肝脏血管平滑肌脂肪瘤

1、肝脏血管平滑肌脂肪瘤的影像学及病理学分析付10例报道并文献复习张鑫 严森祥 肖文波 许顺良作者单位：310003，杭州，浙江大学医学院第一附属医院放射科摘要 目的 分析肝脏血管平滑肌脂肪瘤的CT及MR的影像学特点与病理基础，减少对该肿瘤的误诊。 材料与方法 回顾性分析10例11个病灶肝血管平滑肌脂肪瘤的CT及MR的影像学表现，按不同病理组织学亚型进行对照分析。结果 10例肝脏血管平滑肌脂肪瘤中，脂瘤型3例，血管瘤型1例，肌瘤型1例，混合型5例。脂瘤型以脂肪成分为主，CT、MR均可显示脂肪密度或信号。血管瘤型以血管成分为主，CT、MR增强可见动脉期明显强化，门静脉期密度或信号仍高于同期肝实质。肌

2、瘤型主要是由平滑肌成分为主，脂肪成分很少，混合型三种成分含量相似，CT平扫为较均匀低密度，MR平扫T1W呈低信号，T2W呈稍高信号，增强扫描CT、MR均呈动脉期明显强化，门静脉期仍有强化。结论 不同病理组织学类型的肝脏血管平滑肌脂肪瘤，CT和MR表现有所不同，这取决于肿瘤所含的主要组织学成分。了解肿瘤不同的组织学亚型与影像学表现之间的关系，有助于提高肝脏血管平滑肌脂肪瘤术前诊断准确率。关键词 肝脏 血管平滑肌脂肪瘤 体层摄影术，X线计算机 磁共振成像 Correlation between pathology and image characteristics of hepatic angio

3、myolipoma Zhang xin,Yan senxiang,Xiao wenbo,Xu shunliang. Department of Radiology, First Hospital, Medical College of Zhejiang University, Hangzhou, 31003, ChinaAbstract Objective To discuss the imaging including CT and MRI characteristics of hepatic angiomyolipoma based on pathological findings, wi

4、th the aim of more accurate diagnosis of the rare lesion of the liver. Material and Method Ten patients with 11 angiomyolipomas were retrospectively analyzed, and their CT and MRI appearances were correlated with the pathohistological subtypes of the disease. Results Ten patients with hepatic angiom

5、yolipomas were subcategorized into lipomatous （3 cases）, angiomatous(1), myomatous(1) and mixed(5) types, where lesions of the lipomatous type were mainly composed of adipocytes which could be easily recognized on both CT and MRI. Abnormal vessels were commonly seen in the angiomatous lesions, which

6、 showed pronounced enhancement in the early arterial phase and remained higher than or isodense with the normal parenchyma in the portal phase. The myomatous type was predominantly composed of leiomyoid cells mixed with small amount of adipocytes. The mixed type was the most often, evenly comprising

7、 sheets of epithelioid muscle cells admixed with islands of adipocytes and abnormal vessels, and showing homogeneously low density on plain CT and low signal intensity on T1-weighted, intermediately high signal intensity on T2-weighted MRI scans. On dynamic study with both CT and MRI, the mixed type

8、 exhibited obvious enhancement, which retained to some degree during the portal phase. Conclusion In hepatic angiomyolipomas, there showed discrete CT and MRI appearances with different pathological subtypes depending on the components of the tumor. More accurate diagnosis can be achieved with the k

9、nowledge of correlation between pathological subtype and imaging characteristics. Keywords liver angimyolipoma tomography，X-ray computed MRI肝脏血管平滑肌脂肪瘤（Hepatic Angiomyolipoma HAML）是肝脏少见的良性肿瘤，它由不同含量的脂肪细胞、平滑肌细胞和畸形血管组成。HAML术前诊断困难，易误诊为肝癌、肝脏血管瘤等。笔者将10例经过病理证实的HAML病例进行回顾性分析，旨在提高对本病的认识。材料和方法我院1999年2月2005年1月经

10、手术病理证实的HAML共10例11个病灶。其中男性3例，女性7例，男女比例3：7，年龄2664岁，平均年龄39.9岁。临床症状表现为上腹部不适伴隐痛4例，无明显临床症状6例。10例患者均无神经系统症状。10例中1例有甲状腺癌手术史，1例有肾脏血管平滑肌脂肪瘤手术史。实验室检查HBsAg（-）9例，HBsAg（）1例，10例肿瘤标记物AFP、CEA、CA 125 、CA 199 均在正常范围。10例患者均行CT平扫及增强扫描。CT扫描4例使用Toshiba 600 CT机、2例使用Maconi 8000 4排螺旋CT机，4例使用Toshiba Aquilion 16多排螺旋CT机，扫描矩阵为51

11、2×512，视野20cm×20cm，层厚110mm，层间距05mm。增强扫描使用60碘海醇。10例患者中5例行了MR平扫及增强，MR检查机型均为Signa Excite GE 1.5T超导型核磁共振机。扫描层厚810mm，间隔12mm。常规行横断面T1WI SE、T2WI FSE（抑脂）平扫及钆喷葡胺增强3期扫描。 结果按Tsui等1提出的根据肿瘤所含的主要组织学成分进行分型的方法对本组10例11个病灶肝脏血管平滑肌脂肪瘤进行病理分型，其中脂瘤型3例，血管瘤型1例，肌瘤型1例，混合型5例。肿瘤大小3.114.5cm，平均6.7cm。术后所有肿瘤大体病理所见肿瘤境界清楚，均未

12、发现明确包膜。在3例脂瘤型肝脏血管平滑肌脂肪瘤中，脂肪含量>60。CT密度和MR信号与皮下脂肪相似，其中可见条索状、斑片状软组织密度或信号，增强扫描脂肪部分未见强化，软组织密度或信号部分强化较明显。（图1）在1例血管瘤型肝脏血管平滑肌脂肪瘤中，病理上以畸形血管为主。CT平扫呈低密度，其内可见点条状钙化，增强扫描呈动脉明显较均匀强化，门静脉期密度仍高于同期正常肝实质。（图2）在1例肌瘤型和5例混合型肝脏血管平滑肌脂肪瘤中，其主要表现为软组织肿块影，混合型有1例肿瘤内可见到灶性脂肪密度或信号，4例虽然脂肪含量约30，但不呈灶性，为弥漫存在，在CT和MR上未能显示，增强扫描肿瘤呈明显强化，门静

13、脉期仍有强化， 1例肌瘤型、2例混合型呈稍低于同期肝实质密度或信号，2例混合型呈等于同期肝实质密度或信号，2例混合型呈稍高于同期肝实质密度或信号。所有10例肝脏血管平滑肌脂肪瘤中，有7例8个病灶增强扫描肿瘤内或边缘可见粗大血管显影（图4）。1例肾脏血管平滑肌脂肪瘤术后患者，在CT、MR检查发现同时在肝脏、肾脏、后腹膜及后纵隔患有血管平滑肌脂肪瘤。10例患者术前影像学诊断为HAML有6例，3例诊断为原发性肝癌，1例因为有2年前甲状腺癌手术史，且左右肝内各可见一肿瘤病灶而诊断为肝脏转移瘤。讨论血管平滑肌脂肪瘤（Angiomyolipoma AML）是一种良性间叶性肿瘤，多发生于肾脏，发生在肝脏及其

14、他脏器者罕见。自Ishak21976年首次报道发生于肝脏的血管平滑肌脂肪瘤，至今国内外仅有百多例报道，且多为个例报道，10例以上的报道较少见并以CT影像所见报道为主，而笔者搜集了10例11个病灶，并结合病理组织学特点作回顾性分析，希望在对该肿瘤的认识和术前诊断准确性上有所助益。HAML多见于青年女性，少数病例可与多发性结节硬化、肾脏血管平滑肌脂肪瘤并发。临床上，HAML常无自觉症状，部分表现为肝区隐痛或右上腹不适。病理上，HAML是由不同含量的脂肪细胞、平滑肌细胞和畸形血管组成。Tsui等根据HAML中的三种成分比例不同将其分为4个型：脂瘤型、血管瘤型、肌瘤型和混合型。不同病理学类型其影像学表

15、现亦有所不同。脂瘤型主要是由分化成熟的脂肪细胞组成，肿瘤周边或其间可见少量畸形厚壁血管和梭形平滑肌细胞。因而在CT平扫示肿瘤组织密度与脂肪相似，并可见条索状、斑片状软组织密度，MRI平扫在短T1长T2脂肪信号内出现条索状、斑片状稍长T1稍长T2信号。增强扫描脂肪成分无明显强化，条索状、斑片状软组织结构强化明显，这与肿瘤内粗大的畸形血管有关。肿瘤内存在较多脂肪是脂瘤型HAML的特征性表现之一3-5。本型需与脂肪瘤、高分化型脂肪肉瘤相鉴别。脂肪瘤常由单一脂肪组成，CT、MR呈均匀脂肪密度或信号，增强扫描无明显强化；肝脏脂肪肉瘤发病率较HAML更低，其内软组织成分增强扫描呈轻度强化6，可与动脉期明显

16、强化的HAML相鉴别。血管瘤型是由大量的畸形厚壁血管及平滑肌细胞组成，脂肪成分较少，影像学上往往见不到。CT平扫呈低密度，其内有时可见点条状血管样钙化，MR呈长T1稍长T2信号，钙化在MR T1W、T2W均呈低信号，增强扫描肿瘤动脉期明显均质强化，门静脉期仍呈高于同期肝实质的强化，但较动脉期有所减退，延迟期呈低密度或低信号。术后病理显示肿瘤内的点条状钙化来源于肿瘤内的厚壁血管。本型的增强特点需与血管瘤相鉴别，肝脏血管瘤常见且常多发，增强扫描动脉期即出现强化，但通常在肿瘤边缘出现环形或结节样强化，随时间延迟逐渐向肿瘤中心强化，呈“早出晚归”的强化特征。仅有较小的血管瘤增强扫描时呈动脉期均匀强化，

17、但延迟扫描仍有明显强化。且MR平扫T2W为极高信号，呈“灯泡征”，肿瘤内极少见HAML所显示的点条状血管样钙化。 肌瘤型主要由平滑肌成分组成，脂肪成分少于10，混合型病理上表现为实性成片的肌样细胞混以片状脂肪细胞，其间穿插着不规则的厚壁血管。这两型因平滑肌含量较多，常呈实质性软组织肿块。CT平扫呈稍低密度软组织肿块，其内密度常不均匀，MR平扫T1W呈稍低信号，T2W呈稍高信号，信号常较混杂，这与肿瘤内成分混杂有关。增强扫描肿瘤动脉期强化较明显，门静脉期仍有强化，呈稍高或等于同期肝实质密度、信号，延迟扫描肿瘤边缘可出现假包膜样环形强化。本型需与肝细胞性肝癌、肝腺瘤等相鉴别。肝细胞性肝癌动态增强扫

18、描呈也呈“快进快出”的特点，且延迟期扫描肿瘤边缘可见假包膜强化。病理学显示HAML没有假包膜形成，影像学所见假包膜样强化在术后与病理切片对照研究发现主要是由肿瘤周围的炎性细胞浸润和扩张的小胆管而形成。此现象文献报道很少7，且在T2W此假包膜样改变呈高信号，而肝细胞癌的假包膜在T2W呈低信号，此点可与肝细胞癌相鉴别。本组病例行MR检查较少，此现象还有待进一步验证。且肝细胞肝癌常有肝炎、肝硬化病史，血AFP检查常增高。肝腺瘤在肿瘤周边可见脂肪密度、信号环，增强扫描肿瘤动脉期明显强化，但中心瘢痕无强化，门静脉期及延迟期强化减退呈低密度、信号，中心疤痕强化明显，周边环无强化。有人报道典型HAML 的肿

19、瘤血管呈卷发状或旋涡状，但出现率低8。笔者复习文献并结合本组病例发现，无论是哪种病理类型HAML，因其内含有畸形厚壁血管，且常较粗大，所以MR平扫肿瘤内有时可见流空的血管影像，增强扫描常可见强化的粗大血管。本组3例增强扫描且行肝动脉血管重建可见肝动脉分支延伸至肿瘤内，这在其他肿瘤少见，是HAML的又一特征性影像表现 9-10。综上所述，不同病理类型的肝脏血管平滑肌脂肪瘤因其所含的组织学成分比例不同，可呈不同的影像学改变，了解它们之间的关系把握特征性的影像学表现，有助于我们术前做出准确诊断。参考文献1 Tusi WMS，Colombari R，Partmann BC，et al.Heptic a

20、ngiomyolipoma:A clinicopathologic study 30 cases and delineation of unusual morphologic variants.Am J Surg Pathol,1999,23:310.2 Ishak KG. Mesenchymal tumors of the liver. In Okuda K and Peters RL , eds. Hepatocellular carcinoma. New York: John Wiley & Sons, 1976:247-307.3 Takayama Y, Moriura S,

21、Nagata J,et al. Hepatic angiomyolipoma: radiologic and histopathologic correlation. Abdom Imaging. 2002 Mar-Apr;27(2):180-3.4 Balci NC, Akinci A, Akun E,et al. Hepatic angiomyolipoma: demonstration by out of phase MRI. Clin Imaging. 2002 Nov-Dec;26(6):418-20.5 Jiang TA, Zhao QY, Chen MY,et al. Diagn

22、ostic analysis of hepatic angiomyolipoma. Hepatobiliary Pancreat Dis Int. 2005 Feb;4(1):152-5.6 Galant J,Marti-Bonmati L,Saez F,et al.The valve of fat-suppressed T2 or STIR sequence in distinguishing lipoma from well-differentiated liposarcoma.Eur Radiol,2003,13:337-343.7 Block S, Theilmann L. Angio

23、myolipoma of the liver. Dtsch Med Wochenschr. 2000 Jun 9;125(23):743-5.8 Chang JC,Lee YW,Kim HJ:Is fat in the liver friend or foe?Abdom Imaging,1994,19:546.9 Yan F, Zeng M, Zhou K,et al. Hepatic angiomyolipoma: various appearances on two-phase contrast scanning of spiral CT. Eur J Radiol. 2002 Jan;4

24、1(1):12-8.10 Hogemann D, Flemming P, Kreipe H, Correlation of MRI and CT findings with histopathology in hepatic angiomyolipoma. Eur Radiol. 2001;11(8):1389-95.World J Gastroenterol. 2003 Aug;9(8):1856-8.Related Articles, Links   Diagnosis and treatment of hepatic angiomyolipoma in 26 cases.Ren

25、 N, Qin LX, Tang ZY, Wu ZQ, Fan J.Liver Cancer Institute, Fudan University, Shanghai 200032, China. ningrenAIM: To summarize the experience of the diagnosis and treatment of hepatic angiomyolipoma (HAML). METHODS: The clinical, imaging and pathological features, and treatment strategies of 26 patien

26、ts with HAML treated at the authors' institute between October 1998 and January 2003 were retrospectively analyzed. All the patients received liver resection and were followed up till the study. Immunohistochemical assays were performed with a panel of antibodies. RESULTS: There was an obvious f

27、emale predominance (21:5), and most of the patients (18/26) had no symptoms. Heterogeneous high echo was found in ultrasonography and punctiform or filiform vascular distribution pattern was found in color Doppler-sonography in most of the lesions (21/26). All of the 5 lesions further enhanced with

28、Levovist showed early and prolonged enhancement. At contrast-enhanced spiral CT, the soft-tissue components of 24 lesions were markedly enhanced in the arterial phase and 18 lesions remained enhanced in the portal venous phase. MRI was performed in 9 patients, and showed hypointensity or hyperintens

29、ity on T1-weighted images and heterogeneous hyperintensity on T2-weighted images. Histopathologically, all lesions were composed of adipose tissues, smooth muscle and blood vessels with different proportions. Most lesions showed positive immunohistochemical staining for HMB45 (26/26), A103 (24/26) a

30、nd SMA (24/26). All of the 26 patients showed a benign course with no sign of recurrence. CONCLUSION: Preoperative radiological diagnosis of HAML is possible. The demonstration of intratumoral fat and central vessels is helpful in the diagnosis. HMB45, A103 and SMA are promising markers for patholog

31、ic diagnosis of HAML, and surgical resection is effective for the treatment of HAML.Angiomyolipoma of the liver with least amount of fat component: imaging features of CT, MR, and angiography.Yoshimura H, Murakami T, Kim T, Nakamura H, Hirabuki N, Sakon M, Wakasa K, Inoue Y.Department of Diagnostic

32、Medicine, Course of Biosystem Medicine, Osaka University Graduate School of Medicine D1, 2-2, Yamadaoka, Suita City, Osaka 565-0871, Japan.We report two cases of angiomyolipoma of the liver, where small amounts of fat on computed tomography, magnetic resonance imaging, and angiography made distingui

33、shing this tumor from other hypervascular tumors difficult. Recognizing the imaging features of no capsule, hypervascularity of the tumor including the fat component, and early venous drainage may be helpful for correctly diagnosing angiomyolipoma of the liver.Eur Radiol. 2001;11(8):1389-95.Related

34、Articles, Links   Correlation of MRI and CT findings with histopathology in hepatic angiomyolipoma.Hogemann D, Flemming P, Kreipe H, Galanski M.Department of Radiology, Hannover Medical School, Germany. Hepatic angiomyolipomas are rare and often mimic other liver tu

35、mors. The aim of our study was to describe the CT and MRI findings and to correlate imaging features with histopathology. The CT and/or MR images were available for retrospective analysis in seven patients. Patients had non-enhanced as well as enhanced CT (n = 6) or MRI (n = 4) before and after admi

36、nistration of Gd-DTPA (n = 2) or MnDPDP, a liver specific contrast agent, (n = 3). In three patients CT and MRI did not detect fat, and in two patients the angiomyolipomas were also histopathologically devoid of fat. Vascularity ranged from hypervascular (n = 4) with arteriovenous shunts (n = 1) to

37、equal (n = 1) or less (n = 2) postcontrast enhancement compared with the normal liver parenchyma. No uptake of the liver specific contrast agent, MnDPDP, was observed (n = 3). Predominantly, CT and MRI did not include angiomyolipoma in the differential diagnosis, and the initial histopathological ev

38、aluation was inconclusive in more than half the cases. Hepatic angiomyolipomas frequently manifest as solitary well-circumscribed heterogeneous masses in patients with no underlying liver disease or elevation of serum tumor markers. If present, the demonstration of intratumoral fat is helpful in the

39、 diagnosis of angiomyolipoma. The final diagnosis can be obtained by immunohistochemistryAbdom Imaging. 1998 Sep-Oct;23(5):520-6.Related Articles, Links   Angiomyolipoma of the liver: significance of CT and MR dynamic study.Ahmadi T, Itai Y, Takahashi M, Onaya H, Kobayashi T, Tanaka YO, Matsuza

40、ki Y, Tanaka N, Okada Y.Department of Radiology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.Angiomyolipoma is a benign mesenchymal tumor that has been reported frequently in the kidney but rarely in the liver. In the present study, we present four cases of hepatic angiomyo

41、lipoma with different radiologic appearances, discuss differential diagnosis, and review previously reported cases. One of our cases was followed for 8 years. Computed tomography (plain, enhanced, and dynamic study), magnetic resonance imaging (T1-weighted spin echo, T2-weighted spin echo, and dynam

42、ic study), ultrasonography, and angiography were performed in all cases. Although different radiologic appearances were observed in the tumors, based on different proportions of fat, blood vessels, and muscle, three cases were diagnosed as angiomyolipoma. In one case, it was quite difficult to make

43、radiologic diagnosis; hepatocellular carcinoma with fatty metamorphosis in part was most likely suspected, but histopathological examination revealed angiomyolipoma with few fat elements. In the present study, early and prolonged enhancement of the lesion with the special pattern of time density/int

44、ensity curve was significant for angiomyolipoma, and we suggest that preoperative radiologic diagnosis of the lesion is possible in most of the cases. However, it can be quite difficult to distinguish angiomyolipoma from some hepatocellular carcinomas with fatty metamorphosis.Am J Surg Pathol. 1999

45、Jan;23(1):34-48.Related Articles, Links Hepatic angiomyolipoma: a clinicopathologic study of 30 cases and delineation of unusual morphologic variants.Tsui WM, Colombari R, Portmann BC, Bonetti F, Thung SN, Ferrell LD, Nakanuma Y, Snover DC, Bioulac-Sage P, Dhillon AP.Department of Pathology, Caritas

46、 Medical Centre, Kowloon, Hong Kong.Hepatic angiomyolipoma (AML) is frequently misdiagnosed. HMB-45 is a promising immunomarker for this tumor that leads to recognition of some AMLs with unusual morphology. The purpose of this collaborative study is to better define the morphologic variations of AML

47、. Thirty AMLs were examined, including four biopsy specimens and two fine-needle aspirates. The diagnosis was confirmed by the presence of HMB-45-positive myoid cells. Almost half the cases were originally misdiagnosed as carcinomas or sarcomas. There was marked female predominance (25:5), and the m

48、ean age was 48.7 years (range 29-68). Three patients (10%) had evidence of tuberous sclerosis and all had renal AML. According to the line of differentiation and predominance of tissue components, the tumors was subcategorized into mixed, lipomatous (> or = 70% fat), myomatous (< or = 10% fat), and angiomatous type. The mixed type was the most common (11 resected cases),