胰腺腺泡细胞癌的CT和MRI表现

目的：分析胰腺腺泡细胞癌（ACC）的CT和MRI表现，提高对该病的认识。方法：回顾性分析经手术病理或穿刺活检证实的5例ACc患者的CT和MRI表现。5例均行CT平扫及增强扫描，2例行MRI检查。实验室检查甲胎蛋白（AFP）升高2例。结果：5例ACC中，4例单发，1例多发。2例位于胰头钩突部，2例位于胰尾部，1例多发肿瘤位于胰头及胰尾部。肿瘤平均最大径4．0cm。2例形态不规则，2例呈卵圆形，1例可见浅分叶。1例肿瘤可见完整包膜。4例肿瘤以实性成分为主，1例呈囊实性（中央囊性伴出血坏死）。1例伴钙化。5例肿瘤CT平扫均呈不均匀低密度，动脉期呈轻度不均匀强化，门脉期强化程度较动脉期略增高，但低于周围正常胰腺。2例MRI扫描示病灶在压脂T1WI上为均匀低信号，压脂T2WI上为不均匀略高信号。3例伴胰管扩张，其中1例伴低位胆管梗阻。结论：ACC可有完整包膜，可伴出血坏死和钙化，增强呈渐进性强化，较少引起胰胆管阻塞，实验室检查可提示AFP升高。

CT and MRI features of acinar cell carcinoma of the pancreas

Objective： To analyze the CT and MRI findings of acinar cell carcinoma （ACC） of the pancreas in order to determine the imaging significance of this rare condition. Methods：CT and MRI findings in 5 patients with histologically ver- ified pancreatic ACC were retrospectively reviewed. All cases underwent both p!ain and contrast enhanced CT scan. Two of them also had MRI scan. Reslllts：Of the 5 cases,four were of single lesion,two of them were found in the head of the pan- creas and the other two lesions were in the tail;one case was of multiple lesions found both in the head and the tail. The mean diameter was 4cm. Two lesions showed irregular shape,two had ovoid shape,and one was mildly lobulated. Only one lesion had a complete capsule. Four tumors were mainly solid and one was centrally cystic with hemorrhage. One mass had calcification inside. All five tumors showed relatively uneven lower density and moderate enhancement in arterial phase and slightly higher on portal venous phase, but still lower than normal surrounding pancreatic tissue. Two masses showed even low signal on fat-saturation T~WI and moderately uneven high signal on fat-saturation T2WI. Dilated pancreatic duct was seen in three cases and one of which was with low biliary obstruction. Serum ~-fetoprotein （AFP） was tested positively in two cases. Conclusion：Pancreatic ACC typically presents as a round-like mass which may have complete capsule and,some- times, hemorrhage, necrosis, significant central hypodentsity and internal calcifications. The mass usually shows progressive enhancement after contrast injection. It seldom causes low biliary obstruction. It is a useful clue to the diagnosis of ACC by understanding the above mentioned imaging features combined with elevated serum a-fetoprotein.