- Case report
- Open Access
Intraductal papillary mucinous neoplasm in an annular pancreas: a case report
© Kobayashi et al. 2015
Received: 4 February 2015
Accepted: 7 August 2015
Published: 25 August 2015
Annular pancreas is a rare anomaly in which a ring of pancreatic tissue encircles the second portion of the duodenum. We herein report a case involving a 79-year-old Japanese man with an intraductal papillary mucinous neoplasm (IPMN) of the pancreas. Imaging studies showed that the pancreatic tissue encircled the descending part of the duodenum and that a 30-mm-diameter cystic tumor was present in the annular segment, leading to the diagnosis of pancreatic IPMN. Limited pancreatic resection was successfully performed by careful division of the annular segment from the second portion of the duodenum. The postoperative course was uneventful, and the patient’s pancreatic function was retained without the need for supplementation. To the best of our knowledge, this is the first report of IPMN occurring in the annular segment of the pancreas. Limited resection of the pancreatic annular segment is a feasible surgical treatment for noninvasive IPMN of the annular pancreas.
Annular pancreas is a rare congenital anomaly caused by malrotation of the pancreatic ventral bud during embryonic development. This condition was first reported by Tiedemann in 1818 . Autopsy and intraoperative studies have estimated the incidence of annular pancreas to be approximately 5 to 15 cases per 100,000 patients . The coexistence of an annular pancreas with a pancreatic neoplasm is therefore exceptionally rare.
We herein report a case of an intraductal papillary mucinous neoplasm (IPMN) in an annular pancreas.
The literature of pancreatic neoplasm associated with annular pancreas
Matsusue et al. 
Kamisawa et al. 
Yasui et al. 
Ben-David et al. 
Cholet et al. 
Ijichi et al. 
Milone et al. 
Limited pancreatic resection
IPMNs are characterized by cystic dilation of the main and/or branched pancreatic ducts and intraductal proliferation of neoplastic mucinous cells arranged into papillary structures [17, 18]. These tumors have a wide spectrum of atypical grades ranging from low-grade dysplasia to invasive carcinoma . The diagnosis of IPMN of the pancreas has markedly increased in the last few decades because of the widespread use of high-resolution imaging [20, 21]. IPMNs are classified as main duct type, branch duct type, and combined type, according to the area of involvement of the pancreatic ductal system [22, 23]. The present patient had a branch duct type of IPMNs (adenoma) with low-grade malignancy [22, 23]. However, the patient experienced abdominal pain, and the diameter of the tumor was large (30 mm). Although there is a controversy regarding whether pancreatic resection or close follow-up should be performed to treat IPMNs with low-grade malignant potential, especially in cases similar to the present case, we performed surgical extirpation of the tumor according to the Sendai consensus guidelines [21–26].
Various operative procedures are available to treat IPMNs with a low risk of malignancy [27–30]. Nakagohri et al. reported good surgical outcomes for noninvasive or minimally invasive IPMNs after inferior pancreatic head resection . In this procedure, the uncinate process and pancreatic parenchyma around the duct of Wirsung are resected, preserving the pancreatic head around the duct of Santorini . Takada described ventral pancreatectomy, which involves resection of only the ventral segment of the pancreas, preserving the dorsal segment and the main pancreatic duct . Of course, division of the annular segment is generally not recommended because of the high incidence of postoperative complications such as fistula formation, pancreatitis, pancreatic laceration, and/or recurrent duodenal stenosis secondary to local fibrosis [5, 33, 34]. Thus, in the present case, the resection area was very carefully determined, and an additional procedure was performed to avoid postoperative complications.
In many cases, the pancreatic annulus cannot be separated because of the dense adhesion between the duodenum and annulus . In our case, however, the adhesion between the annular segment and second portion of duodenum was fortunately loose, and we easily ligated the annular pancreatic duct. The annular segment (including the tumor) was removed, and the pancreatic head around the duct of Santorini was preserved. Additionally, the second portion of the duodenum and the pancreatic stump were covered by the jejunum to prevent duodenal leakage and pancreatic fistula formation. The present case suggests that limited annular pancreatic resection is safe when the adhesion between the duodenum and annular segment is loose and the locations of the annular pancreatic duct and the duct of Santorini are definitively identified. However, the precise indications for this procedure remain to be elucidated.
In conclusion, the possibility of coexisting pancreatobiliary disorders such as IPMNs should be kept in mind in adult patients with an annular pancreas. Partial resection of the pancreas, including division of the annular segment, may be safe and effective in selected patients.
Written informed consent was obtained from the patient for publication of this case report and any accompanying images.
The authors thank Amane Kitasato, Tomohiko Adachi, and Shinya Onizuka for their constructive advice.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
- Tiedemann F. Uber die Verschiedenheiten des Ausfuhrungsganges der Bauchspeicheldruse bei den Menschen und Saugetieren. Dtsch Arch Physiol. 1818;4:403.Google Scholar
- Ravitch MM, Woods Jr AC. Annular pancreas. Ann Surg. 1950;132(6):1116–27.PubMedPubMed CentralView ArticleGoogle Scholar
- Lecco T. Zur morphologie des pancreas annulare. Sitzungberichte de Kaiserlichen Akademie der Wissenschaften. 1910;69:391–406.Google Scholar
- Baldwin WA. A specimen of annular pancreas. Anat Rec. 1910;4(8):299–304.View ArticleGoogle Scholar
- Zyromski NJ, Sandoval JA, Pitt HA, Ladd AP, Fogel EL, Mattar WE, et al. Annular pancreas: dramatic differences between children and adults. J Am Coll Surg. 2008;206(5):1019–25. discussion 25–7.PubMedView ArticleGoogle Scholar
- Matsusue S, Kashihara S, Koizumi S. Pancreatectomy for carcinoma of the head of the pancreas associated with multiple anomalies including the preduodenal portal vein. Jpn J Surg. 1984;14(5):394–8.PubMedView ArticleGoogle Scholar
- Yasui A, Nimura Y, Kondou S, Kamiya J. Duodenal obstruction due to annular pancreas associated with pancreatic head carcinoma. Hepatogastroenterology. 1995;42(6):1017–22.PubMedGoogle Scholar
- Kamisawa T, Tabata I, Isawa T, Ishiwata J, Fukayama M, Koike M. Annular pancreas associated with carcinoma in the dorsal part of pancreas divisum. Int J Pancreatol. 1995;17(2):207–11.PubMedGoogle Scholar
- Ben-David K, Falcone Jr RA, Matthews JB. Diffuse pancreatic adenocarcinoma identified in an adult with annular pancreas. J Gastrointest Surg. 2004;8(5):565–8.PubMedView ArticleGoogle Scholar
- Cholet F, Bideau K, Nonent M, Nousbaum JB, Gouerou H, Robaszkiewicz M. Coexistence of annular pancreas with carcinoma in the dorsal part of pancreas divisum: diagnostic value of magnetic resonance cholangiopancreatography. Abdom Imaging. 2004;29(6):703–6.PubMedView ArticleGoogle Scholar
- Ijichi H, Nishizaki T, Terashi T, Shiraishi T, Takahashi I, Wada H, et al. Coexistence of mucinous cystic neoplasm occurring in the head of the pancreas with annular pancreas: report of a case. Surg Today. 2009;39(10):897–900.PubMedView ArticleGoogle Scholar
- Milone L, Okhunov Z, Gumbs AA. Laparoscopic diagnosis of annular pancreas in a patient with mucinous cystoadenoma of the body of the pancreas. J Gastrointest Cancer. 2012;43(2):367–9.PubMedView ArticleGoogle Scholar
- Traverso LW, Kozarek RA, Simpson T, Galagan KA. Pancreatic duct obstruction as a potential etiology of pancreatic adenocarcinoma: a clue from pancreas divisum. Am J Gastroenterol. 1993;88(1):117–9.PubMedGoogle Scholar
- Nishino T, Toki F, Oi I, Oyama H, Hatori T, Shiratori K. Prevalence of pancreatic and biliary tract tumors in pancreas divisum. J Gastroenterol. 2006;41(11):1088–93.PubMedView ArticleGoogle Scholar
- Adachi T, Tajima Y, Kuroki T, Mishima T, Kitasato A, Fukuda K, et al. Bile-reflux into the pancreatic ducts is associated with the development of intraductal papillary carcinoma in hamsters. J Surg Res. 2006;136(1):106–11.PubMedView ArticleGoogle Scholar
- Lahmar A, Abid SB, Arfa MN, Bayar R, Khalfallah MT, Mzabi-Regaya S. Metachronous cancer of gallbladder and pancreas with pancreatobiliary maljunction. World J Gastrointest Surg. 2010;2(4):143–6.PubMedPubMed CentralView ArticleGoogle Scholar
- Sadakari Y, Ienaga J, Kobayashi K, Miyasaka Y, Takahata S, Nakamura M, et al. Cyst size indicates malignant transformation in branch duct intraductal papillary mucinous neoplasm of the pancreas without mural nodules. Pancreas. 2010;39(2):232–6.PubMedView ArticleGoogle Scholar
- Ohno E, Itoh A, Kawashima H, Ishikawa T, Matsubara H, Itoh Y, et al. Malignant transformation of branch duct-type intraductal papillary mucinous neoplasms of the pancreas based on contrast-enhanced endoscopic ultrasonography morphological changes: focus on malignant transformation of intraductal papillary mucinous neoplasm itself. Pancreas. 2012;41(6):855–62.PubMedView ArticleGoogle Scholar
- Thompson R. Cancer: epithelial subtype influences the prognosis of invasive IPMN. Nat Rev Gastroenterol Hepatol. 2011;8(8):420.PubMedView ArticleGoogle Scholar
- Gourgiotis S, Ridolfini MP, Germanos S. Intraductal papillary mucinous neoplasms of the pancreas. Eur J Surg Oncol. 2007;33(6):678–84.PubMedView ArticleGoogle Scholar
- Anand N, Sampath K, Wu BU. Cyst features and risk of malignancy in intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis. Clin Gastroenterol Hepatol. 2013;11(8):913–21. quiz e59-60.PubMedView ArticleGoogle Scholar
- Tanaka M, Chari S, Adsay V, Fernandez-del Castillo C, Falconi M, Shimizu M, et al. International consensus guidelines for management of intraductal papillary mucinous neoplasms and mucinous cystic neoplasms of the pancreas. Pancreatology. 2006;6(1–2):17–32.PubMedView ArticleGoogle Scholar
- Tanaka M, Fernandez-del Castillo C, Adsay V, Chari S, Falconi M, Jang JY, et al. International consensus guidelines 2012 for the management of IPMN and MCN of the pancreas. Pancreatology. 2012;12(3):183–97.PubMedView ArticleGoogle Scholar
- Fritz S, Klauss M, Bergmann F, Strobel O, Schneider L, Werner J, et al. Pancreatic main-duct involvement in branch-duct IPMNs: an underestimated risk. Ann Surg. 2014;260(5):848–56.PubMedView ArticleGoogle Scholar
- Tanaka M. Controversies in the management of pancreatic IPMN. Nat Rev Gastroenterol Hepatol. 2011;8(1):56–60.PubMedView ArticleGoogle Scholar
- Talukdar R, Nageshwar RD. Treatment of pancreatic cystic neoplasm: surgery or conservative? Clin Gastroenterol Hepatol. 2014;12(1):145–51.PubMedView ArticleGoogle Scholar
- Miller JR, Meyer JE, Waters JA, Al-Haddad M, Dewitt J, Sherman S, et al. Outcome of the pancreatic remnant following segmental pancreatectomy for non-invasive intraductal papillary mucinous neoplasm. HPB (Oxford). 2011;13(11):759–66.View ArticleGoogle Scholar
- Fujii T, Kanda M, Kodera Y, Nagai S, Sahin TT, Kanzaki A, et al. Comparison of pancreatic head resection with segmental duodenectomy and pylorus-preserving pancreatoduodenectomy for benign and low-grade malignant neoplasms of the pancreatic head. Pancreas. 2011;40(8):1258–63.PubMedView ArticleGoogle Scholar
- Nakao A, Fernandez-Cruz L. Pancreatic head resection with segmental duodenectomy: safety and long-term results. Ann Surg. 2007;246(6):923–8. discussion 9–31.PubMedView ArticleGoogle Scholar
- Place TL, Nau P, Mezhir JJ. Minimally invasive pancreatectomy for cancer: a critical review of the current literature. J Gastrointest Surg. 2014;19(2):375–86.PubMedView ArticleGoogle Scholar
- Nakagohri T, Kinoshita T, Konishi M, Takahashi S, Gotohda N, Kobayashi S, et al. Inferior head resection of the pancreas for intraductal papillary mucinous neoplasms. J Hepatobiliary Pancreat Sci. 2010;17(6):798–802.PubMedView ArticleGoogle Scholar
- Takada T. Ventral pancreatectomy: resection of the ventral segment of the pancreas. J Hepatobiliary Pancreat Surg. 1993;1(1):36–40.View ArticleGoogle Scholar
- Ohno Y, Kanematsu T. Annular pancreas causing localized recurrent pancreatitis in a child: report of a case. Surg Today. 2008;38(11):1052–5.PubMedView ArticleGoogle Scholar
- Ladd AP, Madura JA. Congenital duodenal anomalies in the adult. Arch Surg. 2001;136(5):576–84.PubMedView ArticleGoogle Scholar