AJR:183, August 2004

415

Original Report

OBJECTIVE.

The purpose of this study was to describe the CT and radiographic featuresof gastrointestinal stromal tumors of the duodenum.

CONCLUSION.

Gastrointestinal stromal tumors of the duodenum appear on bariumstudies as extrinsically compressing or submucosal masses with or without ulceration. Thesetumors usually appear on contrast-enhanced CT as well-defined masses with an exoentericgrowth pattern and relatively good heterogeneous enhancement.

astrointestinal stromal tumors,formerly classified as leiomyo-mas or leiomyosarcomas, are

mesenchymal tumors of the gastrointestinaltract that differ from true leiomyomas andleiomyosarcomas [1]. Moreover, the nomen-clature, cell of origin, and pathologic sub-classification of this tumor have beendebated. The c-

kit

protooncogene proteinproduct CD117 was found immunohis-tochemically in gastrointestinal stromal tu-mors [2]. The recent availability of thetyrosine kinase inhibitor specific for

KIT,

STI-571 (Gleevec [imatinib mesylate], No-vartis) for successful treatment of malignantgastrointestinal stromal tumors mandates ahigh level of awareness of gastrointestinalstromal tumors [3].

Gastrointestinal stromal tumors most fre-quently occur in the stomach (60–70%) fol-lowed by the small intestine (20–30%),colorectum (10%), and esophagus (< 5%)[1]. Although the radiologic findings of gas-trointestinal stromal tumors have been de-scribed recently in the radiology literature[1, 4–6], the radiologic features of gas-trointestinal stromal tumors resemble thoseof leiomyomas or leiomyosarcomas, as hasalso been previously described [7, 8]. How-ever, to our knowledge, the radiology litera-

ture is limited regarding the imagingappearance of gastrointestinal stromal tu-mors of the duodenum, and no large seriesfocusing on gastrointestinal stromal tumorsof the duodenum has been reported. The pur-pose of our study was to describe the CT andradiographic findings of gastrointestinal stro-mal tumors of the duodenum.

Materials and Methods

From July 1998 to March 2003, 25 gastrointes-tinal stromal tumors of the duodenum were regis-tered at our institution’s pathology registry. Fivepatients were excluded because a CT scan was notavailable. Therefore, 20 patients were enrolled inthe study. Hard-copy CT scans were available fornine patients, and CT scan data were available on aPACS (Marotech) for the other 11 patients. Clinicaldata were reviewed for patient age and sex and thepresenting symptoms. The institutional reviewboard at our hospital did not require approval or in-formed patient consent for the review of medicalrecords and images.

CT examinations were performed using a Soma-tom Plus-4 (Siemens Medical Systems) or a HiSpeedAdvantage (GE Healthcare) scanner. Each patientreceived 120 mL of a nonionic contrast material (Ul-travist 370 [iopromide], Schering) through an 18-gauge angiographic catheter inserted into a forearmvein. The contrast material was injected at a rate of2.5 mL/sec using an automatic injector. Helical CT

Hyo-Cheol Kim

1

Jeong Min Lee

1

Kyu Ri Son

1

Se Hyung Kim

1

Kyoung Ho Lee

1

Kyoung Won Kim

2

Minjin Lee

3

Joon Koo Han

1

Byung Ihn Choi

1

Received November 27, 2003; accepted after revision January 21, 2004.

Supported in part by the 2003 BK21 Project for Medicine, Dentistry, and Pharmacy.

1

Department of Radiology, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center, and Clinical Research Institute, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea. Address correspondence to J. M. Lee (leejm@radcom.snu.ac.kr).

2

Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

3

Department of Pathology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea.

AJR

2004;183:415–419

0361–803X/04/1832–415

© American Roentgen Ray Society

G

Gastrointestinal Stromal Tumors of the Duodenum:

CT and Barium Study Findings

Dow

nloa

ded

from

ww

w.a

jron

line.

org

by U

nive

rsity

of

Vir

gini

a on

04/

16/1

3 fr

om I

P ad

dres

s 12

8.14

3.22

.132

. Cop

yrig

ht A

RR

S. F

or p

erso

nal u

se o

nly;

all

righ

ts r

eser

ved

416

AJR:183, August 2004

Kim et al.

was performed in each patient using the followingparameters: a 5- or 7-mm collimation, 1:1 tablepitch, and 5- or 7-mm reconstruction interval. Inseven patients, biphasic helical CT scans were ob-tained 30 (arterial phase) and 70 (portal venousphase) sec after the initiation of the contrast materialinjection. In 13 patients, monophasic helical CTscans were obtained with a 60- to 70-sec scanningdelay (portal venous phase). An upper gastrointesti-nal series was performed in 17 patients.

Two radiologists reviewed all the radiologic stud-ies retrospectively, and final interpretations werereached by consensus. Radiographic findings onbarium studies were reviewed to evaluate tumor lo-cation, ulceration, and morphologic characteristics.We reviewed only the CT scans that had been ob-tained during the portal venous phase for the tumorevaluation, whereas we assessed all the CT scans forthe metastasis evaluation. CT scans were reviewedto determine the size, shape, margin, and pattern anddegree of enhancement of the tumors; the presenceof ulceration and calcification within the lesions; andthe pattern of tumor growth (endoluminal, mixed, orexoenteric). Tumor margins were categorized aswell defined (a smooth or lobular contour withoutsurface projections), irregular (with surface projec-tions), or clearly invasive (when soft tissue of a simi-lar attenuation to that of the tumor penetrated anadjacent organ). An endoluminal growth pattern wasdefined to be present if the tumor mass attached tothe bowel wall was completely confined to thebowel lumen without bulging into the extraluminalspace. Conversely, an exoenteric growth pattern wasdefined to be present if the mass was confined to theextraluminal space without bulging into the bowellumen, although extrinsic indentation was observed.A mixed growth pattern was defined as a typicaldumbbell appearance. The degree of enhancement

was judged in comparison with that of muscle andliver: poor enhancement, identical to or less than thatof muscle; moderate enhancement, more than that ofmuscle but less than that of liver; and good enhance-ment, identical to or more than that of liver. CT find-ings were also evaluated for bowel obstruction, bileduct dilatation, abdominal lymphadenopathy, as-cites, and distant metastasis.

The pathology records of all patients were re-viewed to establish mitotic activity and tumor im-munoreactivity to CD117. On the basis of previousstudies on gastrointestinal stromal tumors [9],

thecriteria of benignity and malignancy were defined.The histopathologic findings in surgical specimenswere retrospectively reviewed by one gastrointesti-nal pathologist with an emphasis on the detectionof hemorrhage, necrosis, or cystic degeneration. Adirect comparison between imaging and histo-pathologic findings was performed by another pa-thologist, and two radiologists reviewed thepathology reports, photographs of gross specimens,and microscopic examinations.

Results

The study group comprised six men and 14women who ranged in age from 25 to 75 years(mean, 53 years). Nineteen patients presentedwith abdominal pain or discomfort (

n

= 8),melena (

n

= 5), symptoms of anemia causedby occult bleeding (

n

= 2), vomiting (

n

= 2),palpable abdominal mass (

n

= 1), or jaundice(

n

= 1). In the remaining patient, tumors wereincidentally detected during a periodic medicalcheckup. Seventeen patients underwent surgi-cal removal of the tumor, which includedWhipple operation (

n

= 3), pylorus-preserving

pancreaticoduodenectomy (

n

= 6), duodenalresection and anastomosis (

n

= 2), and duode-nal wedge resection (

n

= 6). Three patients un-derwent only a biopsy for liver metastasis.

On barium studies, eight of the 17 tumorshad ulceration. Six tumors, having ulceration(

n

= 3) or not (

n

= 3), appeared to besmoothly marginated mural-based massesthat formed obtuse angles with the duodenalwall and were compatible with submucosaltumor (Fig. 1). Eleven tumors appeared as anextrinsic compression with (

n

= 5) (Fig. 2) orwithout (

n

= 6) ulceration. On CT scans, tumors ranged from 2.5 to 13

cm in greatest dimension (mean, 7.2 cm) and13 tumors (65%) were larger than 5 cm. The20 gastrointestinal stromal tumors were lo-cated in the first (

n

= 1), second (

n

= 9), third(

n

= 8), or fourth (

n

= 2) portion of the duode-num. Seven tumors (35%) were smooth (Fig.3), whereas 13 tumors (65%) had a lobulatedcontour (Fig. 4). The tumor margin was welldefined in 16 tumors (80%), and two tumors(10%) had an irregular margin; the remainingtwo (10%) had invaded renal vessels

(Fig. 4)and the ascending colon, respectively. Six tu-mors (30%) had a mixed growth pattern, and14 tumors (70%) showed an exoenteric growthpattern. In five of six tumors showing a mixedgrowth pattern, the extraluminal portion com-prised most of the tumor volume. Two tumors(10%) showed a homogeneous enhancementpattern (Fig. 3), but 18 tumors (90%) showed aheterogeneous pattern. Seven tumors (35%)had good enhancement, 11 (55%) had moder-

A B

Fig. 1.—55-year-old woman with gastrointestinal stromal tumor of duodenum with low malignant potential.A, Barium study shows well-circumscribed mass (arrows) in first portion of duodenum.B, Contrast-enhanced CT scan shows well-defined mass (arrow) with peripheral high-attenuating rim and central areas of low attenuation between gallbladder and pancreas.

Dow

nloa

ded

from

ww

w.a

jron

line.

org

by U

nive

rsity

of

Vir

gini

a on

04/

16/1

3 fr

om I

P ad

dres

s 12

8.14

3.22

.132

. Cop

yrig

ht A

RR

S. F

or p

erso

nal u

se o

nly;

all

righ

ts r

eser

ved

Gastrointestinal Stromal Tumors of the Duodenum

AJR:183, August 2004

417

ate enhancement, and two (10%) had poor en-hancement. On CT, ulceration was observed insix patients and air–fluid level was observed inthree patients (Fig. 2B). Calcification was ob-served in one tumor.

No patients had lymphadenopathy or ascites.Duodenal obstruction was detected in one pa-tient. Liver metastases were present in five pa-tients. Metastatic lesions in the liver werehypoattenuating during the portal venous phasein four patients, and metastatic lesions wereisoattenuating during the portal venous phaseand hyperattenuating during the arterial phase inthe fifth patient (Fig. 5). The bile duct was di-

lated in four patients, and two patients under-went percutaneous transhepatic biliary drainagedue to hyperbilirubinemia before surgery.

Immunohistochemical studies showedCD117 expression in all patients. Of the 20 gas-trointestinal stromal tumors of the duodenum,five were classified as having low malignant po-tential and 15 as being malignant. Gross speci-mens of 14 tumors were available for review. Ofthe two tumors that showed homogeneous at-tenuation on CT, one was a solid tumor withouthemorrhage or necrosis at pathologic examina-tion and the other was a solid tumor containingmultiple punctate hemorrhages. In 12 tumors

with heterogeneous attenuation on CT scans,central areas of low attenuation were found tocorrespond to necrosis with hemorrhage (

n

=10), the solid tumor itself (

n

= 1), or fluid in anulcer (

n

= 1).

Discussion

Gastrointestinal stromal tumors of the duode-num account for 10–33% of all malignantduodenal tumors [10]. The sex distribution isapproximately equal. Most gastrointestinal stro-mal tumors of the duodenum are located in thesecond or third portion of the duodenum. How-

A B

Fig. 2.—45-year-old man with malignant gastrointestinal stromal tumor of duodenum. A, Barium study shows extrinsic compression on third portion of duodenum and focal collection of barium (arrow) in cavity. B, Contrast-enhanced CT scan shows cavitary mass lesion (arrows) with air–fluid level.

Fig. 3.—27-year-old woman with malignant gastrointestinal stromal tumor of duode-num. Contrast-enhanced CT scan shows well-enhancing round homogeneous mass(arrow) with intact overlying mucosa (arrowhead).

Fig. 4.—68-year-old woman with malignant gastrointestinal stromal tumor ofduodenum. Contrast-enhanced CT scan shows lobulated mass lesion encasingright renal vessels (straight arrow) and inferior vena cava (curved arrow). Notestomach is dilated as result of duodenal obstruction.

Dow

nloa

ded

from

ww

w.a

jron

line.

org

by U

nive

rsity

of

Vir

gini

a on

04/

16/1

3 fr

om I

P ad

dres

s 12

8.14

3.22

.132

. Cop

yrig

ht A

RR

S. F

or p

erso

nal u

se o

nly;

all

righ

ts r

eser

ved

418

AJR:183, August 2004

Kim et al.

ever, despite their large size, they rarely causeduodenal obstruction or obstructive jaundice.The common symptoms of gastrointestinal stro-mal tumors are hemorrhage, chronic anemia,palpable mass, weight loss, and abdominal pain[1]. In our study, these clinical findings, exceptequal sex distribution, concur with the literature.By chance, the five patients whose CT scanswere unavailable were men. Thus, if they hadbeen taken into account, there would have beenno sexual predominance in our sample.

A malignant gastrointestinal stromal tumorappears as a large well-circumscribed tumorthat is usually predominantly extraluminal andhas a heterogeneously enhancing soft-tissuerim surrounding a necrotic center [1, 4, 5]. Be-nign gastrointestinal stromal tumors are oftensmall round or ovoid tumors that are usuallyendoluminal and have a homogeneous enhanc-ing pattern [5, 7, 8]. Generally speaking, the

radiologic features of gastrointestinal stro-mal tumors of the duodenum seem to besimilar to those that occur in the remainderof the gastrointestinal tract. In our series,most gastrointestinal stromal tumors of theduodenum—even small ones—grew in an ex-traluminal direction and showed heteroge-neous attenuation on CT, whereas other smallgastric gastrointestinal stromal tumors have of-ten shown an endoluminal growth pattern andhomogeneous attenuation [8].

The liver is the most common metastaticsite at both presentation and disease relapse[4]. On CT scans obtained during the portalvenous phase, metastasis in the liver was usu-ally hypoattenuated compared with the normalsurrounding liver [4, 11]. In our series, one pa-tient had multiple small liver metastases thatwere isoattenuating on CT during the portalvenous phase and hyperattenuating during the

arterial phase. We may have missed some hy-pervascular liver metastases, because biphasicCT was undertaken in only seven of the 20 pa-tients. The availability of the tyrosine kinaseinhibitor has markedly altered the clinical ap-proach to gastrointestinal stromal tumor, andthis inhibitor has been proven effective in themanagement of metastatic gastrointestinalstromal tumor [3]. Therefore, the detection ofliver metastasis has become more importantthan ever. Additional studies may be needed todetermine whether biphasic helical CT can de-tect more liver metastases than monophasichelical CT in patients with gastrointestinalstromal tumors.

It may be difficult to determine the organ oforigin of a significant exoenteric tumor fromthe duodenum using cross-sectional imagingalone. For example, the differentiation of a tu-mor located between the duodenum and the

Fig. 5.—58-year-old man with gastrointestinal stromal tumor of duodenum with mul-tiple liver metastases.A, Contrast-enhanced CT scan shows well-defined heterogeneous mass lesion (ar-row) abutting duodenal wall. B, Contrast-enhanced CT scan obtained during arterial phase shows multiple smallhigh-attenuating lesions (arrows) in liver.C, Contrast-enhanced CT scan obtained during portal venous phase shows no focallesion in liver.

A B

C

Dow

nloa

ded

from

ww

w.a

jron

line.

org

by U

nive

rsity

of

Vir

gini

a on

04/

16/1

3 fr

om I

P ad

dres

s 12

8.14

3.22

.132

. Cop

yrig

ht A

RR

S. F

or p

erso

nal u

se o

nly;

all

righ

ts r

eser

ved

Gastrointestinal Stromal Tumors of the Duodenum

AJR:183, August 2004

419

pancreas may be difficult. A gastrointestinalstromal tumor of the duodenum appears as awell-defined mass with heterogeneous attenu-ation, whereas a pancreatic tumor commonlyappears as an ill-defined mass with poor en-hancement. However, a solid pseudopapillarytumor of the pancreas may have features resem-bling those of a gastrointestinal stromal tumorof the duodenum, such as a well-encapsulatedmass with hemorrhage [12]. An intact dis-placed pancreas head can be observed in pa-tients with a gastrointestinal stromal tumor ofthe duodenum, whereas the appearance of apancreas with a “beak” suggests a pancreaticorigin in patients with a solid pseudopapillarytumor of the pancreas. We also believe thatcentral gas and a cavitary mass militate againstthe diagnosis of a pancreatic tumor.

The differential diagnosis for gastrointesti-nal stromal tumors of the duodenum includesprimary and metastatic duodenal neoplasms.Adenocarcinoma is the most common primarymalignancy of the duodenum and typicallymanifests as an annular narrowing with abruptconcentric or irregular overhanging edges or asa polypoid tumor mass. Thus, its appearanceusually does not overlap with that of gas-trointestinal stromal tumors [13]. Lymphomasmay produce large ulcerative or cavitarymasses that may be indistinguishable fromgastrointestinal stromal tumors on radiologicimages. However, the presence of associatedlymphadenopathy favors a diagnosis of lym-

phoma. Carcinoid tumors may appear as ill-defined, homogeneous masses with displacedbowel loops. Paragangliomas are soft-tissue-attenuation masses with homogeneous en-hancement and appear as smoothly margineddumbbell-shaped masses [14] that could beconfused with gastrointestinal stromal tumorsof the duodenum.

In conclusion, gastrointestinal stromal tu-mors of the duodenum appear on barium stud-ies as extrinsically compressing or submucosalmasses with or without ulceration. The com-mon CT findings of gastrointestinal stromaltumors of the duodenum are well-definedexoenteric masses that usually consist of anirregular central area of low attenuation sur-rounded by variously thickened soft-tissue-density walls with or without ulceration.

References

1. Levy AD, Remotti HE, Thompson WM, SobinLH, Miettinen M. Gastrointestinal stromal tu-mors: radiologic features with pathologic correla-tion.

RadioGraphics

2003;23:283–3042. Hirota S, Isozaki K, Moriyama Y, et al. Gain-of-

function mutations of c-

kit

in human gastrointes-tinal stromal tumors.

Science

1998;279:577–580 3. Demetri GD, von Mehren M, Blanke CD, et al.

Efficacy and safety of imatinib mesylate in ad-vanced gastrointestinal stromal tumors.

N Engl JMed

2002;347:472–480 4. Burkill GJ, Badran M, Al-Muderis O, et al. Ma-

lignant gastrointestinal stromal tumor: distribu-

tion, imaging features, and pattern of metastaticspread.

Radiology

2003;226:527–5325. Ghanem N, Altehoefer C, Furtwangler A, et al.

Computed tomography in gastrointestinal stromaltumors.

Eur Radiol

2003;13:1669–16786. Levy AD, Remotti HE, Thompson WM, Sobin

LH, Miettinen M. Anorectal gastrointestinal stro-mal tumors: CT and MR imaging features withclinical and pathologic correlation.

AJR

2003;180:1607–1612

7. Megibow AJ, Balthazar EJ, Hulnick DH, NaidichDP, Bosniak MA. CT evaluation of gastrointesti-nal leiomyomas and leiomyosarcomas.

AJR

1985;144:727–7318. Chun HJ, Byun JY, Chun KA, et al. Gastrointestinal

leiomyoma and leiomyosarcoma: CT differentia-tion.

J Comput Assist Tomogr

1998;22:69–74 9. Miettinen M, El-Rifai W, H L Sobin L, Lasota J.

Evaluation of malignancy and prognosis of gas-trointestinal stromal tumors: a review.

HumPathol

2002;33:478–483 10. Silberman H, Crichlow RW, Caplan HS. Neo-

plasms of the small bowel.

Ann Surg

1974;180:157–161

11. Chen MY, Bechtold RE, Savage PD. Cysticchanges in hepatic metastases from gastrointesti-nal stromal tumors (GISTs) treated with Gleevec(imatinib mesylate).

AJR

2002;179:1059–106212. Choi BI, Kim KW, Han MC, Kim YI, Kim CW.

Solid and papillary epithelial neoplasms of the pan-creas: CT findings.

Radiology

1988;166:413–416 13. Buckley JA, Fishman EK. CT evaluation of small

bowel neoplasms: spectrum of disease.

Radio-Graphics

1998;18:379–392 14. Jayaraman MV, Mayo-Smith WW, Movson JS,

Dupuy DE, Wallach MT. CT of the duodenum: anoverlooked segment gets its due.

RadioGraphics

2001;21[spec no]:S147–S160

Dow

nloa

ded

from

ww

w.a

jron

line.

org

by U

nive

rsity

of

Vir

gini

a on

04/

16/1

3 fr

om I

P ad

dres

s 12

8.14

3.22

.132

. Cop

yrig

ht A

RR

S. F

or p

erso

nal u

se o

nly;

all

righ

ts r

eser

ved