Tagai Noriyuki, Goi Takanori, Koneri Kenji, Murakami Makoto
Department of Surgery 1, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-Cho, Yoshida-gun, Fukui, 910-1193, Japan.
J Med Case Rep. 2024 Dec 20;18(1):615. doi: 10.1186/s13256-024-04982-6.
Type 2 autoimmune pancreatitis is characterized by multiple or segmental strictures of the main pancreatic duct without upstream dilatation. We encountered a case of mass-forming type 2 autoimmune pancreatitis with upstream main pancreatic duct dilatation that was difficult to diagnose preoperatively using endoscopic ultrasound sonography-guided fine-needle aspiration cytology.
A 58-year-old Japanese man presented with recurrent acute pancreatitis secondary to a 10-mm pancreatic head tumor. The tumor compressed the main pancreatic duct, thereby dilating the upstream main pancreatic duct. The serum immunoglobin G4 levels were within normal limits. Endoscopic ultrasound sonography-guided fine-needle aspiration cytology was performed twice. However, few degenerative atypical cells were observed, resulting in an indeterminate diagnosis. The patient underwent pancreaticoduodenectomy, and pathological findings revealed duct-centric pancreatitis with neutrophilic infiltration of the interlobular pancreatic ductal epithelium. Immunoglobin G4-positive cells were not detected. The patient was diagnosed with type 2 autoimmune pancreatitis.
Mass-forming type 2 autoimmune pancreatitis can present with main pancreatic duct strictures and upstream dilatation. Although endoscopic ultrasound sonography-guided fine-needle aspiration cytology is useful for the diagnosis of solid pancreatic masses, preoperative diagnosis of type 2 autoimmune pancreatitis remains challenging. Further studies should be conducted to determine whether "hidden" type 2 autoimmune pancreatitis may be more frequently present and to improve the accuracy of the diagnosis of type 2 autoimmune pancreatitis.
2型自身免疫性胰腺炎的特征是主胰管出现多处或节段性狭窄，且无上游扩张。我们遇到一例肿块型2型自身免疫性胰腺炎，其主胰管上游扩张，术前使用内镜超声引导下细针穿刺细胞学检查难以诊断。
一名58岁的日本男性因10毫米胰头肿瘤继发复发性急性胰腺炎就诊。肿瘤压迫主胰管，导致主胰管上游扩张。血清免疫球蛋白G4水平在正常范围内。内镜超声引导下细针穿刺细胞学检查进行了两次。然而，仅观察到少量退变的非典型细胞，诊断不明确。患者接受了胰十二指肠切除术，病理检查发现以导管为中心的胰腺炎，小叶间胰管上皮有中性粒细胞浸润。未检测到免疫球蛋白G4阳性细胞。患者被诊断为2型自身免疫性胰腺炎。
肿块型2型自身免疫性胰腺炎可表现为主胰管狭窄和上游扩张。虽然内镜超声引导下细针穿刺细胞学检查对实性胰腺肿块的诊断有用，但2型自身免疫性胰腺炎的术前诊断仍然具有挑战性。应进一步开展研究，以确定“隐匿性”2型自身免疫性胰腺炎是否可能更常见，并提高2型自身免疫性胰腺炎的诊断准确性。
