Mucinous Cystadenomas and Intraductal Papillary Mucinous Tumors of the Pancreas in Magnetic Resonance Cholangiopancreatography

• Introduction
• Patients and Methods
• Patients
• Technique
• Results
• Discussion
• Acknowledgement
• References

Background and Study Aims: In mucin-producing tumors of the pancreas, diagnosis using endoscopic retrograde cholangiopancreatography (ERCP) is limited to cystic formations that communicate with the main pancreatic duct. Magnetic resonance cholangiopancreatography (MRCP) is a new, sophisticated method which is currently under evaluation. The authors describe the usefulness of MRCP in diagnosis of mucin-producing tumors.

Patients and Methods: Six patients with mucin-producing tumors were investigated using MRCP and ERCP. Imaging was compared with surgery and histopathological examinations.

Results: Three patients were found to have mucinous cystadenomas (MC), two patients had intraductal papillary mucinous tumors (IPMT) and one patient had a cystadenocarcinoma. MRCP demonstrated the cystic formations in all patients. Magnetic resonance imaging (MRI) showed contrast-mediated enhancement of the cystic wall in patients with MC, and visualized the pancreatic ducts completely in patients with IPMT. ERCP failed to visualize the cystic lesion in one patient with MC of the pancreatic tail. Furthermore, ERCP showed evidence of IPMT in dilated main ducts with multiple filling defects but did not visualize the ducts completely.

Conclusions: MRCP provides visualization of pancreatic ducts, extraductal variations, and cystic formations more completely than ERCP does. It avoids complications seen in ERCP. MRCP may replace ERCP in the evaluation of mucin-producing tumors of the pancreas.

Introduction

Cystic tumors of the pancreas which produce mucin account for about 1 % of pancreatic neoplasms [1]. Intraductal papillary mucinous tumors (IPMTs) of the pancreas which originate from the main pancreatic duct and its collateral branches are distinguished from mucinous cystadenomas (MCs) which derive from the peripheral ducts [2] [3] .

Characteristic features of IMPTs in endoscopic retrograde cholangiopancreatography (ERCP) are mucin protrusion from the papilla of Vater, gross dilation of the main pancreatic duct, and opacification of the cystic lesions [4]. In MCs, irregular dilated ducts and, infrequently, cystic formations can be shown by ERCP.

Magnetic resonance cholangiopancreatography (MRCP) is emerging as a routinely applied method for imaging the biliopancreatic system with a considerable effect on established diagnostic procedures. Diagnostic ERCP, for example, has already been replaced by MRCP in some instances of biliopancreatic investigation [5].

The aim of this study is to show the feasibility of MRCP in diagnosing mucin-producing tumors of the pancreas.

Patients and Methods

Patients

Between May 1996 and April 1998, six patients were examined using MRCP and were found to have mucin-producing tumors of the pancreas. Subsequently, the histopathologic diagnosis was obtained postoperatively and was correlated with MRCP and ERCP findings.

The study group consisted of four women and two men, ranging in age from 41 to 73 years. Three patients presented with episodes of epigastric pain; three had no clinical symptoms and were referred for control of a pancreatic lesion that had been detected using routine abdominal ultrasonography. Two patients had diabetes mellitus (patients 1 and 4), and one patient had a history of more than 10 years of chronic pancreatitis and alcoholic abuse (patient 5). Two patients had been previously diagnosed with an upper abdominal cyst after abdominal ultrasonography investigation (patient 1 3 years and patient 3 13 years before MR studies).

Technique

Complete pancreatograms were obtained in all patients in the standard manner with selective cannulation of the pancreatic duct.

All MR studies were carried out using a 1,0 T superconducting unit (Magnetom Expert; Siemens, Erlangen, Germany) with a phased array body coil, using a single breath-hold technique for coronal and transversal T₂-weighted turbo spin echo (TSE/TR 2280 ms; TE 138 ms) and T₁-weighted gradient echo (GRE/TR 163 ms; TE 4.8 ms) with and without fat saturation technique; and the addition of T₂-weighted single-shot RARE and HASTE sequences (TR 10.9 ms, TE 87.0 ms) were used for MRCP. Contrast medium (gadolinium-DTPA, Magnevist; Schering) was administered intravenously in all cases (0.2 mmol/kg bodyweight). Two radiologists experienced in gastrointestinal imaging and one gastroenterologist reviewed the MRCP results on hard copy films and/or at the diagnostic work-station. None of the reviewers were informed of the clinical results nor of previous imaging examinations.

MRCP and MR tomograms (MRTs) were compared with the following imaging modalities: ERCP in five cases; endoscopical ultrasound (EUS) in five patients; and computed tomography (CT) in four patients; pancreatoscopy was performed in three patients.

Four patients underwent distal pancreatectomy, three of them with additional splenectomy. In two patients, pancreaticoduodenectomy (Whipple resection) was carried out.

Results

MRCP was performed without complications in all patients. This imaging method allowed the examiners to visualize the biliary tract, the pancreatic duct, and the cystic tumors completely in all six patients (Table [1]). It demonstrated masses of multilobular and irregularly marginated cysts with thick septations in three patients (patients 1, 2, and 3; cf. Figure [1]); any of the main pancreatic ducts was dilated in these patients. The cyst wall was enhanced after application of contrast medium.

In patient 4, MRCP showed a smoothly demarcated cystic tumor that was located at the transition area between pancreatic body and tail. The main pancreatic duct showed an impression at this site.

A cluster of cystic structures of up to 3 cm in diameter was demonstrated by MRCP in patient 5 (Figure [2]). The structure showed contrast medium-mediated wall enhancement. The pancreatic duct appeared dilated at the site of the pancreatic body. Lymph node or liver metastases were not seen.

In patient 6, MRCP showed a cystic tumor of about 3 cm in diameter at the upper part of the pancreatic body. Application of contrast medium led to a visible enhancement of the lesion, and dilation of the pancreatic duct was not observed.

ERCP showed no significant dilation of the pancreatic duct in patients 1, 2, and 3, and neither was the cystic lesion of patient 5 seen at MRCP revealed on ERCP (Figures [3] and [4]) nor the communicating duct. A cystic formation was visible in patient 3. In patient 4, ERCP revealed minimal cystic variations in branches of the pancreatic duct, and a stenosis of the pancreatic duct was seen at the pancreatic body. Leakage of mucin through the orifice of the papilla was shown only in patient 5. In this patient, a bulging papilla of Vater was seen with protrusions of mucinous masses. In patient 6, a ductal stenosis of the pancreatic body was shown by ERCP. Details of additional diagnostic methods and histological results are presented in Table [1].

Discussion

ERCP has emerged as the preferred diagnostic procedure in the examination of biliopancreatic disease over the last three decades. However, ERCP is an uncomfortable procedure accompanied by a complication rate of about 5 % [6] [7] and can demonstrate extraductal changes only indirectly. Today, MRCP has proved to be equivalent to ERCP in the diagnostic accuracy of several pancreatic diseases without the morbidity that is associated with ERCP [5] [8] [9] .

In the current World Health Organization (WHO) classification, IPMT, formerly a subgroup of mucinous cystadenomas, is now separately classified (Table [2]). A sequence of malignancy evolving from benign, mucinous neoplasm is presumed in IPMT and in MC, and is reflected in the actual WHO classification of tumors on the basis of the ICD-O (Table [2]) [10]. Diagnosis of MC or IPMT is important because of the favorable prognosis in comparison with ductal pancreatic carcinoma given a timely diagnosis [11]. Organ-preserving operations may be preferentially performed.

IPMTs are mainly found in the pancreatic head of elderly men with an average age between 60 and 70 years, as seen in patients 5 and 6 of this series. IPMT is characterized by dilation of the main and/or collateral pancreatic ducts and by secretion of large quantities of mucous into the ductal lumen. The main symptom of its manifestation is recurrent acute pancreatitis, which is brought on by the obstruction of pancreatic ducts by mucin. The long-term prognosis depends on the grade of dysplasia [11].

In two cases of IPMT, ERCP demonstrated gross dilation of pancreatic duct with inhomogeneous filling defects; the cystic dilations were seen more completely on MRCP. MRCP revealed evidence of discrete hemorrhagia - a feature that cannot be diagnosed by ERCP. Pancreatoscopy showed a floating tumor or mural nodules and stenosis of the pancreatic duct. EUS showed normal findings and therefore could not add diagnostic information to other imaging modalities.

MCs, which are predominantly found in middle-aged women, are large, multiloculated cystic masses that arise in the pancreatic tail [1]. They do not communicate with the pancreatic duct unless a fistula has developed.

In our series, there were three instances of MCs localized in the pancreatic tail in female patients. ERCP showed the cystic lesion in one case only, whereas MRCP visualized the formation completely in all of these cases. Pancreatoscopy, which was performed in one case, only showed segmentary ductectasia and did not yield additional information to ERCP. The use of pancreatoscopy should remain restricted to IPMT of the pancreas.

Several reports confirm our findings [12] [13] [14] . In MC, MRCP is shown to be more accurate, and to show the cystic formations and the dilated ductal branches more completely than ERCP because the cysts are not connected to the main pancreatic duct [12].

As far as IPMT is concerned, ERCP remains the imaging modality of choice, but the use of MRCP may yield additional information as it visualizes the tumor as a whole [12] [13] [14] [15] . Nevertheless, inspection of the papilla is only possible in ERCP and this is the only means for visualizing protrusion of mucin through a patulous orifice. Additional pancreatoscopy may be needed for the detection of flat lesions in IPMT [16].

The combination of ERCP plus pancreatoscopy may be helpful in the diagnosis of IPMT [17] [18] but does not contribute much to the diagnosis of MC of the pancreas [19].

Using CT, enhancement of the hypervascularized mucin-producing tumors and, in angiography, neovascularization and vascular blush are commonly seen [1]. In the current study, an enhancement of the cystic wall after application of contrast medium was noticed in all cases of MC and cystadenocarcinoma. To the authors' knowledge, the use of gadolinium-DTPA in the diagnosis of MC has not been reported so far. It is proposed that gadolinium-DTPA should be routinely applied if pancreatic cystic neoplasms are suspected.

In conclusion, MRCP provides similar or even better results in the diagnosis of patients with mucin-producing tumor of the pancreas than those provided by ERCP. MRCP can replace ERCP as a diagnostic procedure as it is noninvasive and demonstrates the tumor and the ductal and cystic lesions more completely than ERCP.

Acknowledgement

We greatly appreciate the assistance of Crystal Rieger in the preparation of this manuscript.

References

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H. E. Adamek, M.D.

Medizinische Klinik C Klinikum Ludwigshafen

Bremserstrasse 79 67063 Ludwigshafen Germany

Fax: Fax:+ 49-621-503-4112

Email: E-mail:MedCLu@t-online.de

References

• 1 Buetow P C, Rao P, Thompson L DR. Mucinous cystic neoplasms of the pancreas: radiologic-pathologic correlation.  RadioGraphics. 1998;  18 433-449
  PubMedSearch in Google Scholar
• 2 Loftus E V, Olivares-Pakzad B A, Batts K P, et al. Intraductal papillary-mucinous tumors of the pancreas: clinicopathologic features, outcome, and nomenclature.  Gastroenterology. 1996;  110 1909-1918
  CrossrefPubMedSearch in Google Scholar
• 3 Siech M, Tripp K, Schmidt-Rohlfing B, et al. Intraductal papillary mucinous tumor of the pancreas.  Am J Surg. 1999;  177 117-120
  CrossrefPubMedSearch in Google Scholar
• 4 Pavone E, Metha S N, Hilzenrat N, et al. Role of ERCP in the diagnosis of intraductal papillary mucinous neoplasms.  Am J Gastroenterol. 1997;  92 877-890
  PubMedSearch in Google Scholar
• 5 Devière J, Matos C, Cremer M. The impact of magnetic resonance cholangiopancreatography on ERCP.   Gastrointest Endosc. 1999;  50 136-140 (discussion: 140 - 143)
  PubMedSearch in Google Scholar
• 6 Loperfido S, Angelini G, Benedetti G, et al. Major early complications from diagnostic and therapeutic ERCP: a prospective multicenter study.  Gastrointest Endosc. 1998;  48 1-10
  CrossrefPubMedSearch in Google Scholar
• 7 Sherman S, Lehman G A. ERCP- and endoscopic sphincterotomy-induced pancreatitis.  Pancreas. 1991;  6 350-367
  PubMedSearch in Google Scholar
• 8 Albert J, Adamek H E, Weitz M, et al. The place of MR-cholangiopancreatography in the diagnosis of biliary-pancreatic disease (review).  Dtsch Med Wochenschr. 1998;  123 1149-1155
  PubMedSearch in Google Scholar
• 9 Soto J A, Barish M A, Yucel E K, et al. Pancreatic duct: MR cholangiopancreatography with a three-dimensional fast spin echo technique.  Radiology. 1995;  196 459-464
  PubMedSearch in Google Scholar
• 10 Grundmann E, Hermanek P, Wagner G. Tumorhistologieschlüssel. 2nd edn.  Berlin; Springer, 1997: 64-71
• 11 Cellier C, Cuillerier E, Palazzo L, et al. Intraductal papillary and mucinous tumors of the pancreas: accuracy of preoperative computed tomography, endoscopic retrograde pancreatography and endoscopic ultrasonography, and long-term outcome in a large surgical series.  Gastrointest Endosc. 1998;  47 42-49
  CrossrefPubMedSearch in Google Scholar
• 12 Koito K, Namieno T, Ichimura T, et al. Mucin-producing tumor of the pancreas: comparison of MR cholangiopancreatography with ER cholangiopancreatography.  Radiology. 1998;  208 231-237
  PubMedSearch in Google Scholar
• 13 Fukukura Y, Fujiyoshi F, Sasaki M, et al. HASTE MR cholangiopancreatography in the evaluation of intraductal papillary-mucinous tumors of the pancreas.  J Comp Assist Tomography. 1999;  23 301-305
  PubMedSearch in Google Scholar
• 14 Sugiyama M, Atomi Y, Hachiya J. Intraductal papillary tumors of the pancreas: evaluation with magnetic resonance cholangiopancreatography.  Am J Gastroenterol. 1998;  93 156-159
  CrossrefPubMedSearch in Google Scholar
• 15 Onaya H, Itai Y, Niitsu M, et al. Ductectatic mucinous cystic neoplasms of the pancreas: evaluation with MR cholangiopancreatography.  Am J Roentgenol. 1998;  171 171-177
  PubMedSearch in Google Scholar
• 16 Myung S J, Kim M H, Kim H J, et al. Magnetic resonance cholangiopancreatography is insufficient for the detection of flat lesions in mucinous ductal ectasia: pancreatoscopy may be needed additionally.  Am J Gastroenterol. 1998;  93 1189
  PubMedSearch in Google Scholar
• 17 Tajiri H, Kobayashi M, Ohtsu A, et al. Peroral pancreatoscopy for the diagnosis of pancreatic disease.  Pancreas. 1998;  16 408-412
  PubMedSearch in Google Scholar
• 18 Jung M, Zipf A, Schoonbroodt D, et al. Is pancreatoscopy of any benefit in clarifying the diagnosis of pancreatic duct lesions?.  Endoscopy. 1998;  30 273-280
  PubMedSearch in Google Scholar
• 19 Kaneko T, Nakao A, Nomoto S, et al. Intraoperative pancreatoscopy with the ultrathin pancreatoscope for mucin-producing tumors of the pancreas.  Arch Surg. 1998;  133 263-267
  PubMedSearch in Google Scholar

H. E. Adamek, M.D.

Medizinische Klinik C Klinikum Ludwigshafen

Bremserstrasse 79 67063 Ludwigshafen Germany

Fax: Fax:+ 49-621-503-4112

Email: E-mail:MedCLu@t-online.de