DOI:10.2214/AJR.05.0292
AJR 2006; 187:W604-W606
© American Roentgen Ray Society
Intraductal Papillary Mucinous Tumors of the Pancreas: Branch Duct Tumor Penetrating the Stomach and Duodenum
InHo Lee1,
Jae Hoon Lim1,
Dongil Choi1,
Kee-Taek Jang2,
Kyu Taek Lee3 and
Seong-Ho Choi4
1 Department of Radiology and Center for Imaging Science, Samsung Medical
Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku,
Seoul, Korea 135-710.
2 Department of Pathology, Samsung Medical Center, Sungkyunkwan University
School of Medicine, Seoul, Korea.
3 Department of Gastroenterology, Samsung Medical Center, Sungkyunkwan
University School of Medicine, Seoul, Korea.
4 Department of Surgery, Samsung Medical Center, Sungkyunkwan University School
of Medicine, Seoul, Korea.
Received February 21, 2005;
accepted after revision May 29, 2005.
Address correspondence to J. H. Lim
(jhlim{at}smc.samsung.co.kr).
WEB
This is a Web exclusive article.
Keywords: CT • cysts • MRI • oncologic imaging • pancreas • pancreatic ducts • pancreatic neoplasms
Introduction
Intraductal papillary mucinous tumor (IPMT) of the pancreas is a neoplasm
that develops from the epithelial lining of pancreatic ducts. It involves the
main pancreatic duct, the branch pancreatic ducts, or both, and it secretes a
large amount of thick mucin, which leads to intermittent ductal obstruction
and dilation. In the main duct type of IPMT, the main pancreatic duct is
diffusely dilated because the mucin impedes the passage of main duct flow,
whereas in the branch duct type of IPMT, some of branch ducts dilate
cystically
[1-4].
Although intraductal tumor may appear as a small, flat, or nodular mass, the
tumor sometimes spreads superficially along the lumen of a lengthy segment of
the pancreatic ducts [3,
4]. Tumor spread depends on the
invasiveness of the tumor—from benign or borderline malignancy to
relatively aggressive tumor. However, superficially spreading aggressive tumor
growth along the entire main pancreatic duct and branch ducts with extension
to adjacent organs has not been described. We report a case of IPMT with
diffuse involvement of the entire pancreatic ductal system with contiguous
spread to adjacent gastric and duodenal walls.
Case Report
A 58-year-old man had intermittent epigastric pain for 13 years. A CT scan
obtained 8 years earlier showed a segmental tubular dilation of the main
pancreatic duct at the tail. He had been managed with the diagnosis of
recurrent pancreatitis.
CT performed 8 years later showed an enlarged pancreas and severe dilation
of the main pancreatic duct and of pancreatic branch ducts. In the pancreatic
tail, there was a large, cystically dilated main pancreatic duct, measuring 6
cm in diameter (Fig. 1A). In
addition, one branch duct drained directly into the second portion of the
duodenum (Figs. 1A and
1B). Several small cystic
lesions had developed in the pancreatic head and neck. A defect in the stomach
wall was observed. On subsequent duodenal endoscopy, mucin was observed to
gush from the orifice of the major papilla. MR cholangiopancreatography showed
that the main pancreatic duct was markedly dilated, as were many branch ducts,
including several cystically dilated ducts
(Fig. 1C).
View larger version (133K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1A —58-year-old man with intraductal papillary mucinous tumor of
pancreas. CT scan at level of pancreas body reveals diffusely enlarged
pancreas, markedly dilated, tortuous main pancreatic duct (white
arrows), and cystically dilated duct at pancreas tail (black
arrow). Note abnormal channel between dilated main pancreatic duct and
duodenum (D).
|
|
View larger version (135K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1B —58-year-old man with intraductal papillary mucinous tumor of
pancreas. CT scan at level of pancreatic head reveals dilated main pancreatic
duct (black arrow) and accessory pancreatic duct (white
arrow). Note cystic dilation of branch duct (asterisk). D =
duodenum.
|
|
View larger version (125K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1C —58-year-old man with intraductal papillary mucinous tumor of
pancreas. Maximum-intensity-projection MR cholangiopancreatography image shows
diffusely dilated main pancreatic duct, many branch ducts along pancreas body
and tail, and cystically dilated duct at pancreatic tail (asterisk).
Note dilated main pancreatic duct (white arrow) and abnormal channel
at neck draining into duodenum (black arrow). CBD = common bile duct,
G = fluid in gastric fundus.
|
|
At surgery, the pancreas was swollen and attached to the transverse
mesocolon and superior mesenteric vein. Additionally, the pancreas tail was
found to be tightly attached to the fundus of the stomach. There was a tiny
wall defect in the gastric fundus and a small amount of mucin in the gastric
lumen. A curative resection of the whole pancreas and spleen was performed,
including the common bile duct, gastric antrum, and duodenum, and wedge
resection of the gastric fundus was also performed. Hepaticojejunostomy and
gastrojejunostomy were performed. The resected specimen showed markedly
dilated main and branch pancreatic ducts (8-9 mm) that were filled with
mucin.
A pathologic examination disclosed intraductal papillary mucinous carcinoma
diffusely involving the entire main pancreatic duct and many of the branch
ducts. The main and branch ducts were lined diffusely by one layer of tumor
cells and were filled with mucin. Connections were observed between the
dilated branch pancreatic ducts and the lumen of the stomach and duodenum (two
connections to each), which were also lined with tumor cells that had grown
into their lumina (Fig. 1D).
The fistulalike tract was lined by tumor cells and there was neoplastic
involvement of the orifice at the duodenum. Mucin and tumor debris were
observed around the orifices of these abnormal connections.
View larger version (131K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1D —58-year-old man with intraductal papillary mucinous tumor of
pancreas. Microphotograph of pathologic specimen at site of fistulalike
connection through duodenal wall (thick arrows) between dilated
pancreatic duct and duodenal lumen. Tumor cells line fistulalike tract
(thin arrow), penetrate duodenal wall, and grow over duodenal mucosa
(Dm). Note tumor debris (arrowheads) in duodenal lumen at orifice of
fistulalike tract. m = mucin, g = granuloma adjacent to fistulalike tract. (H
and E, x 40)
|
|
Discussion
IPMT of the pancreas is characterized by diffuse or segmental dilation of
the main pancreatic duct (main duct type), cystic dilation of the branch ducts
of the uncinate process (branch duct type), or dilation of the main duct and
of the branch ducts (combined type)
[1-4].
The localized form of the tumor usually produces a nodular or polypoid mass in
the main pancreatic duct or in one of the branch ducts. However, tumors can
grow in a diffuse form as a single layer of tumor cells that diffusely line
long segments of the main or branch pancreatic ducts
[3], and sometimes the entire
ductal system may be involved.
In the present case, the entire ductal system, including branch ducts, was
dilated diffusely, and connections were observed between some of the dilated
branch ducts of the pancreas and the lumina of the stomach and duodenum. These
connecting branch ducts were lined with tumor cells that had penetrated the
lumen of the duodenum. This type of connecting tumor growth is different from
the fistula formation caused by mechanical compression of the dilated
pancreatic duct [4] in cases of
chronic pancreatitis.
Mucinous tumors of other organs, such as the stomach, colon, and ovary, may
extend to an adjacent organ by direct tumor invasion or lymphovascular
invasion. However, our patient showed fistulalike tumor growth to the stomach
and duodenum. It was not a true fistula tract, because the connecting tract
was lined by tumor cells. Because the mucin is thick and viscid, drainage of
pancreatic juice and mucin through the Santorini and Wirsung ducts is
hampered, and the intraductal pressure increases. Thus, some of the branch
ducts at the periphery of the pancreas may rupture.
View larger version (26K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2 —Schematic drawing of dilated main pancreatic duct and branch
ducts that were lined by single layer of tumor cells. Two abnormal connections
were found between stomach and dilated pancreatic ducts, one through
cystically dilated main pancreatic duct at tail and other through dilated
branch duct. Two further abnormal connections were observed between duodenum
and dilated branch ducts of pancreatic head other than major (M) and minor (m)
papillary orifices. Note mucin draining into lumen of stomach and duodenum
through abnormal connections.
|
|
Cancer cells, spreading from the ruptured ducts into the adjacent stomach
and duodenal wall, continue to grow, eventually eroding the wall and entering
the lumen (Fig. 2). Superficial
spread along the mucosa of the pancreatic duct is a characteristic of IPMT,
and in this case, the aggressiveness of that spread explains the involvement
of the whole pancreatic ductal system and the penetration of the cancer cells
into some of branch ducts through the stomach and duodenal wall.
References
- Itoh S, Ishiguchi T, Ishigki T, Sakuma S, Maruyama K, Senda K.
Mucin-producing pancreatic tumor: CT findings and histopathologic correlation.
Radiology 1992;183
: 81-86[Abstract/Free Full Text]
- Procacci C, Grazinai R, Bicego E, et al. Intraductal
mucin-producing tumors of the pancreas: imaging findings.
Radiology 1996;198
: 249-257[Abstract/Free Full Text]
- Lim JH, Lee G, Oh YL. Radiologic spectrum of intraductal papillary
mucinous tumor of the pancreas. RadioGraphics2001; 21:323
-340[Abstract/Free Full Text]
- Procacci C, Carbognin G, Biasiutti C, Guarise A, Ghirardi C,
Schenal G. Intraductal papillary mucinous tumors of the pancreas: spectrum of
CT and MR findings with pathologic correlation. Eur
Radiol 2001; 11:1939
-1951[CrossRef][Medline]
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
Top
Introduction
Case Report
