胸膜外孤立性纤维瘤的 CT、MRI 表现及其病理基础

Extra-Pleural Solitary Fibrous Tumor:CT and MRI Findings with Corresponding Pathological Basis

目的分析胸膜外孤立性纤维瘤(ESFT)的CT、MRI表现及其病理基础,提高对本病的认识和诊断水平。方法回顾性分析12例经手术病理证实的ESFT的CT、MRI和病理学表现。结果 12例ESFT中,发生于颅内、盆腔各5例,腹膜后2例。良性8例,交界性2例,恶性2例。8例行CT扫描,其中6例良性ESFT为边界清楚的类圆形肿块,2例恶性ESFT边界不清,与周围组织粘连或侵犯周围组织。8例肿块CT密度均不均匀,伴有斑片状低密度区,CT增强扫描动、静脉期肿块不均匀强化,延迟期肿块持续强化且强化范围扩大,呈"快进慢出"型均匀一致强化。4例行MRI,T1WI:3例病灶为等信号,1例为多发分隔囊状低信号;T2WI:3例病灶表现为等、低混杂信号,病灶内见少量斑片状高信号影,1例为多发分隔囊状高信号。MRI增强扫描病灶实质部分均明显强化,T2WI低信号区显著强化,坏死囊变区未见强化。免疫组织化学:波形蛋白(Vimentin)阳性率100.0%(7/7),CD34阳性率100.0%(8/8),Bcl-2阳性率80.0%(4/5),CD99阳性率71.4%(5/7);S-100阴性率100.0%(6/6),平滑肌肌动蛋白(SMA)阴性率100.0%(5/5),细胞角蛋白(CK)阴性率83.3%(5/6)。结论胸膜外孤立性纤维瘤CT、MRI表现有一定的特点,CT平扫密度不均匀,增强动、静脉期不均匀强化,延迟期持续均匀一致强化;MR T2WI上呈低信号、增强扫描呈显著强化。

Objective To analyze the CT and MRI findings of extra pleural solitary fibrous tumor （ESFF） and to im- prove the understanding and diagnostic ability prior to surgery. Methods CT, MRI and pathological findings were retro- spectively reviewed in 12 patients with ESFT proved by operation and pathology. Results The tumors were found in head in 5 cases, pelvic region in 5 cases, and retroperitoneal region in 2 cases. Eight cases were found on CT scan, among which there were 6 benign lesions, presented with well defined round or elliptic margins; 2 malignant lesions with unclear and invasive margins. All of the eight tumors showed heterogeneous masses with patchy, necrotic foci. Contrast enhanced CT images showed marked, heterogeneous enhancement and progressive enhancement in all lesions. On unenhanced MRI, the lesions presented isointensity on T1WI, hyper or isointensity on T2WI in 3 lesions, multiple cystic hypointense and hy- perintense signal in one lesion. On contrast enhanced MRI, solid parts of the mass showed intensive enhancement. Immuno- histochemical staining showed that Vimentin positive was 100. 0%, CD34 （100. 0% ）, Bcl 2 （80. 0%）, CD99 （71.4%）, as well as negative S 100 （100.0%）, SMA （100.0%）, and CK （83.3%）. Conclusion CTand MRI findings of ESFT have certain characteristic findings, especially heterogeneous masses with progressive enhancement on CT scan, hypointense signal on T2WI and strongly enhancement on contrast enhancement MRI scan.