{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T00:52:14Z","timestamp":1760057534496,"version":"build-2065373602"},"reference-count":33,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2025,2,12]],"date-time":"2025-02-12T00:00:00Z","timestamp":1739318400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Autoimmune pancreatitis (AIP) is a rare chronic pancreatitis subtype that often mimics pancreatic cancer due to the overlapping clinical and radiological features, posing significant diagnostic challenges. Similarly, distinguishing AIP from pancreatic neuroendocrine neoplasms (PanNENs), which present with nonspecific symptoms, adds complexity to clinical evaluations. We present the case of a 46-year-old male with recurrent acute idiopathic pancreatitis. Abdominal computed tomography (CT) revealed a 25 mm hypodense mass in the pancreatic tail with mild arterial contrast enhancement. Magnetic resonance imaging (MRI) showed the mass to be hypointense on T2-weighted sequences, with no diffusion restriction and an enhancement pattern akin to normal pancreatic tissue. The endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) was inconclusive. Gallium-68 DOTATATE positron emission tomography\u2013CT (Ga-68 DOTATATE PET-CT) showed an increased tracer uptake, leading to a distal pancreatectomy with a splenectomy. Histopathology demonstrated chronic sclerotic pancreatitis with inflammatory infiltrates. Elevated serum IgG4 levels confirmed the diagnosis of type 1 AIP Differentiating AIP from pancreatic malignancies, including PanNENs, is both critical and complex. This case highlights a misdiagnosis of PanNENs in a patient with focal AIP, where neuroendocrine hyperplasia and islet cell clusters within fibrotic areas mimicked PanNENs, even on Ga-68 PET-CT. The findings emphasize the potential for false positives with Ga-68 DOTATATE PET-CT and the importance of integrating clinical, radiological, and histological data for an accurate diagnosis.<\/jats:p>","DOI":"10.3390\/ijms26041536","type":"journal-article","created":{"date-parts":[[2025,2,12]],"date-time":"2025-02-12T04:37:04Z","timestamp":1739335024000},"page":"1536","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Autoimmune Pancreatitis Mimicking a Pancreatic Neuroendocrine Tumor: A Case Report with a Literature Review"],"prefix":"10.3390","volume":"26","author":[{"given":"Marianna","family":"Franchina","sequence":"first","affiliation":[{"name":"Division of Gastroenterology, ASST Papa Giovanni XXIII, 24127 Bergamo, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Liliana","family":"Dell\u2019Oro","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3214-8192","authenticated-orcid":false,"given":"Sara","family":"Massironi","sequence":"additional","affiliation":[{"name":"Department of Medicine and Surgery, Vita-Salute San Raffaele University, 20132 Milan, Italy"},{"name":"Istituti Ospedalieri Bergamaschi, 24040 Zingonia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"352","DOI":"10.1097\/MPA.0b013e3182142fd2","article-title":"International consensus diagnostic criteria for autoimmune pancreatitis: Guidelines of the International Association of Pancreatology","volume":"40","author":"Shimosegawa","year":"2011","journal-title":"Pancreas"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"462","DOI":"10.1007\/s00535-019-01658-7","article-title":"Nationwide epidemiological survey of autoimmune pancreatitis in Japan in 2016","volume":"55","author":"Masamune","year":"2020","journal-title":"J. Gastroenterol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1177\/2050640620934911","article-title":"European Guideline on IgG4-related digestive disease\u2014UEG and SGF evidence-based recommendations","volume":"8","author":"Beuers","year":"2020","journal-title":"United Eur. Gastroenterol. J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"817","DOI":"10.3748\/wjg.v30.i8.817","article-title":"Autoimmune pancreatitis: Cornerstones and future perspectives","volume":"30","author":"Gallo","year":"2024","journal-title":"World J. Gastroenterol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"417","DOI":"10.1097\/MOG.0000000000000655","article-title":"Autoimmune pancreatitis type 2","volume":"36","author":"Frulloni","year":"2020","journal-title":"Curr. Opin. Gastroenterol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1010","DOI":"10.1016\/j.cgh.2006.05.017","article-title":"Diagnosis of autoimmune pancreatitis: The Mayo Clinic experience","volume":"4","author":"Chari","year":"2006","journal-title":"Clin. Gastroenterol. Hepatol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"626","DOI":"10.1007\/s00535-006-1868-0","article-title":"Clinical diagnostic criteria of autoimmune pancreatitis: Revised proposal","volume":"41","author":"Okazaki","year":"2006","journal-title":"J. Gastroenterol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1007\/s00535-022-01857-9","article-title":"Amendment of the Japanese consensus guidelines for autoimmune pancreatitis, 2020","volume":"57","author":"Okazaki","year":"2022","journal-title":"J. Gastroenterol."},{"key":"ref_9","first-page":"185","article-title":"La maladie syst\u00e9mique \u00e0 IgG4, une cause rare de pancr\u00e9atite aig\u00fce s\u00e9v\u00e8re","volume":"139","author":"Bennis","year":"2020","journal-title":"Louvain Med."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"496","DOI":"10.1002\/ueg2.12237","article-title":"Unraveling the relationship between autoimmune pancreatitis type 2 and inflammatory bowel disease: Results from two centers and systematic review of the literature","volume":"10","author":"Nikolic","year":"2022","journal-title":"United Eur. Gastroenterol. J."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Tan, B., Zhang, B., and Chen, H. (2024). Gastroenteropancreatic neuroendocrine neoplasms: Epidemiology, genetics, and treatment. Front. Endocrinol., 15.","DOI":"10.3389\/fendo.2024.1424839"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/S1470-2045(07)70410-2","article-title":"Gastroenteropancreatic neuroendocrine tumours","volume":"9","author":"Modlin","year":"2008","journal-title":"Lancet Oncol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1335","DOI":"10.1001\/jamaoncol.2017.0589","article-title":"Trends in the Incidence, Prevalence, and Survival Outcomes in Patients With Neuroendocrine Tumors in the United States","volume":"3","author":"Dasari","year":"2017","journal-title":"JAMA Oncol."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Rossi, R.E., and Massironi, S. (2022). The Increasing Incidence of Neuroendocrine Neoplasms Worldwide: Current Knowledge and Open Issues. J. Clin. Med., 11.","DOI":"10.3390\/jcm11133794"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"e13343","DOI":"10.1111\/jne.13343","article-title":"European Neuroendocrine Tumour Society (ENETS) 2023 guidance paper for nonfunctioning pancreatic neuroendocrine tumours","volume":"35","author":"Denecke","year":"2023","journal-title":"J. Neuroendocrinol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1002\/cncr.29099","article-title":"Exploring the rising incidence of neuroendocrine tumors: A population-based analysis of epidemiology, metastatic presentation, and outcomes","volume":"121","author":"Hallet","year":"2015","journal-title":"Cancer"},{"key":"ref_17","first-page":"258","article-title":"Update on pancreatic neuroendocrine tumors","volume":"3","author":"McKenna","year":"2014","journal-title":"Gland Surg."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e13318","DOI":"10.1111\/jne.13318","article-title":"European Neuroendocrine Tumor Society 2023 guidance paper for functioning pancreatic neuroendocrine tumour syndromes","volume":"35","author":"Hofland","year":"2023","journal-title":"J. Neuroendocrinol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"312","DOI":"10.5732\/cjc.012.10295","article-title":"Pancreatic neuroendocrine tumors: Biology, diagnosis, and treatment","volume":"32","author":"Ro","year":"2013","journal-title":"Chin. J. Cancer"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1080\/17446651.2024.2320639","article-title":"The diagnostic challenges of functioning neuroendocrine tumors: Balancing accuracy, availability, and personalized care","volume":"19","author":"Massironi","year":"2024","journal-title":"Expert Rev. Endocrinol. Metab."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1080\/17446651.2024.2363537","article-title":"Improvements and future perspective in diagnostic tools for neuroendocrine neoplasms","volume":"19","author":"Massironi","year":"2024","journal-title":"Expert Rev. Endocrinol. Metab."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1016\/j.dld.2017.10.007","article-title":"Clinical impact of endoscopic ultrasonography on the management of neuroendocrine tumors: Lights and shadows","volume":"50","author":"Zilli","year":"2018","journal-title":"Dig. Liver Dis."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"275","DOI":"10.3748\/wjg.v23.i2.275","article-title":"Pancreatic neuroendocrine neoplasms: Magnetic resonance imaging features according to grade and stage","volume":"23","author":"Cingarlini","year":"2017","journal-title":"World J. Gastroenterol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"837","DOI":"10.1080\/14737140.2018.1496822","article-title":"Imaging of pancreatic neuroendocrine tumors: Recent advances, current status, and controversies","volume":"18","author":"Lee","year":"2018","journal-title":"Expert Rev. Anticancer. Ther."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1240","DOI":"10.1148\/rg.2020200025","article-title":"Pancreatic Neuroendocrine Neoplasms: 2020 Update on Pathologic and Imaging Findings and Classification","volume":"40","author":"Khanna","year":"2020","journal-title":"Radiographics"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"802","DOI":"10.1097\/RLU.0000000000002276","article-title":"68Ga PET Imaging in Patients With Neuroendocrine Tumors: A Systematic Review and Meta-analysis","volume":"43","author":"Singh","year":"2018","journal-title":"Clin. Nucl. Med."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1217","DOI":"10.1177\/0284185120958412","article-title":"Clinical value of (68)Ga-DOTA-SSTR PET\/CT in the diagnosis and detection of neuroendocrine tumors of unknown primary origin: A systematic review and meta-analysis","volume":"62","author":"Ma","year":"2021","journal-title":"Acta Radiol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"245","DOI":"10.3109\/00365521.2015.1083050","article-title":"Efficacy of endoscopic ultrasonography and endoscopic ultrasonography-guided fine-needle aspiration for the diagnosis and grading of pancreatic neuroendocrine tumors","volume":"51","author":"Fujimori","year":"2016","journal-title":"Scand. J. Gastroenterol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1159\/000336199","article-title":"Histopathologically proven autoimmune pancreatitis mimicking neuroendocrine tumor or pancreatic cancer","volume":"6","author":"Onda","year":"2012","journal-title":"Case Rep. Gastroenterol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"3479","DOI":"10.1007\/s10620-023-08056-3","article-title":"Autoimmune Pancreatitis Mimicking Neuroendocrine Tumor of Pancreas","volume":"68","author":"Sharma","year":"2023","journal-title":"Dig. Dis. Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"16","DOI":"10.5603\/NMR.2011.0004","article-title":"The diagnostic role of 68Ga-DOTATATE PET\/CT in the detection of neuroendocrine tumours","volume":"14","author":"Bryszewska","year":"2011","journal-title":"Nucl. Med. Rev. Cent East Eur."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1002\/kjm2.12641","article-title":"A rare case of type 1 autoimmune pancreatitis combined with a pancreatic neuroendocrine tumor","volume":"39","author":"Chang","year":"2023","journal-title":"Kaohsiung J. Med. Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"11","DOI":"10.3941\/jrcr.v15i1.3822","article-title":"Pancreatic Neuroendocrine Tumor presenting as a diffuse pancreatic enlargement, case report and review of literature","volume":"15","author":"Salahshour","year":"2021","journal-title":"J. Radiol. Case Rep."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/4\/1536\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T16:31:55Z","timestamp":1760027515000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/4\/1536"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,2,12]]},"references-count":33,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2025,2]]}},"alternative-id":["ijms26041536"],"URL":"https:\/\/doi.org\/10.3390\/ijms26041536","relation":{},"ISSN":["1422-0067"],"issn-type":[{"type":"electronic","value":"1422-0067"}],"subject":[],"published":{"date-parts":[[2025,2,12]]}}}