良、恶性胰腺实性假乳头状瘤的CT和MRI诊断要点分析

Analysis of the CT and MRI findings for benign and malignant solid pseudopapillary pancreatictumor

目的 分析并归纳良、恶性胰腺实性假乳头状瘤（SPT）的CT和MRI特征性诊断要点，以期提高其诊断准确率。方法 回顾性分析经手术病理证实的38例胰腺良性SPT和10例实性假乳头状癌（SPC），分析其CT和MRI征象并归纳特征性诊断要点。结果 38例良性SPT均存在完整包膜，表现为T1、T2低信号，增强后呈延迟强化；10例SPC中9例包膜局部显示不清、不完整。18例良性SPT和6例SPC钙化均呈点状、结节状或弧线状。11例良性SPT和6例SPC瘤内出血，CT平扫呈稍高密度，T1呈稍高信号，T2呈稍低信号。7例良性SPT和5例SPC胰管扩张，胰管呈管状或串珠样扩张。38例良性SPT均未见周围血管受侵犯；4例SPC侵犯周围血管，血管壁表现为模糊。38例良性SPT均未见周围组织受侵犯；5例SPC侵犯周围组织，表现为瘤-组织边缘模糊，局部包膜不完整。结论 包膜、钙化、瘤内出血、胰管扩张、侵犯血管及周围组织为胰腺良性SPT和SPC具有特征性的CT和MRI征象，其中，包膜、是否侵犯血管及周围组织可作为两者的鉴别诊断要点。

Objective To analyze and summarize the characteristic diagnostic points of CT and MRI images for benign and malignant solid pseudopapillary pancreatic tumors. Results may have applications in improving the accuracy of these imaging modalities. Methods A total of 38 cases of solid pseudopapillary tumors（SPT） and 10 cases of solid pseudopapillary carcinomas（SPC） confirmed through surgery and pathology were retrospectively analyzed. The characteristic and diagnostic points of CT and MRI images were analyzed and summarized. Results Thirty-eight cases of SPT had complete capsules, which were characterized low signal on T1 and T2, and delayed enhancement after contrast injection. Nine cases of SPC had incomplete capsules. Eighteen cases of SPT and 6 cases of SPC showed punctate, nodular, or arcing calcification. A total of 11 cases of SPT hemorrhage and 6 cases of SPC hemorrhage were observed. CT scanning showed elevated T1 density and signals and attenuated T2 signals. Moreover, 7 cases of SPT and 5 cases of SPC showing duct, tubular, or beaded dilation; 4 cases of SPC with peripheral vessel invasion and unclear vascular walls; and 5 cases of SPC with surrounding tissue invasion were observed. Conclusions Capsulation, calcification, intratumoral hemorrhage, pancreatic duct dilation, and vascular and surrounding tissue invasion are the characteristic diagnostic points of SPT and SPC on CT and MRI images. Capsulation, blood vessel characteristics, and surrounding tissue invasion may serve as key points for the differential diagnoses of benign and malignant SPT.