隆突性皮肤纤维肉瘤的影像表现及病理基础

The Imaging Manifestations and Pathological Basis of Dermatofibrosarcoma Protuberans

目的探讨隆突性皮肤纤维肉瘤(DFSP)的超声、CT和MRI表现及其病理基础。方法回顾性分析经手术病理证实的13例DFSP患者的影像学资料及病理结果,其中5例行超声检查,5例行CT扫描(增强3例),6例行MRI平扫+增强检查。结果 13例病灶均位于皮下浅表,超声表现为欠均匀低回声肿块,彩色多普勒示病灶内部血流信号丰富;CT平扫均呈等密度;T_1WI呈等信号或略低信号,T_2WI呈稍高信号。CT或MRI增强呈明显不均匀强化,内见条片状弱或不强化区;病理镜下见肿瘤细胞围绕血管呈席纹状密集排列,胶原纤维呈旋涡状排列,3例瘤体内见黏液样变区,2例伴纤维肉瘤样变区,免疫组织化学CD34均呈阳性。MRI上瘤体直径>5 cm的8例中,5例见"周围卫星灶"(4例术后复发)。结论 DFSP影像表现多呈均匀等密度/信号、明显不均匀强化,不强化区域与旋涡状排列的胶原纤维有关,密度不均匀的病理基础是黏液样变或肉瘤样变,当发现肿瘤体积增大、瘤周"周围卫星灶"时,术后易复发,适当扩大切除范围是必要的。

Objective To explore the imaging manifestations of Ultrasound,CT and MRI in dermatofibrosarcoma protuberans（ DFSP） and its pathologicalbasis. Methods Imaging data and pathological findings in 13 patients with pathologically-proved DFSP were retrospectively analyzed. Ultrasonography was performed in 5 patients,Plain CT was performed in 5cases and enhanced examination in 3 cases,Plain MR ＋ enhancement was performed in 6 cases. Results All of the 13 masses were located in subcutaneous region. Sonographic findings were inhomogeneous hypoechoic mass,Color doppler flow imaging showed rich blood flow signal in the internal lesions; The mass showed isodensity on plain CT; the mass was isointense or slightly hypointense on T_1 WI and slightly hyperintense on T_2WI; The post-enhanced lesions showed remarkably heterogeneous enhancement on both CT and MRI; Microscopically,the tumor cells were densely arranged in storiform patternaround the blood vessels,Collagen fibers were arranged spirally,3 cases of tumors had the areas of myxoid and 2 cases had the areas of fibrosarcoma degeneration,The immunohistochemical reports of all cases were positive for CD34. The diameters of tumors in 8 cases were more than 5 cm on MRI,among which 5 cases consisted of ＂ satellite lesions＂（ 4 cases were of postoperative recurrence）. Conclusion The imaging manifestations of Dermatofibrosarcoma Protuberans demonstrated more homogeneous isodensitysignal and obviously inhomogeneous enhancement,the region of no enhancement was related to the spirally arranged collagen fibers,the pathological basis of uneven density was myxoid or fibrosarcoma degeneration. It is seen that if the tumour is bigger in size and has satellite lesions,it has higher tendency to recur post operatively,therefore,it is necessary to properly consider the resection field during surgery.