AJR 2005; 185:704-707
© American Roentgen Ray Society
Xanthogranulomatous Pancreatitis Associated with Intraductal Papillary Mucinous Tumor
Takeshi Kamitani1,
Masaki Nishimiya1,
Naoki Takahashi2,
Yoshitaka Shida1,
Kanehiro Hasuo1 and
Hitohiko Koizuka3
1 Department of Radiology, International Medical Center of Japan, Shinjuku-ku,
Tokyo, Japan.
2 Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu
University, Higashi-ku, Fukuoka, Japan.
3 Department of Gastroenterology, International Medical Center of Japan,
Shinjuku-ku, Tokyo, Japan.
Received July 1, 2004;
accepted after revision October 8, 2004.
Address correspondence to T. Kamitani
(kamikamitani{at}ybb.ne.jp),
Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu
University, 3-1-1, Maidashi, Fukuoka, Japan 812-8582.
Introduction
Xanthogranulomatous inflammation is characterized histologically by
clumping of foam macrophages and infiltration of inflammatory cells
[1,
2]. These changes have been
found in the gallbladder, kidney, bone, ovary, endometrium, vagina, prostate,
lymph node, and in soft tissue
[1,
3]. However,
xanthogranulomatous changes in the pancreas are extremely rare. We report what
we believe to be the first case of xanthogranulomatous pancreatitis associated
with intraductal papillary mucinous tumor (IPMT).
Case Report
An 82-year-old man was referred to our hospital with left epigastralgia and
a pancreatic cystic mass, based on sonography. His blood count and serum
chemistry, including amylase, were within normal limits. Carcinoembryonic
antigen (CEA), carbohydrate antigen 19-9 (CA19-9), DUPAN-2, and Span-1 were
also normal. MDCT (Aquilion, Toshiba Medical Systems) was performed before and
after injection of 100 mL of iopamidol (Iopamiron 300, Nihon Schering) at 3
mL/sec. The arterial phase, portal phase, and delayed phase of scanning began
at 35, 47, and 67 sec, respectively, after the start of contrast material
injection. Scanning parameters for the arterial phase and the portal phase
were a collimation of 4 x 1 mm, a pitch of 5.5, and a 3-mm
reconstruction interval. Those for the delayed phase were a collimation of 4
x 5 mm, a pitch of 3, and a 5-mm reconstruction interval. This procedure
revealed a 3-cm cystic mass and many small cystic lesions in the body of the
pancreas (Fig. 1A). The
parenchyma of the pancreas around the cystic lesions showed gradual
enhancement. This enhancing lesion was ill-defined and close to the stomach,
and the border between the enhancing area and the gastric wall was unclear.
The main pancreatic duct in the tail region was dilated, and the splenic vein
was compressed. MRI (Magnetom Symphony, Siemens Medical Solutions) showed a
cystic mass with a thick wall (Figs.
1B, and
1C). The contents of the cyst
were hyperintense on T2-weighted images (turbo spin-echo sequences,
TR/TE/excitation 3,200/108 msec/4; 5-mm slice thickness), but the signal was
of lower intensity than that of a simple cyst
(Fig. 1B). On delayed-phase
fat-suppressed T1-weighted images (3D FLASH, TR/TE/excitation 4/1.9/1, 2.5-mm
slice thickness) after a 0.1 mmol/kg gadolinium DTPA (Magnevist, Nihon
Schering) injection at 2 mL/sec and a 90-sec delay, the border between the
enhanced wall of the lesion and the gastric wall was unclear, and the
surrounding enhancing area extended into the gastric wall, suggesting invasion
into the stomach (Fig. 1D).
Based on these results, it was strongly suspected that the tumor was
malignant. No definite finding of encasement of the splenic artery and other
arteries was seen on celiac angiography (not shown). The proximal splenic vein
was compressed by the pancreatic mass, but was not occluded, and no tumor
stain was present.
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Fig. 1A —82-year-old man with xanthogranulomatous pancreatitis.
Delayed-phase contrast-enhanced CT image shows 3-cm cystic mass (long
arrow) and many small cystic lesions (short arrow) in pancreas
body. Ill-defined enhancing area is seen around these cystic lesions. Main
pancreatic duct in tail region is dilated and splenic vein is compressed.
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Fig. 1B —82-year-old man with xanthogranulomatous pancreatitis.
T2-weighted image shows cystic masses (long and short arrows).
Contents of these cysts appear hyperintense, but appear to be of somewhat
lower intensity than that of a simple cyst.
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Fig. 1C —82-year-old man with xanthogranulomatous pancreatitis.
T1-weighted MR images with fat saturation show cystic mass and surrounding
enhancing area (long arrow, C). Border between mass and
gastric wall is unclear, and enhancing area extends into gastric wall
(arrowheads, D).
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Fig. 1D —82-year-old man with xanthogranulomatous pancreatitis.
T1-weighted MR images with fat saturation show cystic mass and surrounding
enhancing area (long arrow, C). Border between mass and
gastric wall is unclear, and enhancing area extends into gastric wall
(arrowheads, D).
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Based on a diagnosis of malignant tumor of the pancreas, distal
pancreatectomy, splenectomy, and partial gastrectomy were performed.
Histopathologically, many dilated pancreatic ducts were noted. Cystic
components detected by CT and MRI were thought to be marked dilated pancreatic
ducts. These dilated ducts were epithelized by micropapillary columnar mucous
cells, suggesting the presence of papillary mucinous adenoma
(Fig. 1E). The surrounding
pancreatic tissue was atrophic and infiltrated with many foamy macrophages,
lymphocytes, and plasma cells (Fig.
1F). These findings suggested the presence of xanthogranulomatous
inflammation, and a diagnosis of xanthogranulomatous pancreatitis was made.
Many foamy macrophages, lymphocytes, and plasma cells also existed in the
muscular layer of the stomach, suggesting the spread of infiltration to the
gastric wall (Fig. 1F). In
addition, pools of mucin were seen in the inflammatory foci
(Fig. 1G). In summary, the
cystic components were dilated pancreatic ducts containing mucin produced by
IPMT, and the surrounding enhancing area, which had spread to the gastric
wall, was the result of xanthogranulomatous pancreatitis. Because pools of
mucin were seen in the inflammatory region, it was concluded that
xanthogranulomatous inflammation was due to a reaction to mucin.
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Fig. 1E —82-year-old man with xanthogranulomatous pancreatitis.
Photomicrographs of histopathologic specimen show markedly dilated pancreatic
ducts with epithelium composed of micropapillary columnar mucous cells, which
suggest presence of papillary mucinous adenoma (E, H and E). Foamy
macrophages, lymphocytes, and plasma cells have excessively infiltrated
atrophic pancreatic tissue (F, H and E). Many foamy macrophages,
lymphocytes, and plasma cells also exist in muscular layer of stomach
(F). Pools of mucin (arrows, G) are seen in
inflammatory foci (G, H and E).
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Fig. 1F —82-year-old man with xanthogranulomatous pancreatitis.
Photomicrographs of histopathologic specimen show markedly dilated pancreatic
ducts with epithelium composed of micropapillary columnar mucous cells, which
suggest presence of papillary mucinous adenoma (E, H and E). Foamy
macrophages, lymphocytes, and plasma cells have excessively infiltrated
atrophic pancreatic tissue (F, H and E). Many foamy macrophages,
lymphocytes, and plasma cells also exist in muscular layer of stomach
(F). Pools of mucin (arrows, G) are seen in
inflammatory foci (G, H and E).
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Fig. 1G —82-year-old man with xanthogranulomatous pancreatitis.
Photomicrographs of histopathologic specimen show markedly dilated pancreatic
ducts with epithelium composed of micropapillary columnar mucous cells, which
suggest presence of papillary mucinous adenoma (E, H and E). Foamy
macrophages, lymphocytes, and plasma cells have excessively infiltrated
atrophic pancreatic tissue (F, H and E). Many foamy macrophages,
lymphocytes, and plasma cells also exist in muscular layer of stomach
(F). Pools of mucin (arrows, G) are seen in
inflammatory foci (G, H and E).
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Discussion
Xanthogranulomatous inflammation is characterized histologically by
clumping of foam macrophages and infiltration of inflammatory cells
[1,
2]. This is an uncommon
inflammatory response, but a relatively large number of cases of
xanthogranulomatous cholecystitis and xanthogranulomatous pyelonephritis have
been reported. Similar changes have also been found in the bone, ovary,
endometrium, vagina, prostate, lymph node and in soft tissue
[1,
3]. Although abscesses,
necrosis, and hemorrhage have been mentioned as causes, it has also been
suggested that obstructive conditions and infection particularly help to
induce xanthogranulomatous changes
[1]. Pressure in the
gallbladder may be elevated by a stone or a tumor in the neck of the
gallbladder or by postoperative retention of bile, which can cause intramural
extravasation of bile and mucin and result in xanthogranulomatous changes
[2-4].
Xanthogranulomatous pyelonephritis is also considered to be caused by
occlusion of the urinary tract and infection
[3].
Xanthogranulomatous changes in the pancreas are extremely rare, and to our
knowledge only one case of a similar change has been reported
[1]. In that case, it was
speculated that infection and hemorrhage occurred in a pseudocyst formed after
acute alcoholic pancreatitis and elevated intracystic pressure, leading to
xanthogranulomatous changes around the pancreatic cyst wall. In our case, we
were able to prove marked dilation of the pancreatic duct due to IPMT and
identify pools of mucin in the inflammatory region. We concluded that mucin
produced by IPMT increased the intraductal pressure and that this resulted in
a leak of mucin into the pancreatic parenchyma, with the xanthogranulomatous
changes occurring as a reaction to the mucin. It is unclear why
xanthogranulomatous pancreatitis is so rare, given that pancreatic cancers,
pancreatitis, and other inflammatory causes of ductal obstruction are common.
However, this is consistent with the relative rarity of xanthogranulomatous
cholecystitis and xanthogranulomatous pyelonephritis. It is also of note that
our case was proven to be xanthogranulomatous pancreatitis because malignancy
was suspected and surgery was performed. Other cases of xanthogranulomatous
pancreatitis may actually be treated as normal pancreatitis.
Xanthogranulomatous cholecystitis is characterized by a markedly thickened
gallbladder wall with infiltration and adhesion to surrounding tissue, and
differentiation of this condition from gallbladder cancer is often difficult
[3,
5]. Although the presence of
intramural low attenuation nodules over a large area of the thickened
gallbladder wall, representing abscesses or xanthogranulomas, is highly
suggestive of xanthogranulomatous cholecystitis
[2-4],
it is also common for this finding not to be present
[2]. Xanthogranulomatous
pyelonephritis also shows multiple low attenuation areas representing dilated
calices and abscesses [6]. Low
attenuation areas were also seen in our case, but these were dilated
pancreatic ducts. Because of marked infiltration, differentiation from
malignancy was difficult, although the absence of definite arterial
encasement, despite marked infiltration into the stomach, was helpful in
making a differential diagnosis. In addition, the infiltrating soft tissue was
very vascular and showed prominent enhancement on CT. This is also atypical
for pancreatic adenocarcinoma and IPMT lesions and may help to differentiate
xanthogranulomatous pancreatitis from an infiltrating tumor.
To our knowledge, xanthogranulomatous pancreatitis has not been reported in
the English literature, except for one paper describing changes with
xanthogranulomatous characteristics
[1]. Hence, this is the first
case report of xanthogranulomatous pancreatitis, which in our case developed
as a complication of IPMT. Although it is rare, we consider this disease to be
important because it may produce imaging features that mimic malignancy.
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Introduction
Case Report
