospital, 9200 W. Wisconsin Ave., Milwaukee, WI 53226. Received I
AJR 155:1205-1210,
December
1990
0361 -803x/90/1 556-1 205 C
American
Roentgen Ray Society
reprint requests
to A. J. Taylor, Department
of
1206
TAYLOR
ET AL.
AJR:155,
December
1990
Fig. 1.-Small-bowel lipoma. A 39-year-old man had a 1-week history of increasing, intermittent, crampy epigastric pain. He had been followed up for 5 years because of a low hematocrit and guaiac-positive stools, thought to be a
resuft of “runner’s anemia.” A, On small-bowel
series,
a 3 x 4 cm polypoid of Treitz. At fiuoroscopy, there was intermittent intussusception. Note subtle Irregularity of mass, particularly at its apex (arrows). B, At surgery, intussusception of jejunum was found. Point of intussusception (curved arrow) is seen between dilated jejunum proximally (open
Downloaded from www.ajronline.org by 110.36.55.99 on 10/05/15 from IP address 110.36.55.99. Copyright ARRS. For personal use only; all rights reserved
mass was seen just distal to ligament
arrow) and normal caliber of jejunum just distally (straight solid arrow). C, Resected specimen larity of mucosal surface
shows marked irregudue to healing of over-
lying ulcerated and necrotic mucosa. D, Bivalved specimen chitecture of a lipoma.
shows
fatty internal
ar-
Fig. 2.-Esophageal lipoma. A 50-year-old woman had intermittent dysphagia. (Courtesy of J. Lammers, Brookfield, WI). A, Anteropostenor view from an esophago-
gram shows a large, smooth, mobile, pedunculated polyp in upper esophagus. B, Subsequent CT scan shows homogeneous internal
architecture
attenuation
of mass
(arrow)
with
similar to that of subcutaneous
an
fat.
These findings are diagnostic of a lipoma, which subsequently was proved by surgery. Lipoma had its origin just distal to cricoid cartilage.
Radiology Increased sophistication of radiologic studies now enables lipomas larger than 2 cm to be diagnosed with a high degree of accuracy [2]. The classic findings of a sharply marginated, smooth, ovoid or spherical mass with compressibility on fluoroscopic examination are supportive evidence of a lipoma (Figs. 7A and 7B). Other findings seen during studies follow directly from the gross appearance of lipoma wherein lobula-
tion and ulceration can be seen (Fig. 6A). However, with the use of a positive-contrast examination, it is only rarely possible to discern the relative low density of a mass when outlined by barium (Fig. 5). The imaginative water enema, developed to circumvent this problem (Fig. 8), has fallen from favor with the advent of newer imaging techniques. CT, in the properly prepared patient, is able to take advantage of the fat content, thereby identifying a mass as a lipoma. CT examination is now an appropriate first step for a definitive
GASTROINTESTINAL
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AJR:155, December1990
Fig. 3.-Colonic
lipoma.
A 67-year-old
woman
with 2-year
history
of vague
LIPOMAS
pain in right lower
1207
quadrant
had a recent
change
in bowel
habits.
having three to four loose stools each day and associated crampy pain and blood. A, Single-contrast barium enema shows a colonic intussusception with tip of intussusceptum (arrow) at tip of distal transverse colon. B, On reduction of intussusception during barium enema, a large mass with a wide stalk is seen originating from ileocecaI valve. C, CT scan shows mass (straight arrows) intussuscepted to distal transverse colon once again. Low attenuation value of mass is compatible Note central linear strand of higher attenuation material at base of mass (curved arrow). D, At colonoscopy, a large pinkish-orange mass capped with an ulcer (arrow) is seen. E, Surgical specimen shows a 6 x 5 x 4 cm mass with a broad-based pseudostalk and a large superficial fat protruding through ulcer.
Fig. 4.-Lipoma old woman
of sigmoid
had a 2-day
history
colon. A 36-yearof crampy
pain
in left lower quadrant. She recentiy had passed bright red blood per rectum. A, Anteroposterior view of sigmold colon
a single-contrast well-circumscribed
from
barium enema shows an oval, mass with a short, thick ped-
ide. B, Surgical specimen shows a lipoma superficial ulceration at apex (arrow).
with
She was
with fat.
ulcer at apex of mass (arrow). Note discolored
TAYLOR
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1208
ET AL.
AJR:155, December1990
Fig. 5.-Small incidental colonic lipoma. A 27year-old man had bright red blood per rectum. A, Anteroposterior coned-down view from a double-contrast barium enema shows sessile mass (arrows) in distal transverse colon. Mass was 1.0 x 2.5 cm, smooth and oval, with a very low density. B, A lateral view of same bowel segment shows mass in profile (arrows). Better visualized in this view is low density of mass, which is compatible with fat. Patient had endoscopy to locate source of bleeding: an anal fissure. Lipoma was not seen.
A
B
Fig. 6.-Gastric lipoma. blood. A, Upper gastrointestinal
An 83-year-old examination
woman shows
had
C a 2-week
a relatively
smooth
history gastric
of melena mass
and decreasing
(straight
solid
hematocrit,
arrows)
necessitating
with an ulcer (curved
transfusion arrow),
of 5 unIts
and a lobulation
of off
side of mass (open arrows). B, CT scan shows of mass.
C, At surgery,
a mass
mass (solid
(straight
arrows) of fatty internal architecture,
-50 HU, with a curvilinear
(curved
arrow) extending into fat from base
arrows) shows an ulcer (open arrow).
diagnosis of a lipoma. The finding of a homogeneous mass with Hounsfield units between -80 and -1 20 is nearly pa-
Location
thognomonic
Pharynx
for a lipoma
density
(Fig.
2B).
Heiken
et al. [2] reported
that lipomas seen on CT did not have nonfatty elements. However, in two of our cases (Figs. 3, 6), linear strands of soft-tissue attenuation were shown at the base of the lipomas (Figs. 3C, 6B). Both of these tumors had an associated ulcer. On pathologic examination, these strands seen on CT correlated with prominent fibrovascular septa, which are normally microscopic. These septa presumably enlarged from drainage of the inflammation associated with an ulcer. We therefore suggest that the presence of basilar strands of nonfatty elements in an otherwise uniform fatty tumefaction would qualify the lesion as a benign lipoma, probably containing an ulcer. This pattern should not be mistaken for a liposarcoma, which is extremely rare in the alimentary tract [2].
Within
Alimentary
Tract
and Esophagus
Lipomas may develop in the pharynx or in the esophagus, although these are the least common areas of involvement in the alimentary tract. Pharyngeal involvement is usually in the hypopharynx. The Iipoma commonly takes its origin from structures lying between and including the aryepiglottic folds to the pyriform sinuses [3]. Of the pedunculated pharyngeal polyps, the simple lipoma is relatively uncommon compared with the more frequent fibrolipoma [4]. The potential mobility of a hypopharyngeal lipoma and its location at the bifurcation of the aerodigestive tract accounts for the signs and symptoms of dysphagia, fullness in the throat, change in voice, sudden episodic attacks of dyspnea, and sleep apnea (Fig. 7)
GASTROINTESTINAL
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AJR:155, December1990
1209
LIPOMAS
Fig. 7.-Llpoma of hypopharynx. A 66-yearold man had an 18-month history of dysphagia and episodic paroxysms of cough. A, Oblique view from an esophagogram shows a smooth, pedunculated 7-cm mass that appears to emanate from hypopharynx. (Reprinted with permission from Olson et al (4].) B, Immediately after a swallow, mass elongates. In this case, intrinsic peristalsis of viscus shows complIance of mass. This phenomenon is referred to as “autopalpation.” (Reprinted with permission from Olson et aL (4].) C, Image from pharyngeal endoscopy shows a smooth pinkish-orange mass (straight solid arrows) In left pyriform sinus. (Open arrow = free edge of epiglottis, curved arrow = base of tongue). 0, Gross specimen shows mass has a pseudostalk.
Fig. 8.-Lipoma shown by water enema. A, Initial single-contrast barium enema shows a smooth mass (arrows) opposite ileocecal
valve. B, Subsequent enema with water shows mass (arrows) Is lucent compared with surrounding water. This finding is compatible with a lipoma, which subsequently was proved at surgery. (Barium-fllIed appendix projects over part of lipoma).
A
[4]. In some cases, the polyp may prolapse into the esophagus (Figs. 7A, 7B) and be mistaken for a mass of esophageal origin. Of benign esophageal tumors, the sessile leiomyoma is
B
most frequent; the fibrovascular polyp is the most common pedunculated esophageal polyp [4]. The lipoma is next in frequency, generally arising from the upper one third of the esophagus near the level of the cricoid cartilage (Fig. 2) [4].
TAYLOR
1210
ET AL.
AJR:155,
Fig.
9.-Multiple
mas. A 50-year-old
gastric
December
1990
duodenal
lipo-
and
woman had a 4-month history
of epigastric pain, with recent onset tent vomiting. Single anteroposterior
an upper gastrointestinal
of intermitview from
series shows multiple
Downloaded from www.ajronline.org by 110.36.55.99 on 10/05/15 from IP address 110.36.55.99. Copyright ARRS. For personal use only; all rights reserved
smooth masses along greater curvature of stomach (long arrows). Mass lesions (short arrows) continue into duodenum. At surgery, mass le-
sions were found to be lipomas. (Reprinted with permission
from Deeths
Fig. 10.-Multiple
et al [6].)
colonic
lipomas.
An oblique
view from single-contrast barium enema shows two smooth, well-circumscribed masses (arrows) at splenic flexure. At surgery, these proved
9
to be lipomas.
10
Stomach Gastric lipomas are a rare lesion accounting for only 5% of alimentary tract lipomas and for only 3% of all benign gastric masses [5]. Most gastric lipomas are located in the antrum; the remainder are spread throughout the body and fundus (Fig. 6). The usual antral location accounts for a high frequency of prolapse into the pylorus. Because of the lipoma’s supple nature, however, complete obstruction of the gastric outlet seldom occurs. As in other segments ofthe gut, lipomas are usually single but may be multiple (Fig. 9).
side of the colon, and next most commonly in the sigmoid colon (Fig. 4). The true lipoma of the ileocecal valve should not be confused with the more frequent lipomatosis of the valve. In the former case, the fat is encapsulated, causing a well-defined mass emanating from the valve instead of the generalized enlargement seen with diffuse fatty infiltration. Most colonic lipomas are solitary, but occasionally they may be multiple (Fig. 1 0). A rare condition of colonic lipomatosis exists in which innumerable small fatty deposits are present [8].
REFERENCES
Small
Bowel
The small bowel ranks as the second most common location for lipomas of the gut. About 20-25% of lipomas occur here [7], most frequently in the ileum. Lipomas are found less frequently in the jejunum (Fig. 1) and duodenum (Fig. 9) [7]. The lipoma is the second most common benign tumor of the small bowel; the first is leiomyoma [7].
Colon The colon is the most frequently involved segment of the bowel, accounting for 65-75% of lipomas [7]. In fact, lipomas are the second (albeit a distant second) most common benign tumor of the colon, after the adenomatous polyp [1]. Lipomas are found most commonly in the cecum (Fig. 6) and the right
1 . Femandez MJ, Davis RP, Nora PF. Gastrointestinal lipomas. Arch Surg 1983:118:1081-1083 2. Heiken JP, Forde KA, Gold RP. Computed tomography as a definitive method for diagnosing gastrointestinal lipomas. Radiology 1982:142: 409-414
3. Som PM, Scherl MP, Rao vM, Biller HF. Rare presentations of ordinary lipomas of the head and neck: a review. AJNR 1986;7:657-664 4. Olson DL, Dodds WJ, Stewart ET, Helm JF, Duncavage JA. Pedunculated pharyngeal lipoma presenting as an esophageal polyp. Dysphagia 1987:2:113-116 5. Chu AG, Clifton JA. Gastric and review of the literature.
lipoma presenting Am J Gastroenterol
as peptic
ulcer: case report
1983:78:615-618 6. Deeths TM, Madden PN, Dodds WJ. Multiple lipomas of the stomach and duodenum. Dig Dis Sci 1975:20:771-774 7. Agha FP, Dent TL, Fiddian-Green RG, Braunstein AH, Nostrant U. Bleeding lipomas
of the upper
gastrointestinal
Surg 1985:51 :279-285 8. Yatto RP. Colonic lipomatosis.
tract:
Am J Gastroenterol
a diagnostic
challenge.
1982;77:436-437
Am
1205
Pictorial
Gastrointestinal Review Andrew
J. Taylor,1
Lipomas
on radiologic
warrant
Lipomas:
Edward
T. Stewart,
and
Wylie
A Radiologic
in the differential
diagnosis of mass lesions
of the gut In many instances, their morphologic characteristics allow the specific diagnosis of a lipoma. In this report, we review
gastrointestinal lipomas pathologic correlation.
General
an emphasis
with
on their radiologic
and
produced. Lesions larger than 2 cm may produce abdominal pain, intussusception, diarrhea, constipation, or gastrointestinal blood loss [1 , 2]. The gastrointestinal blood loss is usually chronic and can cause anemia [1]. Acute hemorrhage, however, can occur and usually is caused by ulceration of the overlying mucosa (Figs. 6C, 3E) or possibly intussusception (Figs. 1B, 3A).
Considerations
Lipomas of the gastrointestinal tract are uncommon, slow growing, fatty tumors that can occur anywhere along the gut. Although generally single, they may be multiple. Peak occurrence is in the fifth to seventh decade of life, with a slight female preponderance. The tumor itself is composed of welldifferentiated adipose tissue surrounded by a fibrous capsule. The cut surface is yellow and lobulated with a gross appearance of subcutaneous fat (Fig. 1 D). Approximately 90% to 95% of lipomas are located in the submucosa; the remaining 5% to 1 0% are subserosal [1]. Because of its usual position immediately superficial to the muscularis
and Pathologic
J. Dodds
of the gastrointestinal tract are an infrequent finding examination; however, they occur often enough to
consideration
Essay
propria,
underlying
muscular
contractions
tend
to
draw the tumor into the bowel lumen, forming an intraluminal polyp on a pseudopedicle (Figs. 2A, 3B, 4A). Lipomas usually are found incidentally during an examination done for another reason (Fig. 5). The size and location of the lipoma and the mobility afforded by the pseudopedicle, when present, account for the clinical signs and symptoms
Diagnosis Endoscopy Endoscopy and radiology play a major role in the diagnosis of lipomas. Endoscopy relies on the gross appearance of the mass to suggest the correct diagnosis. A smooth-surfaced mass that may vary from red-orange to yellow suggests the diagnosis of lipoma (Fig. 7C). Various maneuvers are used to confirm the diagnosis: (1) The “tenting” sign consists in grasping the mucosa with forceps and pulling or “tenting” it away from the underlying mass. (2) The “cushion” sign reflects the spongy nature of the mass when indented with a closed forceps. (3) The “naked fat” sign is produced when fat protrudes from the mass after multiple biopsies remove the overlying mucosa. A lipoma occasionally can be lobulated or have an apical ulceration (Fig. 3D). At times, ulceration can be fairly extensive, (Fig. 1 C), leading to the false impression of a more aggressive lesion.
May 21 , 1990; accepted after revision July 2, 1990. All authors: Department of Radiology, The Medical College of Wisconsin, Milwaukee, WI 53226. Address Radiology, Froedtert Memorial Lutheran Hospital, 9200 W. Wisconsin Ave., Milwaukee, WI 53226. Received I
AJR 155:1205-1210,
December
1990
0361 -803x/90/1 556-1 205 C
American
Roentgen Ray Society
reprint requests
to A. J. Taylor, Department
of
1206
TAYLOR
ET AL.
AJR:155,
December
1990
Fig. 1.-Small-bowel lipoma. A 39-year-old man had a 1-week history of increasing, intermittent, crampy epigastric pain. He had been followed up for 5 years because of a low hematocrit and guaiac-positive stools, thought to be a
resuft of “runner’s anemia.” A, On small-bowel
series,
a 3 x 4 cm polypoid of Treitz. At fiuoroscopy, there was intermittent intussusception. Note subtle Irregularity of mass, particularly at its apex (arrows). B, At surgery, intussusception of jejunum was found. Point of intussusception (curved arrow) is seen between dilated jejunum proximally (open
Downloaded from www.ajronline.org by 110.36.55.99 on 10/05/15 from IP address 110.36.55.99. Copyright ARRS. For personal use only; all rights reserved
mass was seen just distal to ligament
arrow) and normal caliber of jejunum just distally (straight solid arrow). C, Resected specimen larity of mucosal surface
shows marked irregudue to healing of over-
lying ulcerated and necrotic mucosa. D, Bivalved specimen chitecture of a lipoma.
shows
fatty internal
ar-
Fig. 2.-Esophageal lipoma. A 50-year-old woman had intermittent dysphagia. (Courtesy of J. Lammers, Brookfield, WI). A, Anteropostenor view from an esophago-
gram shows a large, smooth, mobile, pedunculated polyp in upper esophagus. B, Subsequent CT scan shows homogeneous internal
architecture
attenuation
of mass
(arrow)
with
similar to that of subcutaneous
an
fat.
These findings are diagnostic of a lipoma, which subsequently was proved by surgery. Lipoma had its origin just distal to cricoid cartilage.
Radiology Increased sophistication of radiologic studies now enables lipomas larger than 2 cm to be diagnosed with a high degree of accuracy [2]. The classic findings of a sharply marginated, smooth, ovoid or spherical mass with compressibility on fluoroscopic examination are supportive evidence of a lipoma (Figs. 7A and 7B). Other findings seen during studies follow directly from the gross appearance of lipoma wherein lobula-
tion and ulceration can be seen (Fig. 6A). However, with the use of a positive-contrast examination, it is only rarely possible to discern the relative low density of a mass when outlined by barium (Fig. 5). The imaginative water enema, developed to circumvent this problem (Fig. 8), has fallen from favor with the advent of newer imaging techniques. CT, in the properly prepared patient, is able to take advantage of the fat content, thereby identifying a mass as a lipoma. CT examination is now an appropriate first step for a definitive
GASTROINTESTINAL
Downloaded from www.ajronline.org by 110.36.55.99 on 10/05/15 from IP address 110.36.55.99. Copyright ARRS. For personal use only; all rights reserved
AJR:155, December1990
Fig. 3.-Colonic
lipoma.
A 67-year-old
woman
with 2-year
history
of vague
LIPOMAS
pain in right lower
1207
quadrant
had a recent
change
in bowel
habits.
having three to four loose stools each day and associated crampy pain and blood. A, Single-contrast barium enema shows a colonic intussusception with tip of intussusceptum (arrow) at tip of distal transverse colon. B, On reduction of intussusception during barium enema, a large mass with a wide stalk is seen originating from ileocecaI valve. C, CT scan shows mass (straight arrows) intussuscepted to distal transverse colon once again. Low attenuation value of mass is compatible Note central linear strand of higher attenuation material at base of mass (curved arrow). D, At colonoscopy, a large pinkish-orange mass capped with an ulcer (arrow) is seen. E, Surgical specimen shows a 6 x 5 x 4 cm mass with a broad-based pseudostalk and a large superficial fat protruding through ulcer.
Fig. 4.-Lipoma old woman
of sigmoid
had a 2-day
history
colon. A 36-yearof crampy
pain
in left lower quadrant. She recentiy had passed bright red blood per rectum. A, Anteroposterior view of sigmold colon
a single-contrast well-circumscribed
from
barium enema shows an oval, mass with a short, thick ped-
ide. B, Surgical specimen shows a lipoma superficial ulceration at apex (arrow).
with
She was
with fat.
ulcer at apex of mass (arrow). Note discolored
TAYLOR
Downloaded from www.ajronline.org by 110.36.55.99 on 10/05/15 from IP address 110.36.55.99. Copyright ARRS. For personal use only; all rights reserved
1208
ET AL.
AJR:155, December1990
Fig. 5.-Small incidental colonic lipoma. A 27year-old man had bright red blood per rectum. A, Anteroposterior coned-down view from a double-contrast barium enema shows sessile mass (arrows) in distal transverse colon. Mass was 1.0 x 2.5 cm, smooth and oval, with a very low density. B, A lateral view of same bowel segment shows mass in profile (arrows). Better visualized in this view is low density of mass, which is compatible with fat. Patient had endoscopy to locate source of bleeding: an anal fissure. Lipoma was not seen.
A
B
Fig. 6.-Gastric lipoma. blood. A, Upper gastrointestinal
An 83-year-old examination
woman shows
had
C a 2-week
a relatively
smooth
history gastric
of melena mass
and decreasing
(straight
solid
hematocrit,
arrows)
necessitating
with an ulcer (curved
transfusion arrow),
of 5 unIts
and a lobulation
of off
side of mass (open arrows). B, CT scan shows of mass.
C, At surgery,
a mass
mass (solid
(straight
arrows) of fatty internal architecture,
-50 HU, with a curvilinear
(curved
arrow) extending into fat from base
arrows) shows an ulcer (open arrow).
diagnosis of a lipoma. The finding of a homogeneous mass with Hounsfield units between -80 and -1 20 is nearly pa-
Location
thognomonic
Pharynx
for a lipoma
density
(Fig.
2B).
Heiken
et al. [2] reported
that lipomas seen on CT did not have nonfatty elements. However, in two of our cases (Figs. 3, 6), linear strands of soft-tissue attenuation were shown at the base of the lipomas (Figs. 3C, 6B). Both of these tumors had an associated ulcer. On pathologic examination, these strands seen on CT correlated with prominent fibrovascular septa, which are normally microscopic. These septa presumably enlarged from drainage of the inflammation associated with an ulcer. We therefore suggest that the presence of basilar strands of nonfatty elements in an otherwise uniform fatty tumefaction would qualify the lesion as a benign lipoma, probably containing an ulcer. This pattern should not be mistaken for a liposarcoma, which is extremely rare in the alimentary tract [2].
Within
Alimentary
Tract
and Esophagus
Lipomas may develop in the pharynx or in the esophagus, although these are the least common areas of involvement in the alimentary tract. Pharyngeal involvement is usually in the hypopharynx. The Iipoma commonly takes its origin from structures lying between and including the aryepiglottic folds to the pyriform sinuses [3]. Of the pedunculated pharyngeal polyps, the simple lipoma is relatively uncommon compared with the more frequent fibrolipoma [4]. The potential mobility of a hypopharyngeal lipoma and its location at the bifurcation of the aerodigestive tract accounts for the signs and symptoms of dysphagia, fullness in the throat, change in voice, sudden episodic attacks of dyspnea, and sleep apnea (Fig. 7)
GASTROINTESTINAL
Downloaded from www.ajronline.org by 110.36.55.99 on 10/05/15 from IP address 110.36.55.99. Copyright ARRS. For personal use only; all rights reserved
AJR:155, December1990
1209
LIPOMAS
Fig. 7.-Llpoma of hypopharynx. A 66-yearold man had an 18-month history of dysphagia and episodic paroxysms of cough. A, Oblique view from an esophagogram shows a smooth, pedunculated 7-cm mass that appears to emanate from hypopharynx. (Reprinted with permission from Olson et al (4].) B, Immediately after a swallow, mass elongates. In this case, intrinsic peristalsis of viscus shows complIance of mass. This phenomenon is referred to as “autopalpation.” (Reprinted with permission from Olson et aL (4].) C, Image from pharyngeal endoscopy shows a smooth pinkish-orange mass (straight solid arrows) In left pyriform sinus. (Open arrow = free edge of epiglottis, curved arrow = base of tongue). 0, Gross specimen shows mass has a pseudostalk.
Fig. 8.-Lipoma shown by water enema. A, Initial single-contrast barium enema shows a smooth mass (arrows) opposite ileocecal
valve. B, Subsequent enema with water shows mass (arrows) Is lucent compared with surrounding water. This finding is compatible with a lipoma, which subsequently was proved at surgery. (Barium-fllIed appendix projects over part of lipoma).
A
[4]. In some cases, the polyp may prolapse into the esophagus (Figs. 7A, 7B) and be mistaken for a mass of esophageal origin. Of benign esophageal tumors, the sessile leiomyoma is
B
most frequent; the fibrovascular polyp is the most common pedunculated esophageal polyp [4]. The lipoma is next in frequency, generally arising from the upper one third of the esophagus near the level of the cricoid cartilage (Fig. 2) [4].
TAYLOR
1210
ET AL.
AJR:155,
Fig.
9.-Multiple
mas. A 50-year-old
gastric
December
1990
duodenal
lipo-
and
woman had a 4-month history
of epigastric pain, with recent onset tent vomiting. Single anteroposterior
an upper gastrointestinal
of intermitview from
series shows multiple
Downloaded from www.ajronline.org by 110.36.55.99 on 10/05/15 from IP address 110.36.55.99. Copyright ARRS. For personal use only; all rights reserved
smooth masses along greater curvature of stomach (long arrows). Mass lesions (short arrows) continue into duodenum. At surgery, mass le-
sions were found to be lipomas. (Reprinted with permission
from Deeths
Fig. 10.-Multiple
et al [6].)
colonic
lipomas.
An oblique
view from single-contrast barium enema shows two smooth, well-circumscribed masses (arrows) at splenic flexure. At surgery, these proved
9
to be lipomas.
10
Stomach Gastric lipomas are a rare lesion accounting for only 5% of alimentary tract lipomas and for only 3% of all benign gastric masses [5]. Most gastric lipomas are located in the antrum; the remainder are spread throughout the body and fundus (Fig. 6). The usual antral location accounts for a high frequency of prolapse into the pylorus. Because of the lipoma’s supple nature, however, complete obstruction of the gastric outlet seldom occurs. As in other segments ofthe gut, lipomas are usually single but may be multiple (Fig. 9).
side of the colon, and next most commonly in the sigmoid colon (Fig. 4). The true lipoma of the ileocecal valve should not be confused with the more frequent lipomatosis of the valve. In the former case, the fat is encapsulated, causing a well-defined mass emanating from the valve instead of the generalized enlargement seen with diffuse fatty infiltration. Most colonic lipomas are solitary, but occasionally they may be multiple (Fig. 1 0). A rare condition of colonic lipomatosis exists in which innumerable small fatty deposits are present [8].
REFERENCES
Small
Bowel
The small bowel ranks as the second most common location for lipomas of the gut. About 20-25% of lipomas occur here [7], most frequently in the ileum. Lipomas are found less frequently in the jejunum (Fig. 1) and duodenum (Fig. 9) [7]. The lipoma is the second most common benign tumor of the small bowel; the first is leiomyoma [7].
Colon The colon is the most frequently involved segment of the bowel, accounting for 65-75% of lipomas [7]. In fact, lipomas are the second (albeit a distant second) most common benign tumor of the colon, after the adenomatous polyp [1]. Lipomas are found most commonly in the cecum (Fig. 6) and the right
1 . Femandez MJ, Davis RP, Nora PF. Gastrointestinal lipomas. Arch Surg 1983:118:1081-1083 2. Heiken JP, Forde KA, Gold RP. Computed tomography as a definitive method for diagnosing gastrointestinal lipomas. Radiology 1982:142: 409-414
3. Som PM, Scherl MP, Rao vM, Biller HF. Rare presentations of ordinary lipomas of the head and neck: a review. AJNR 1986;7:657-664 4. Olson DL, Dodds WJ, Stewart ET, Helm JF, Duncavage JA. Pedunculated pharyngeal lipoma presenting as an esophageal polyp. Dysphagia 1987:2:113-116 5. Chu AG, Clifton JA. Gastric and review of the literature.
lipoma presenting Am J Gastroenterol
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1983:78:615-618 6. Deeths TM, Madden PN, Dodds WJ. Multiple lipomas of the stomach and duodenum. Dig Dis Sci 1975:20:771-774 7. Agha FP, Dent TL, Fiddian-Green RG, Braunstein AH, Nostrant U. Bleeding lipomas
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Surg 1985:51 :279-285 8. Yatto RP. Colonic lipomatosis.
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