Matsubayashi Hiroyuki, Tomita Hideharu, Sugiura Teiichi, Sasaki Keiko, Inui Tetsuya, Takizawa Kohei, Yamaguchi Yuichiro, Ono Hiroyuki
Division of Endoscopy, Shizuoka Cancer Center, Shizuoka.
Intern Med. 2009;48(24):2087-91. doi: 10.2169/internalmedicine.48.2568.
Autoimmune pancreatitis (AIP) sometimes forms a pancreatic mass lesion, which is often difficult to distinguish from pancreatobiliary malignancy, however it generally responds to steroid therapy. A 70-year-old man was referred to our institute with the suspected diagnosis of pancreatic cancer due to a mass lesion detected at the pancreatic head. Various images demonstrated an ill-defined mass at the enlarged pancreatic head with focal narrowing of the main pancreatic duct. Serum antinuclear antibody (ANA) was negative (x40 dilution) on the onset. Forceps biopsy from the narrowed pancreaticobiliary duct and fine-needle aspiration biopsy under endoscopic ultrasonography (EUS-FNAB) ruled out pancreatobiliary malignancy. Steroid therapy was started at 40 mg per day but was not effective according to subsequent image analyses. Repeated EUS-FNA from the pancreatic mass was performed but was again negative for carcinoma. Seven months later, under steroid-off condition, still no response was recognized in the clinical image but the titer of serum ANA was increased to be positive (x80), satisfying the criteria of AIP in Japan (2006). Although very rare, this is a case meeting Japanese criteria of AIP after withdrawal of steroid without response to steroid in the clinical images, suggesting the necessity of careful follow-up.
自身免疫性胰腺炎（AIP）有时会形成胰腺肿块病变，这常常难以与胰胆恶性肿瘤区分开来，不过它通常对类固醇治疗有反应。一名70岁男性因胰头部发现肿块病变而被转诊至我院，疑似诊断为胰腺癌。各种影像学检查显示肿大的胰头部有边界不清的肿块，主胰管有局灶性狭窄。发病时血清抗核抗体（ANA）为阴性（40倍稀释）。经内镜超声引导下细针穿刺活检（EUS-FNAB）及经狭窄的胰胆管钳取活检排除了胰胆恶性肿瘤。开始每天40毫克的类固醇治疗，但后续影像学分析显示治疗无效。对胰腺肿块重复进行EUS-FNA检查，结果再次显示无癌细胞。7个月后，在停用类固醇的情况下，临床影像学仍无反应，但血清ANA滴度升高至阳性（80倍稀释），符合日本（2006年）AIP的诊断标准。尽管非常罕见，但这是一例在停用类固醇后符合日本AIP标准、临床影像学对类固醇治疗无反应的病例，提示需要仔细随访。
