Abstract
The present case involved a 76-year-old man with a cystic mass in the head of his pancreas. The cystic lesion, which measured 17.7 × 9.8 mm, was first detected by ultrasonography (US) at the age of 72 years. Follow-up endoscopic ultrasonography (EUS) performed at 4 years after the lesion had first been detected revealed a mural nodule measuring 14.0 × 8.4 mm in the cyst. Endoscopic retrograde pancreatography (ERP) imaging revealed that the main pancreatic duct was in communication with the cyst and that there was no irregular narrowing of the main pancreatic duct. On the basis of these results, the patient was diagnosed with an intraductal papillary mucinous neoplasm (IPMN), and stomach-preserving pancreaticoduodenectomy was performed. A histopathological examination revealed that the interior of the cystic part of the lesion was lined by a pancreatic ductal epithelium. A pathological examination of the nodular lesion detected storiform fibrosis, severe lymphoplasmacytic infiltration, and hyperplasia in the pancreatic duct epithelium together with a small amount of mucus. On immunohistological staining, the infiltrating lymphoplasmacytes were found to be positive for IgG4. Accordingly, the patient was diagnosed with focal autoimmune pancreatitis (AIP). In conclusion, we reported a case of focal AIP mimicking IPMN. This case showed neither enlargement of the pancreas nor irregular narrowing of the main pancreatic duct.
References
Sarles H, Sarles JC, Muratore R, Guien C. Chronic inflammatory sclerosis of the pancreas: an autonomous pancreatic disease? Am J Dig Dis. 1961;6:688–98.
Kwon S, Kim MH, Choi EK. The diagnostic criteria for autoimmune chronic pancreatitis: it is time to make a consensus. Pancreas. 2007;34:279–86.
Chari ST, Smyrk TC, Levy MJ, Topazian MD, Takahashi N, Zhang L, et al. Diagnosis of autoimmune pancreatitis: the Mayo Clinic experience. Clin Gastroenterol Hepatol. 2006;4:1010–6.
Nishimura T, Masaoka T, Suzuki H, Aiura K, Nagata H, Ishii H. Autoimmune pancreatitis with pseudocysts. J Gastroenterol. 2004;39:1005–10.
Muraki T, Hamano H, Ochi Y, Arakura N, Takayama M, Komatsu K, et al. Corticosteroid-responsive pancreatic cyst found in autoimmune pancreatitis. J Gastroenterol. 2005;40:761–6.
Welsch T, Kleeff J, Esposito I, Büchler MW, Friess H. Autoimmune pancreatitis associated with a large pancreatic pseudocyst. World J Gastroenterol. 2006;12:5904–6.
Kamisawa T, Anjiki H, Egawa N. Rapid disappearance of a pancreatic cyst after steroid therapy in a patient with autoimmune pancreatitis. Clin Gastroenterol Hepatol. 2008;6:e33–4.
Nakazawa T, Ohara H, Sano H, Ando T, Imai H, Takada H, et al. Difficulty in diagnosing autoimmune pancreatitis by imaging findings. Gastrointest Endosc. 2007;65:99–108.
Sohn JW, Cho CM, Jung MK, Park SY, Jeon SW. A case of autoimmune pancreatitis manifested by a pseudocyst and IgG4-associated cholangitis. Gut Liver. 2012;6:132–5.
Kawakami H, Kuwatani M, Shinada K, Yamato H, Hirano S, Kondo S, et al. Autoimmune pancreatitis associated with hemorrhagic pseudocysts: a case report and literature review. Intern Med. 2008;47:603–8.
Naitoh I, Nakazawa T, Notohara K, Miyabe K, Hayashi K, Shimizu S, et al. Intraductal papillary mucinous neoplasm associated with autoimmune pancreatitis. Pancreas. 2013;42:552–4.
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Nakaji, S., Hirata, N., Fujii, H. et al. A case of focal autoimmune pancreatitis (AIP) mimicking an intraductal papillary mucinous neoplasm (IPMN). Clin J Gastroenterol 6, 329–333 (2013). https://doi.org/10.1007/s12328-013-0392-z
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DOI: https://doi.org/10.1007/s12328-013-0392-z