十二指肠异位胰腺的临床特点及影像学误诊分析

Clinical characteristics and imaging misdiagnosis analysis of duodenal heterotopic pancreas

目的:探讨十二指肠异位胰腺的临床特点和CT表现。方法:回顾性分析影像学误诊但经病理证实的10例十二指肠异位胰腺患者的临床及影像资料,分析患者的主要临床表现、病变部位、病变形态特征、长径(LD)与短径(SD)比值范围,以及病灶与正常胰腺组织CT值的差异性。结果:主要临床表现:反复腹痛伴腹胀5例,黑便3例,黄疸2例;影像学表现:2例病灶未见显影,分别位于十二指肠乳头部和Vater壶腹;8例可见病灶均表现为位于Vater壶腹以上的结节性病灶,其中6例基底部呈山田Ⅱ型,7例腔内生长,5例密度均匀且边界清晰;8例可见病灶LD/SD值:1.14~1.92,平均1.52±0.24,5例LD/SD>1.4;病灶实质区平扫及静脉期CT值稍低于同层正常胰腺组织(t=-3.41,-1.00,P<0.05),差值均数仅分别为(6.38±2.45)HU、(5.25±3.33)HU,肉眼观难以分辨;误诊情况:4例误诊为平滑肌瘤或炎性息肉,4例误诊为间质瘤;2例误诊为壶腹周围癌。结论:十二指肠异位胰腺影像学多表现为宽基底、腔内生长、边界清晰、密度均匀、强化方式及程度与正常胰腺基本一致的结节,但当病灶表现不典型(如边界不清、密度不均、未见显影)时易造成误诊。临床工作中加强对本病的认识,充分结合临床表现,有助于做出提示性诊断。

Objective： To analyze the clinical characteristics and CT findings of heterotopic pancreas in duodenum. Methods： The clinical and imaging data of 10 patients with heterotopic pancreas in duodenum were reviewed retrospectively,which were confirmed by pathology but misdiagnosed by imaging. Clinical manifestations, morphological characteristics, the ratio range between longitudinal diameter（LD） and short diameter（SD） and the differences in CT values between normal pancreas and the lesions were analyzed. Results： Main clinical manifestations in these patients were as follows： recurrent abdominal pain and distension in 5 cases, melena in 3 cases and jaundice in 2 cases. In terms of imaging findings, two lesions were not shown on CT which were located in duodenal papilla or Vater ampulla, and eight cases showed nodular lesions which were all above Vater ampulla. Six cases were Yamada type Ⅱ, seven cases were intracavitary, five cases showed clear margin and homogeneous density. The LD/SD values in eight cases were from 1.14 to 1.92, which was 1.52±0.24 in an average, LD/SD were above 1.4 in 5 cases. In the plain phase and the portal vein phase, CT values of the lesions were slightly lower than normal pancreas（t=-3.41, -1.00, P〈0.05）, the mean differences were only （6.38±2.45） HU and （5.25±3.33） HU respectively, which were indistinguishable to naked eyes. In the aspect of misdiagnoses, four cases were misdiagnosed as leiomyomas or inflammatory polyps, four cases as gastrointestinal stromal tumors（GIST）, two cases as periampullary carcinomas. Conclusion： The imaging findings of heterotopic pancreas in duodenum are nodules with broad base, intracavitary distribution, clear margin, homogeneous density and the similar characteristics of enhancement to normal pancreas. However, atypical imaging findings may lead to misdiagnosis. Further understanding of the disease as well as fully combining with clinical features are of vital importance for diagnosis.