Tools
Annular Pancreas
Introduction
Annular pancreas is a rare congenital anomaly that is present in less than 1% of the population and is characterized by partial or complete circumferential encasement of the second part of the duodenum by a band of pancreatic tissue during embryogenesis.[1][2] This band is usually located above the papilla of Vater in approximately 85% of diagnosed cases.[3] Results from older studies have reported a prevalence of annular pancreas of 3 of 20,000 autopsies and 3 of 24,519 surgical cases.[4][5] With the advent of newer, more advanced diagnostic modalities, this condition is increasingly recognized. Many individuals with this anomaly remain asymptomatic throughout their lifetime and are often diagnosed incidentally on imaging or during autopsies. However, a subset of patients with annular pancreas may present with clinical manifestations early in life or in adulthood, typically between 20 and 50 years of age.[6][7][8]
Based on the morphologic distribution of pancreatic tissue, annular pancreas has been classified into a complete or incomplete type. Complete type annular pancreas shows pancreatic parenchyma or annular duct completely encircling the second part of the duodenum, confirmed by macroscopic inspection, and incomplete type annular pancreas demonstrates partial circumferential encasement of the duodenum by pancreatic tissue, confirmed by endoscopic retrograde cholangiopancreatography (ERCP) or surgical evaluation.[9] The annular pancreatic duct (APD) commonly drains into the central pancreatic duct (MPD). Still, it can communicate with the intrapancreatic common bile duct (CBD), the duct of Santorini, or the duct of Wirsung.[10] Yogi et al classified annular pancreas into 6 subtypes, with type I demonstrating communication of APD with the duct of Wirsung and type II showing the duodenum encircled by MPD. Types I and II are the most common subtypes, with the other 4 subtypes less frequently encountered and corresponding to the APD communicating with the duct of Santorini or the CBD.[11]
Etiology
Register For Free And Read The Full Article
Search engine and full access to all medical articles- 10 free questions in your specialty
- Free CME/CE Activities
- Free daily question in your email
- Save favorite articles to your dashboard
- Emails offering discounts
Learn more about a Subscription to StatPearls Point-of-Care
Etiology
Given the rarity of this congenital condition, the precise etiology of annular pancreas development is not well defined, but it is considered an embryopathy.[6] During the first 4 to 8 weeks of embryonic development, the pancreas normally develops following rotation and fusion of the dorsal and ventral pancreatic buds as a result of the expansion of the duodenum. The ventral bud develops into the inferior part of the head and the uncinate process of the pancreas, while the dorsal bud develops into the body and tail of the pancreas.[9][12] The development of annular pancreas is proposed to be a migration anomaly resulting from the failure of the ventral bud to rotate and extend to encase the second portion of the duodenum either partially or completely.[9][12]
Several theories, some dating back to the 1900s, have been proposed to explain the formation of an annular pancreas, but none have gained predominance. However, immunohistochemistry studies have shown that the annular pancreas arises from the ventral pancreatic anlage.[8] Although not well studied, the role of genetic factors in this anomaly has been linked to isolated case reports of familial annular pancreas and to overexpression of the ventral-specific gene transmembrane 4 superfamily member 3 (tm4sf3).[13]
Epidemiology
The true prevalence of annular pancreas is currently unknown owing to the rarity and infrequent reporting of this congenital anomaly. Before the availability of contemporary imaging, this anomaly was noted incidentally in 3 of 20,000 autopsies and in 3 of 24,519 individuals who underwent abdominal surgeries.[4][5] With the availability of novel imaging modalities, the prevalence of annular pancreas has increased marginally to approximately 1 in 1000 cases.[14][15][16] Annular pancreas affects both sexes with a slight male preponderance, which has been a contentious issue.[17][18] Annular pancreas accounts for 30% of congenital duodenal obstructions in newborns.[19]
Pathophysiology
The pathophysiology of annular pancreas is explained by the direct impact of the migratory defect during embryogenesis. Duodenal obstruction is secondary to a mechanical defect, which can be extrinsic from the encasement of the duodenum or intrinsic from scarring, stenosis, or the presence of duodenal webs. The pathogenesis of pancreatitis in annular pancreas is unclear. Pancreatitis, when it occurs, is usually confined to the annulus and the adjoining pancreatic head, sparing the body and tail of the gland, which is likely secondary to fibrosis that prevents pancreatic secretions from passing through the annular duct and increases the intrinsic susceptibility of the annular pancreatic tissue to damage.[20][21][22] Peptic ulcer disease may be related to gastric stasis and antral overdistension with resulting hypergastrinemia.[8][23] Biliary ductal dilation is likely due to the progression of chronic pancreatitis, leading to fibrosis or ductal compression by the annular gland.[9]
Histopathology
Microscopic examination of the annular pancreatic tissue demonstrates the presence of many pancreatic polypeptide cells of the ventral pancreatic anlage arranged in irregularly shaped islets.[24] Histologically, annular pancreas has been classified into 2 types: intramural and extramural, on the basis of pancreatic tissue within the duodenal wall. The extramural type exhibits the presence of a ventral pancreatic duct encircling the duodenum, and the intramural type reveals the presence of pancreatic tissue woven into the duodenal wall with evidence of small ducts draining into the duodenum.[23]
History and Physical
Clinical manifestations of annular pancreas can occur at any age, from infancy to adulthood, and, given its bimodal age distribution, the age of presentation and the degree of duodenal constriction are key factors.[9] Infants with annular pancreas associated with significant duodenal constriction present with nonbilious vomiting, bloating, and feeding intolerance. Other infants with minimal constriction or nonexistent constriction can remain asymptomatic lifelong, and a small fraction can become symptomatic, usually between the third and sixth decade of life, presenting with symptoms of abdominal pain, duodenal obstruction, and pancreatitis, as evidenced by the review of a large case series cohort by SJS Nagpal et al.[1] The other, less common manifestations of annular pancreas in adulthood are peptic ulcer disease and biliary obstruction.[25][26]
The association of chromosomal abnormalities in annular pancreas is well known, with trisomy 21 being the most frequently detected anomaly.[27] Many infants with annular pancreas also have various other associated congenital anomalies, including malrotation, tracheoesophageal fistula, esophageal atresia, duodenal atresia, renal anomalies, duodenal diverticulum, pancreas divisum, biliary atresia, anorectal malformations, and congenital heart disease.[6][26][27] In adults with annular pancreas, the most common associated anomalies were pancreatic divisum, malrotation, duodenal webs, and Schatzki ring.[27]
Evaluation
No biochemical or genetic test is available specifically for annular pancreas. The diagnosis of annular pancreas is radiologic and usually made incidentally or on the evaluation of clinical manifestations of annular pancreas. The diagnosis of annular pancreas can be made prenatally, preoperatively, or intraoperatively using a range of noninvasive and invasive diagnostic techniques. Prenatally, an annular pancreas can be diagnosed by prenatal ultrasonography.[27][28] In infants presenting with signs of intestinal obstruction, the diagnosis can be made by ultrasonography or plain abdominal radiographs, which demonstrate the classic “double bubble sign.” However, this is nonspecific for annular pancreas.[29][30]
Newer ultrasonographic techniques incorporating upper gastrointestinal saline contrast have been used to improve the accuracy of diagnosing this rare congenital anomaly.[31][32] In adults, the diagnosis is usually made by computerized tomography (CT) imaging or magnetic resonance imaging. A large retrospective case series by SJS Nagpal et al showed that a significant number of patients were diagnosed solely by CT imaging.[1] Other imaging techniques that aid in diagnosing annular pancreas include magnetic resonance cholangiopancreatography, ERCP, and endoscopic ultrasonography.[33][34]
Sandrasegaran et al showed that complete encasement of the duodenum by pancreatic tissue is not essential for diagnosing annular pancreas.[9] Newer imaging techniques, including positron emission tomography/CT with the radiotracers C-11 choline and F-18 fluciclovine, have demonstrated the diagnosis of annular pancreas.[35] Despite many advances in diagnostic techniques, the gold standard test for diagnosing annular pancreas remains laparotomy with a thorough gross examination of the duodenum and the head of the pancreas.[27]
Treatment / Management
Best-practice guidelines for the management of annular pancreas are lacking, and treatment is tailored to each patient's symptoms and complications.[30] Asymptomatic individuals without signs or symptoms of annular pancreas can be observed closely without intervention.[6] Patients presenting with symptoms of acute pancreatitis should be managed with supportive care. Recurrent disabling attacks of acute-on-chronic pancreatitis can be considered for a pylorus-preserving Whipple procedure on a case-by-case basis.[1] (B3)
Division of the pancreatic annulus is not advised due to the increased incidence of postoperative complications such as pancreatitis, pancreatic fistulas, and duodenal stenosis.[30] Management of symptomatic cases with duodenal obstruction secondary to annular pancreas is purely surgical, with surgical bypass procedures such as gastrojejunostomy, duodenoduodenostomy, or duodenojejunostomy in adults and children.[18][30] In contrast to children undergoing duodenal bypass procedures, Zyromski et al highlighted the complex pancreaticobiliary pathology associated with annular pancreas in the adult population by describing that 20% of adults in their study group requiring surgical intervention underwent complex pancreaticobiliary surgical procedures, which included pancreaticoduodenectomy, lateral pancreatojejunostomy, biliary/pancreatic sphincteroplasty, and bypass of the biliary system.[27](B3)
Differential Diagnosis
As the clinical manifestations of annular pancreas exhibit a bimodal age distribution, presenting either early during infancy or adulthood, the differential diagnosis of this anomaly is also based on the age of presentation. Infants commonly present with duodenal obstruction and the classic "double bubble sign" on imaging; the differential diagnosis can be classified into intrinsic or extrinsic causes.[29][36]
Intrinsic Causes
- Duodenal atresia
- Duodenal stenosis
- Paraduodenal hernias
- Meckel diverticulum
- Duodenal webs (critical intrinsic causes that need to be considered)
Extrinsic Causes
- Malrotation of the gut
- Midgut volvulus
Miscellaneous Causes
Prognosis
The prognosis of annular pancreas in children is excellent, with increased overall survival rates, despite the presence of associated congenital malformations and chromosomal anomalies.[39] This has been attributed to improved neonatal care, nutritional management, early detection, and management of associated anomalies.[26] The prognosis of annular pancreas in adults is favorable if it is not complicated by underlying malignancy.
Complications
Complications of annular pancreas are secondary to the mechanical migratory effect of the pancreatic anlage and include:
Deterrence and Patient Education
Deterrence in annular pancreas focuses on early recognition rather than actual prevention, as this congenital anomaly results from incomplete rotation of the ventral pancreatic bud and cannot be avoided through behavioral or environmental modifications. Annular pancreas involves a ring of pancreatic tissue encasing the duodenum and was historically identified during surgery or autopsy, but modern imaging has led to more frequent diagnosis. Although many patients remain asymptomatic, infants may present with duodenal obstruction—manifesting as bilious vomiting or feeding intolerance—while adults may develop abdominal pain, peptic ulcer disease, or pancreatitis. The condition is also associated with chromosomal abnormalities, most commonly trisomy 21. Prompt recognition of these presentations allows early imaging, surgical evaluation, and intervention before complications such as dehydration, malnutrition, or recurrent pancreatitis progress.
Patient and family education is central to improving outcomes, reducing anxiety, and supporting timely care. Families should receive clear explanations of the anatomy, associated conditions, and the rationale for surgical management—typically duodenal bypass procedures such as gastrojejunostomy, duodenoduodenostomy, or duodenojejunostomy in children and adults. Education should also address postoperative expectations, including changes in feeding, monitoring for vomiting, abdominal distention, or weight loss, and recognizing signs of obstruction or infection. Adults benefit from guidance on symptom monitoring, dietary strategies during pancreatitis episodes, and when to seek urgent care. Involving surgeons, pediatricians, nutritionists, and genetic counselors when indicated enhances communication, sets realistic expectations, and supports safe recovery and long-term outcomes.
Enhancing Healthcare Team Outcomes
Annular pancreas is a rare congenital anomaly characterized by partial or complete encasement of the duodenum by pancreatic tissue. Although traditionally viewed as a disorder of infancy, evidence shows it occurs with nearly equal frequency in adults and children. Symptoms vary depending on the degree of duodenal constriction and may include duodenal obstruction, abdominal pain, and pancreatitis. Because standardized management guidelines are lacking, care must be individualized based on symptom severity and associated complications.[30] Early detection through advanced imaging and awareness of concurrent anomalies is essential to reduce morbidity and mortality.
Optimal management requires a coordinated interprofessional approach involving neonatologists, gastroenterologists, surgeons, radiologists, nurses, dietitians, and pharmacists.[27][44] Effective communication ensures timely diagnosis, nutritional optimization, and surgical planning, particularly when chromosomal or structural anomalies are present. Clinicians must develop diagnostic skills using imaging modalities such as computed tomography and magnetic resonance imaging, apply evidence-based interventions, and coordinate follow-up to monitor adults at risk for neoplasia. This collaborative, patient-centered strategy enhances safety, outcomes, and overall team performance.[27]
References
Nagpal SJS, Peeraphatdit T, Sannapaneni SK, Sharma A, Takahashi N, Kendrick ML, Majumder S, Vege SS. Clinical spectrum of adult patients with annular pancreas: Findings from a large single institution cohort. Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.]. 2019 Mar:19(2):290-295. doi: 10.1016/j.pan.2018.12.009. Epub 2019 Jan 3 [PubMed PMID: 30660391]
Cao J, Sha L, Wang J. Gastrointestinal: Annular pancreas: duodenal ampulla cancer. Journal of gastroenterology and hepatology. 2025 Jan:40(1):12-13. doi: 10.1111/jgh.16691. Epub 2024 Aug 27 [PubMed PMID: 39191436]
Benassai G, Perrotta S, Furino E, De Werra C, Aloia S, Del Giudice R, Amato B, Vigliotti G, Limite G, Quarto G. "Ductal adenocarcinoma in anular pancreas". International journal of surgery (London, England). 2015 Sep:21 Suppl 1():S95-7. doi: 10.1016/j.ijsu.2015.04.086. Epub 2015 Jun 25 [PubMed PMID: 26118607]
RAVITCH MM, WOODS AC Jr. Annular pancreas. Annals of surgery. 1950 Dec:132(6):1116-27 [PubMed PMID: 14790583]
THEODORIDES T. [ANNULAR PANCREAS]. Journal de chirurgie. 1964 Apr:87():445-62 [PubMed PMID: 14161588]
Nobukawa B, Otaka M, Suda K, Fujii H, Matsumoto Y, Miyano T. An annular pancreas derived from paired ventral pancreata, supporting Baldwin's hypothesis. Pancreas. 2000 May:20(4):408-10 [PubMed PMID: 10824697]
Level 3 (low-level) evidenceCai H, Wang X, Cai YQ, Li YB, Meng LW, Peng B. Laparoscopic Roux-en-Y duodenojejunostomy for annular pancreas in adults: case report and literature review. Annals of translational medicine. 2018 Jun:6(11):211. doi: 10.21037/atm.2018.05.13. Epub [PubMed PMID: 30023374]
Level 3 (low-level) evidenceDowsett JF, Rode J, Russell RC. Annular pancreas: a clinical, endoscopic, and immunohistochemical study. Gut. 1989 Jan:30(1):130-5 [PubMed PMID: 2920917]
Level 3 (low-level) evidenceSandrasegaran K, Patel A, Fogel EL, Zyromski NJ, Pitt HA. Annular pancreas in adults. AJR. American journal of roentgenology. 2009 Aug:193(2):455-60. doi: 10.2214/AJR.08.1596. Epub [PubMed PMID: 19620443]
Level 2 (mid-level) evidenceTürkvatan A, Erden A, Türkoğlu MA, Yener Ö. Congenital variants and anomalies of the pancreas and pancreatic duct: imaging by magnetic resonance cholangiopancreaticography and multidetector computed tomography. Korean journal of radiology. 2013 Nov-Dec:14(6):905-13. doi: 10.3348/kjr.2013.14.6.905. Epub 2013 Nov 5 [PubMed PMID: 24265565]
Yogi Y, Shibue T, Hashimoto S. Annular pancreas detected in adults, diagnosed by endoscopic retrograde cholangiopancreatography: report of four cases. Gastroenterologia Japonica. 1987 Feb:22(1):92-9 [PubMed PMID: 3569755]
Level 3 (low-level) evidenceAlahmadi R, Almuhammadi S. Annular pancreas: a cause of gastric outlet obstruction in a 20-year-old patient. The American journal of case reports. 2014 Oct 9:15():437-40. doi: 10.12659/AJCR.891041. Epub 2014 Oct 9 [PubMed PMID: 25300027]
Level 3 (low-level) evidenceEtienne D, John A, Menias CO, Ward R, Tubbs RS, Loukas M. Annular pancreas: a review of its molecular embryology, genetic basis and clinical considerations. Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 2012 Sep:194(5):422-8. doi: 10.1016/j.aanat.2012.04.006. Epub 2012 May 17 [PubMed PMID: 22694842]
Chevillotte G, Sahel J, Raillat A, Sarles H. Annular pancreas. Report of one case associated with acute pancreatitis and diagnosed by endoscopic retrograde pancreatography. Digestive diseases and sciences. 1984 Jan:29(1):75-7 [PubMed PMID: 6692735]
Level 3 (low-level) evidenceGlazer GM, Margulis AR. Annular pancreas: etiology and diagnosis using endoscopic retrograde cholangiopancreatography. Radiology. 1979 Nov:133(2):303-6 [PubMed PMID: 493513]
Level 3 (low-level) evidenceGromski MA, Lehman GA, Zyromski NJ, Watkins JL, El Hajj II, Tan D, McHenry L, Easler JJ, Tirkes T, Sherman S, Fogel EL. Annular pancreas: endoscopic and pancreatographic findings from a tertiary referral ERCP center. Gastrointestinal endoscopy. 2019 Feb:89(2):322-328. doi: 10.1016/j.gie.2018.09.008. Epub 2018 Sep 18 [PubMed PMID: 30240880]
Kiernan PD, ReMine SG, Kiernan PC, ReMine WH. Annular pancreas: May Clinic experience from 1957 to 1976 with review of the literature. Archives of surgery (Chicago, Ill. : 1960). 1980 Jan:115(1):46-50 [PubMed PMID: 7350885]
Level 2 (mid-level) evidenceHuddleston VS, Lippuner V, Dyer AW. Annular Pancreas in an Adult Presenting with Acute Pancreatitis. Journal of radiology case reports. 2018 Oct:12(10):11-16. doi: 10.3941/jrcr.v12i10.3461. Epub 2018 Oct 31 [PubMed PMID: 30651906]
Level 3 (low-level) evidencePijpers AGH, Eeftinck Schattenkerk LD, Straver B, Zwijnenburg PJG, Broers CJM, Van Heurn ELW, Gorter RR, Derikx JPM. The Incidence of Associated Anomalies in Children with Congenital Duodenal Obstruction-A Retrospective Cohort Study of 112 Patients. Children (Basel, Switzerland). 2022 Nov 24:9(12):. doi: 10.3390/children9121814. Epub 2022 Nov 24 [PubMed PMID: 36553258]
Level 2 (mid-level) evidenceItoh Y, Hada T, Terano A, Itai Y, Harada T. Pancreatitis in the annulus of annular pancreas demonstrated by the combined use of computed tomography and endoscopic retrograde cholangiopancreatography. The American journal of gastroenterology. 1989 Aug:84(8):961-4 [PubMed PMID: 2756989]
Level 3 (low-level) evidenceDREY NW. Symptomatic annular pancreas in the adult. Annals of internal medicine. 1957 Apr:46(4):750-72 [PubMed PMID: 13411884]
Jarry J, Wagner T, Rault A, Sa Cunha A, Collet D. Annular pancreas: a rare cause of acute pancreatitis. JOP : Journal of the pancreas. 2011 Mar 9:12(2):155-7 [PubMed PMID: 21386643]
Level 3 (low-level) evidenceJohnston DW. Annular pancreas: a new classification and clinical observations. Canadian journal of surgery. Journal canadien de chirurgie. 1978 May:21(3):241-4 [PubMed PMID: 647515]
Level 3 (low-level) evidenceSuda K. Immunohistochemical and gross dissection studies of annular pancreas. Acta pathologica japonica. 1990 Jul:40(7):505-8 [PubMed PMID: 2220397]
SILVIS RS. Annular pancreas. Annals of surgery. 1952 Feb:135(2):278-83 [PubMed PMID: 14903856]
Yigiter M, Yildiz A, Firinci B, Yalcin O, Oral A, Salman AB. Annular pancreas in children: a decade of experience. The Eurasian journal of medicine. 2010 Dec:42(3):116-9. doi: 10.5152/eajm.2010.33. Epub [PubMed PMID: 25610139]
Zyromski NJ, Sandoval JA, Pitt HA, Ladd AP, Fogel EL, Mattar WE, Sandrasegaran K, Amrhein DW, Rescorla FJ, Howard TJ, Lillemoe KD, Grosfeld JL. Annular pancreas: dramatic differences between children and adults. Journal of the American College of Surgeons. 2008 May:206(5):1019-25; discussion 1025-7. doi: 10.1016/j.jamcollsurg.2007.12.009. Epub 2008 Feb 11 [PubMed PMID: 18471747]
Dankovcik R, Muranska S, Kucera E, Jirasek JE, Feyereisl J, Sudak M, Dudas M. Prenatal three-dimensional sonographic findings associated with annular pancreas. Fetal diagnosis and therapy. 2010:27(1):57-60. doi: 10.1159/000262277. Epub 2009 Nov 25 [PubMed PMID: 19940446]
Level 3 (low-level) evidenceWhittingham-Jones PM, Riaz AA, Clayton G, Thompson HH. Annular pancreas - a rare cause of gastric obstruction in an 82-year-old patient. Annals of the Royal College of Surgeons of England. 2005 Jan:87(1):W13-5 [PubMed PMID: 16790121]
Rondelli F, Bugiantella W, Stella P, Boni M, Mariani E, Crusco F, Sanguinetti A, Polistena A, Avenia N. Symptomatic annular pancreas in adult: Report of two different presentations and treatments and review of the literature. International journal of surgery case reports. 2016:20S(Suppl):21-4. doi: 10.1016/j.ijscr.2016.02.001. Epub 2016 Feb 3 [PubMed PMID: 26867720]
Level 3 (low-level) evidenceBoviatsi D, Zoumpoulis G, Koutrouveli E, Vakaki M, Marantos A, Shihada A, Samolis A, Chrysikos D, Filippou D, Troupis T. Annular Pancreas: Insights Into the Diagnosis of a Rare Anatomical Malformation in Pediatric Patients. Cureus. 2025 Jun:17(6):e85702. doi: 10.7759/cureus.85702. Epub 2025 Jun 10 [PubMed PMID: 40551727]
Yang B, He F, He Q, Wang Z, Fang Q, Zhong W, Wang H. Diagnostic value of the acute angle between the prestenotic and poststenotic duodenum in neonatal annular pancreas. European radiology. 2019 Jun:29(6):2902-2909. doi: 10.1007/s00330-018-5922-0. Epub 2019 Jan 7 [PubMed PMID: 30617479]
Reinhart RD, Brown JJ, Foglia RP, Aliperti G. MR imaging of annular pancreas. Abdominal imaging. 1994 Jul-Aug:19(4):301-3 [PubMed PMID: 8075549]
Level 3 (low-level) evidenceDharmsathaphorn K, Burrell M, Dobbins J. Diagnosis of annular pancreas with endoscopic retrograde cholangiopancreatography. Gastroenterology. 1979 Nov:77(5):1109-14 [PubMed PMID: 488638]
Level 3 (low-level) evidenceNguyen BD. C-11 Choline and F-18 Fluciclovine PET/CT demonstration of annular pancreas. Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver. 2018 Aug:50(8):853. doi: 10.1016/j.dld.2018.03.018. Epub 2018 Mar 20 [PubMed PMID: 29631936]
Traubici J. The double bubble sign. Radiology. 2001 Aug:220(2):463-4 [PubMed PMID: 11477252]
Adedeji OA, Trescoli-Serrano C, Garcia-Zarco M. Primary duodenal carcinoma. Postgraduate medical journal. 1995 Jun:71(836):354-8 [PubMed PMID: 7644397]
Level 2 (mid-level) evidenceWani AA, Maqsood S, Lala P, Wani S. Annular pancreas in adults: a report of two cases and review of literature. JOP : Journal of the pancreas. 2013 May 10:14(3):277-9. doi: 10.6092/1590-8577/1454. Epub 2013 May 10 [PubMed PMID: 23669479]
Level 3 (low-level) evidenceJimenez JC, Emil S, Podnos Y, Nguyen N. Annular pancreas in children: a recent decade's experience. Journal of pediatric surgery. 2004 Nov:39(11):1654-7 [PubMed PMID: 15547829]
Level 2 (mid-level) evidenceYakoubi C, Atri S, Maghrebi H, Kacem MJ. Annular pancreas. The British journal of surgery. 2022 Sep 9:109(10):1012. doi: 10.1093/bjs/znac167. Epub [PubMed PMID: 36084336]
Boateng S, Heymann G, Mejia F, Lerner BA, Loeser C. Annular Pancreas Causing Gastric Diverticulum in a 29-Year-Old Man: A Rare Complication of an Uncommon Condition. ACG case reports journal. 2025 Apr:12(4):e01667. doi: 10.14309/crj.0000000000001667. Epub 2025 Apr 7 [PubMed PMID: 40201220]
Level 3 (low-level) evidenceJha S, Luitel S, Kushwaha N, Singh S, Jha SK. "Partial Annular Pancreas Causing Obstruction of the First Part of the Duodenum: An Exceedingly Rare Conundrum-A Rare Case Report and Comprehensive Literature Review". Clinical case reports. 2025 Jul:13(7):e70614. doi: 10.1002/ccr3.70614. Epub 2025 Jul 9 [PubMed PMID: 40642593]
Level 3 (low-level) evidenceKumar V, Avudaiappan M, Sharma PK, Gupta V. Annular pancreas in adulthood: Two compelling cases, including one with pyloric stenosis and chronic pancreatitis. Medical journal, Armed Forces India. 2025 Jul-Aug:81(4):470-473. doi: 10.1016/j.mjafi.2023.12.012. Epub 2024 Feb 13 [PubMed PMID: 40697683]
Level 3 (low-level) evidenceMortelé KJ, Rocha TC, Streeter JL, Taylor AJ. Multimodality imaging of pancreatic and biliary congenital anomalies. Radiographics : a review publication of the Radiological Society of North America, Inc. 2006 May-Jun:26(3):715-31 [PubMed PMID: 16702450]