MRI在十二指肠乳头腺瘤诊断中的价值

The Value of MR Imaging in Diagnosing Adenoma of the Major Duodenal Papilla

目的探讨MRI在十二指肠乳头腺瘤诊断及鉴别诊断中的价值。方法回顾性分析经病理证实的9例十二指肠乳头腺瘤的MRI特征。结果 9例肿瘤均表现为十二指肠乳头肿块。6例未恶变腺瘤,肿块呈类圆形,边界清楚,最大径10～27 mm,平均20 mm,呈渐进性轻中度强化,其中2例伴持续性周边明显环形强化; MRCP示胆总管下端向心性狭窄,胆管轻中度扩张为主,伴或不伴主胰管扩张; 4例Vater壶腹正常或轻度扩张,管壁正常或轻度增厚,渐进性强化。3例伴恶变腺瘤(2例伴局灶高级别内瘤变,1例伴局灶癌变)肿块,形态不规则,局部边界不清,最大径分别约20 mm、33 mm和47 mm,2例中等强化,1例明显强化; MRCP示胆总管下端截断性狭窄,上游胆管及胰管中重度扩张; Vater壶腹变形,显示不清,或管壁异常增厚,明显强化; 1例伴十二指肠壁受累。结论十二指肠乳头腺瘤的MRI表现有一定特征,当肿瘤形态不规则,体积较大,局部边界不清,胆总管末端截断性狭窄,Vater壶腹部和/或十二指肠壁受累时,应警惕肿瘤恶变可能。

Objective To explore the value of MRI in diagnosing adenoma of the major duodenal papilla. Methods The MRI and clinical features of 9 patients with histopathologically proven adenoma of the major duodenal papilla were retrospectively analyzed. Results Duodenal papilla mass was found in all the 9 cases. In the 6 uncancerated adenoma,the masses were round shaped and well-defined,with a diameter of 20 mm on average( ranged from 10 mm to 27 mm). The masses of the 6 cases showed mild to moderate progressive enhancement on dynamic contrast enhanced MRI( DCE-MRI),and 2 of the 6 masses showed continued obvious ring-like enhancement in the peripheral region. MRCP of the 6 cases showed a mild to moderate centripetal stenosis of the distant end of the common bile duct,and a mild to moderate dilatation of the upstream bile duct,with or without dilatation of the main pancreatic duct. The ampulla of Vater was normal or slightly dilated with or without mild thickening and progressive enhancement of its wall. In the 3 cancerated adenomata( 2 cases of villous tubular adenomas with focal high-grade epithelioid neoplasia,and 1 case of villous tubular adenomas with focal canceration),the masses were irregular and ill-defined,with a diameter of 20 mm,33 mm and 47 mm respectively. Moderate enhancement on DCE-MRI was found in 2 of the 3 masses and obvious enhancement in 1 mass. MRCP of the 3 cases showed a truncational stenosis of the distant end of the common bile duct,and a moderate to obvious dilatation of the upstream bile duct and the main pancreatic duct. The ampulla of Vater was deformed and inconclusive,or obvious wall thickening and enhancement. In 1 case,the adjacent duodenal wall also involved and thickened. Conclusion There are some MR imaging features for diagnosing adenoma of the major duodenal papilla. When the mass was large,irregular and ill-defined,with truncational stenosis of the distant end of the common bile duct,and the involvement of the ampulla of Vater or even duodenal wall,the possibility of canceration should be alerted.