下肢黏液性脂肪肉瘤的MRI表现(附1例报告及文献复习)

目的 探讨下肢黏液性脂肪肉瘤的MRI表现特点及鉴别诊断.方法 分析1例男性17岁患者经手术及病理证实的下肢黏液性脂肪肉瘤患者的MRI表现并就文献回顾.结果 肿瘤位于左大腿内侧深部肌肉间隙内,呈边界清楚的椭圆形,大小约12 cm×9 cm×4 cm.T1WI肿块与周围肌肉软组织相比呈不均匀性等信号,其间夹杂有云絮状略高及略低信号,包块周边可见细带状等信号包膜;T2WI呈较明显的高信号强度伴有少许等信号影, 细带状包膜呈较低信号强度;脂肪抑制扫描包块信号强度未见抑制.结论 下肢黏液性脂肪肉瘤较少见,MRI表现具有一定的影像学特点,有利于其术前诊断及鉴别诊断.     

下肢软组织黏液性-圆细胞型脂肪肉瘤的MR表现

目的探讨下肢软组织黏液性-圆细胞型脂肪肉瘤的MR表现及其与病理组织学的联系。方法回顾性分析6例手术病理证实为下肢软组织黏液性或黏液性-圆细胞型脂肪肉瘤患者的MR表现,观察肿瘤的位置、大小、形态、边界、内部结构及在T1W I、T2W I、T2脂肪抑制像(SPIR)和静脉注射Gd-DTPA后信号特点。结果肿块均位于下肢深部肌肉间隙内,形态多不规整,边界清楚,平均最大径约为15.2 cm,内部可见排列紊乱的纤维间隔,大部分纤维间隔厚度超过2 mm。T1W I肿块与周围骨骼肌相比呈均匀或不均匀等信号或略高、略低信号,T2W I呈高信号,脂肪抑制像肿块信号强度无减低,增强扫描见不同程度不均匀强化。结论MR可对下肢黏液性-圆细胞型脂肪肉瘤的诊断提供有价值的信息。     

四肢黏液样脂肪肉瘤CT、MR表现与病理相关分析

目的探讨四肢黏液样脂肪肉瘤CT、MR表现与其病理结构的关系,提高CT及MR诊断本病的准确率。方法对10例病理已证实的黏液样脂肪肉瘤患者的CT和(或)MR征象进行观察、分析并记录,与其组织标本病理改变进行对比分析。结果 10例均位于下肢,其中7例发生在大腿,3例发生在小腿。6例病变呈囊状液性密度(或信号),4例病变呈囊实性密度(或信号)。CT和(或)MR平扫呈囊状液性密度/信号的成分,在病理上对应为黏液样间质;病变实性部分在病理上对应的是肿瘤细胞密集区。行MR检查的8例病变中,4例可见"线"样、"花边"状或"云絮"状短T1WI信号,病理上对应为黏液基质内不同阶段的不成熟脂肪细胞。结论黏液样脂肪肉瘤CT、MR表现与其组织病理改变密切相关,熟悉其病理学表现对影像学做出正确诊断至关重要。     

原发性四肢软组织脂肪肉瘤MRI表现与病理学对照

目的：探讨四肢软组织脂肪肉瘤MRI表现与组织分化程度的关系,提高诊断准确性。方法：对经手术、病理证实的10例原发性四肢软组织脂肪肉瘤的MRI表现和特征与术后病理标本进行回顾性对照分析,了解肿瘤的大小、形态、边界、信号特点和邻近组织结构侵犯的情况,以找出它们间的关系。结果：10例中分化成熟型5例（脂肪肉瘤中脂肪瘤样脂肪肉瘤4例,硬化型1例）,黏液型2例,多形性2例,1例去分化型。分化成熟型含有大量成熟脂肪,在T1、T2WI像均高或较高信号,肿瘤边界清楚、信号较均匀。粘液型脂肪肉瘤含大量粘液基质,有少量分化良好、增生的脂肪母细胞,在MRI上无或少量的脂肪信号,信号轻度不均匀。多形性脂肪肉瘤属高度恶性肿瘤,信号明显不均匀,通常无明显脂肪信号显示,周围组织结构受浸润和水肿,去分化型瘤体体积大,信号明显不均匀,增强明显强化。结论：MRI表现和特征能反映软组织脂肪肉瘤的组织学特点,可清楚地显示肿瘤的大小、边界、累及范围及与周围组织的关系,可初步评估肿瘤的分化及恶性程度。     

MRI对软组织肿瘤的鉴别诊断价值

目的:探讨软组织肿瘤的MRI表现及其组间鉴别诊断。方法:回顾性分析本院经手术病理证实的50例软组织肿瘤的病例资料,其中外周神经鞘瘤13例,侵蚀性纤维瘤10例,纤维肉瘤14例,恶性纤维组织细胞瘤7例,腺泡状软组织肉瘤6例。所有患者均行MR平扫,18例行MR增强扫描,其中2例行MR血管成像,2例行MR波谱成像。结果:50例软组织肿瘤中45例发生于四肢。纤维肉瘤与侵蚀性纤维瘤长径最长,约112.73mm与112.98mm,外周神经鞘瘤长径最短,约37.75mm。50例肿瘤边界均较清楚,T1WI呈等信号或稍高信号,T2WI呈高信号夹杂多发线样或片状低信号分隔。外周神经鞘瘤为类圆形软组织肿块,MRI特异征象为"靶征"、"神经出入征"及"脂肪彗星尾征"。侵蚀性纤维瘤T2WI呈高信号且有多发粗条状低信号分隔。纤维肉瘤主要表现为多发囊变坏死、出血及邻近组织受侵犯。恶性纤维组织细胞瘤多呈边界不清的分叶状,可见囊变坏死与出血灶,T2WI背景呈高信号。腺泡状软组织肉瘤多呈类圆形,病灶内可见血液流空信号及线样低信号分隔。结论:好发于四肢的T1WI呈等信号或稍高信号的软组织肿瘤极易混淆,但各种肿瘤的MRI表现有差异,再结合各自的临床特征,鉴别五种肿瘤并不困难。     

四肢软组织脂肪肉瘤的MRI与病理对照研究

目的探讨四肢软组织不同病理类型脂肪肉瘤的MRI表现。资料与方法回顾性分析12例经病理证实的四肢脂肪肉瘤患者的MRI资料,并与病理结果对照。结果2例分化良好型由>75%的脂肪信号和非脂肪成分组成,后者表现为(2mm的间隔和结节,呈长T1、长T2信号。5例黏液型中2例主体呈等/长T1、长T2信号,内见间隔和斑片状脂肪信号区;3例呈以长T1、长T2信号为主的混杂信号,仅1例内见斑片状脂肪信号,部分伴有坏死、出血、轻度骨皮质破坏和腹股沟淋巴结转移。1例去分化型呈以稍长T1、长T2信号为主的混杂信号,内见结节状脂肪信号,伴邻近肌肉水肿和轻度骨皮质破坏。4例多形型呈以长T1、长T2信号为主的混杂信号,几乎无脂肪,部分伴坏死、出血、邻近肌肉水肿和骨质破坏。行增强扫描的2例黏液型呈明显不均匀强化。结论根据脂肪肉瘤的MRI表现可以推测肿瘤的组织学分化程度,为临床提供准确、可靠的信息。     

软组织病变磁共振短T2信号的病理基础

目的：分析软组织病变在T2WI出现低信号区的病理基础。材料和方法：对在TzWI出现低信号区的45个软组织肿块(良性27个，恶性18个)进行组织学检查，分析其与MR表现之间的关系。结果：神经鞘瘤、黏液性脂肪肉瘤、软骨肉瘤等为局限性低信号，色素性绒毛结节性滑膜炎(PVNS)呈弥漫性低信号。低信号区与病灶内胶原纤维增多，细胞成分较少，含铁血黄素沉着以及钙化、骨化等相对应。结论：胶原纤维、钙化和骨化等多种因素都可造成病灶在T2WI出现低信号区，分析低信号的病理基础有助于部分肿瘤的诊断。     

磁敏感加权成像对四肢软组织海绵状血管瘤临床应用初探

目的:探讨磁敏感加权成像在四肢软组织海绵状血管瘤的影像学表现特征及其应用价值。方法:分析11例经手术及病理证实的四肢软组织海绵状血管瘤常规MR表现及SWI表现。结果:MR表现分为:①局限肿块型7例,T1WI呈等或稍高信号,4例T2WI呈高信号;3例T2WI呈高、低混杂信号;②弥漫蔓藤型4例,T1WI呈等或稍高信号,T2WI及T2WI脂肪抑制呈高信号或高、低混杂信号。SWI表现:①肿瘤显示:4例局限肿块型呈较均匀稍高信号,3例局限肿块型及4例弥漫蔓藤型呈混杂信号或低信号为主,其间混杂条索状高信号;②静脉引流血管显示:4例局限肿块型为低回流型,3例局限肿块型及4例弥漫蔓藤型为高回流型;③肿瘤钙化与出血的鉴别:5例肿瘤钙化相位图以低信号为主,周边环以高信号;7例出血灶信号与之相反。结论:SWI序列可以客观的反映软组织海绵状血管瘤的构成成分,较常规序列可以提供更多的信息,为临床诊断及治疗方案的选择提供有重要的价值。     

软组织滑膜肉瘤的CT和MRI诊断

目的：探讨软组织滑膜肉瘤的影像学表现。方法：回顾性分析17例经手术病理证实的软组织滑膜肉瘤患者的临床及影像学资料,分析其影像学征象。结果：大部分滑膜肉瘤影像表现为邻近关节边界较为清楚的团块状或分叶状软组织肿块,肿瘤体积一般较大（〉5 cm,88%）。CT平扫可见肿瘤大部分密度与肌肉密度相似,其内可见范围不等的低密度区,1例见团块状钙化,2例见斑点状钙化,主要位于肿块的周边。较大的肿瘤（〉5 cm）在MR T1WI上与肌肉信号相比呈不均匀等信号或稍高信号,在T2WI上表现为以高信号或稍高信号为主的混杂信号,5例肿块内可见低信号分隔;较小的肿瘤（〈5 cm）在各序列上均表现出信号的均匀性;增强扫描大部分肿瘤呈明显不均匀强化。结论：软组织滑膜肉瘤的影像学表现具有一定的特征性,CT和MRI综合评价有助于提高滑膜肉瘤的诊断准确性。     

MRI对下肢软组织肿瘤及肿瘤样病变的诊断价值

目的:探讨MRI对下肢软组织肿瘤及肿瘤样病变的诊断价值。方法:回顾性分析25例经病理证实的下肢软组织肿瘤及肿瘤样病变的MRI表现。结果:25例中,良性11例,其中脂肪瘤5例,骨化性肌炎1例,假性动脉瘤1例,血管瘤4例;恶性14例,其中滑膜肉瘤6例,转移瘤3例,恶性纤维组织细胞瘤1例,平滑肌肉瘤1例,纤维肉瘤1例,脂肪肉瘤2例。良性组肿块最大径平均(8.36±3.50)cm,恶性组(11.9±4.61)cm,2组差异有统计学意义(P0.05)。良性组病变内部信号T1WI、T2WI以均匀中等或中等偏高信号为主,1例伴瘤周水肿;恶性组病变内部信号T1WI、T2WI以不均匀低信号为主的混杂信号,4例伴瘤周水肿(P0.05)。良性组6例未强化,恶性组均不同程度强化;良性组5例STIR呈低信号,恶性组2例STIR呈低信号;良性组无周围组织侵犯,恶性组8例伴周围组织侵犯,以上征象2组差异均有统计学意义(均P0.05)。结论:MRI能清晰显示软组织肿瘤及肿瘤样病变的边界、范围、大小、内部成分及与周围组织的关系,对良恶性的鉴别诊断价值较高。     

MR imaging of liposarcomas: correlation of MR features and histology

The magnetic resonance (MR) imaging features of liposarcoma were correlated with histology in 15 patients. The MR findings for liposarcoma were not specific. The six myxoid liposarcomas and two atypical lipomatous tumors, however, had distinctive MR features, i.e., nodular masses of slightly heterogeneous intermediate to high signal intensity (SI), intermingled with high SI septa on T1-weighted images. The T2-weighted images demonstrated the relative reversal of these regional SI characteristics. Additionally, MR correctly identified the presence of fat in all eight cases in which it was pathologically present. The fat in two atypical lipomatous tumors was inseparable on MR from the subcutaneous fat. Magnetic resonance appears useful for preoperative staging and follow-up studies of liposarcomas. It may be helpful in identifying patients with myxoid liposarcoma and atypical lipomatous tumors who have longer survival times.     

四肢黏液样脂肪肉瘤的MRI诊断

目的探讨四肢黏液样脂肪肉瘤的临床和MRI特点。方法对7例经病理证实的四肢黏液样脂肪肉瘤的临床和MRI资料进行了回顾性分析。患者年龄41-59岁，中位年龄51岁。结果3例肿瘤发生在大腿，2例在小腿，1例在足部，1例在肩部；6例位置深在，1例位置表浅。与肌肉相比病变在T1WI上主要呈等或稍低信号，6例可见“线”状、“花边”状或“云絮”状高信号；在T2WI上病变与脂肪相比大部分区域呈高信号；增强扫描病变均呈不均匀的显著强化；病变内部可见分隔，边缘清楚，周围无明显水肿，均未侵犯邻近骨骼。结论四肢黏液样脂肪肉瘤MRI表现有一定特点，在T1WI上主要呈等或稍低于肌肉的信号，并可见脂肪成分所致的“线”状、“花边”状或“云絮”状高信号，在T2WI上则以高于脂肪的信号为主，增强扫描呈不均匀的显著强化。     

Soft tissue liposarcoma: histological subtypes,MRI and CT findings

PURPOSE: Liposarcoma is the second most common malignancy of soft tissues. The commonly accepted classification of liposarcoma includes five basic histological categories: well-differentiated, myxoid, round cell, dedifferentiated and pleomorphic liposarcoma. The clinical behaviour of liposarcoma closely reflects its histological appearance, so that to identify the histological subtypes is very important for both prognosis and therapy. The aim of this study was to ascertain whether the histological features of liposarcoma subtypes can be correlated with MRI (Magnetic Resonance Imaging) and CT (Computed Tomography) findings by retrospectively evaluating nineteen cases of histologically-proved liposarcoma. MATERIALS AND METHODS: The MRI examinations performed over the past eight years on nineteen patients affected by liposarcoma were retrospectively reviewed. All patients underwent ultrasound and MRI examination; T2 and T1-weighted sequences were available in all cases and fat-saturated sequences in 4 cases; all patients were administered paramagnetic contrast material. CT scans were obtained in twelve patients. All patients had a biopsy, surgical resection and histology. RESULTS: The study group had 7 well-differentiated, 8 myxoid, 3 pleomorphic and 1 round cell liposarcoma. Well-differentiated liposarcomas had largely lipomatous appearance on both CT and MRI, typically with septa and areas showing high signal intensity on T2w MR images and low signal intensity on T1w images, and slightly hypodense compared to the muscle in CT, representing the sarcomatous areas. Myxoid liposarcomas were mildly heterogeneous with typical high signal intensity on T2w images and isointense to the muscle in T1w images, with lacy or linear septa of fatty tissue in six cases. The pleomorphic and round-cell subtypes demonstrated marked heterogeneity on MR images, with areas of necrosis and heterogeneous contrast enhancement, indistinguishable from other high-grade sarcomas. DISCUSSION AND CONCLUSIONS: Well-differentiated liposarcoma may be distinguished from other types of liposarcoma by its largely lipomatous appearance. Myxoid liposarcoma may be distinguished on the basis of its homogeneous or mildly heterogeneous structure due to the large amounts of the extracellular myxoid material that give it its typical MR appearance. Both well-differentiated and myxoid liposarcomas, the most common types accounting for about 50% of all liposarcomas, have a more favourable clinical behaviour than the other histological types. Differentiation of these from the other histological types of liposarcoma therefore has a high significance for prognosis and therapeutical approach. On the basis of our experience and of the literature, we believe that diagnostic imaging and in particular the MR examination may lead to a correct diagnosis.     

MRI of ganglioneuroma: histologic correlation study

PURPOSE: The purpose of this study was to evaluate the MR findings of ganglioneuroma and to correlate imaging and histologic features. METHOD: Conventional SE and contrast-enhanced dynamic MRI was used to examine 10 patients with pathologically confirmed ganglioneuroma. The morphologic features, signal intensity, and dynamic enhancement pattern of the tumors were retrospectively analyzed and correlated with histologic features. RESULTS: Capsules were present in all tumors histologically and were also detected in five tumors on postcontrast T1-weighted images. A whorled appearance corresponding to interlacing bundles of Schwann cells and collagen fibers on histologic specimens was visualized in five tumors on T1-and/or T2-weighted images. Tumors with markedly high signal intensity on T2-weighted images consisted histologically of a large amount of myxoid stroma and relatively few cellular and fibrous components. Tumors with intermediate to high signal intensity consisted of numerous cellular and fibrous components and little myxoid stroma. Early enhancement of tumors was usually lacking in dynamic MR studies; however enhancement gradually increased. CONCLUSION: The results suggest that the MR features of ganglioneuroma are well correlated with histologic findings.     

Infantile fibromatosis in childhood: findings on MR imaging and pathologic correlation

AIM: The objective of this study was to analyse the MR imaging findings of infantile fibromatosis of childhood and to correlate them with histopathological features. MATERIALS AND METHODS: Seven patients with histologically proven infantile fibromatosis were included in this study. The findings on MR images were retrospectively evaluated and then correlated with the pathological features. Findings on MR imaging evaluated included signal intensity, extent of hyperintense area on T2-weighted images, margins of the lesion, the degree and pattern of enhancement and the presence of fatty tissue. Pathological features evaluated included cellularity, collagenization, and myxoid change. A five point scale was used for the evaluation of the extent of hyperintense area on MR imaging, and each of pathological features. RESULTS: On T1-weighted images, the lesions were iso-intense in two patients; iso- and hypointense in three; and iso-, hypo- and hyperintense in two. On T2-weighted images, iso-, hypo- and hyperintense areas were mixed in all patients, the hyperintense area being the largest portion of the lesion. The margins of the lesions were infiltrative in four patients (57%), smooth in two (29%) and mixed in one (14%). Enhancement was marked in five patients (72%) and diffuse in five (71%). Regardless of the hyperintense signal intensity on T2-weighted images, the grades of each pathologic feature were variable. CONCLUSION: Infantile fibromatosis on MR imaging causes an enhancing mass, that is largely hyperintense on T2-weighted images. Areas of high signal intensity on T2-weighted images corresponded to variable grades of cellularity, collagenization, or myxoid change.     

Biliary atresia in neonates and infants: triangular area of high signal intensity in the porta hepatis at T2-weighted MR cholangiography with US and histopathologic correlation

PURPOSE: To correlate a triangular area of high signal intensity in the porta hepatis on T2-weighted magnetic resonance (MR) cholangiograms of biliary atresia with ultrasonographic (US) and histopathologic findings in a portal mass observed during a Kasai procedure. MATERIALS AND METHODS: Twenty-one consecutive neonates and infants (age range, 13-88 days; mean age, 59 days) with cholestasis underwent US and single-shot MR cholangiography. In 12 patients with biliary atresia diagnosed at histopathologic examination, MR cholangiographic findings in the porta hepatis were correlated with US and histopathologic findings in the portal mass. RESULTS: At US, eight of the 12 patients had round, linear, or tubular hypoechoic portions within a triangular cord; MR cholangiography revealed a triangular area of high signal intensity confined to the porta hepatis. Histopathologic examination of the portal mass revealed a cystic or cleftlike lesion surrounded by loose myxoid mesenchyme and platelike fetal bile ducts. Neither the large cystic lesion without ductal epithelium nor the small cleftlike lesion with scanty epithelium demonstrated bile staining. Similar areas of high signal intensity were not seen on T2-weighted images in the remaining patients (four with biliary atresia and nine with neonatal hepatitis). CONCLUSION: In biliary atresia, T2-weighted single-shot MR cholangiography can show a triangular area of high signal intensity in the porta hepatis that may represent cystic dilatation of the fetal bile duct.     

Liposarcoma of soft tissue: MRI findings with pathologic correlation

 Objective. To evaluate the MRI findings of liposarcomas of different histologic types and correlate these with the histopathologic features. Design. The MR images of seven liposarcomas were reviewed retrospectively to assess the tumor size, location, margination, signal characteristics and enhancement patterns in different histologic types. Patients. Seven liposarcomas comprising three well-differentiated, two myxoid and two pleomorphic types were evaluated. Results and conclusion. All tumors showed well-defined and mostly lobulated margins. The well-differentiated liposarcomas were composed mainly of fat with septations or nodules, were hyperintense on T2-weighted images, and demonstrated faint enhancement or no enhancement following intravenous contrast. Myxoid liposarcomas were homogeneous or mildly heterogeneous and a pseudocapsule was present in one case. Pleomorphic types showed a markedly heterogeneous internal structure. Both myxoid and pleomorphic lesions-showed moderate or marked heterogeneous enhancement after contrast administration. Well-differentiated liposarcomas may be differentiated from other types of the tumor by their largely lipomatous appearance. The malignancy grade increases in parallel with tumor heterogeneity and contrast enhancement.     

Inter- and intratumoral variability in magnetic resonance imaging of pleomorphic adenoma: an attempt to interpret the variable magnetic resonance findings

OBJECTIVES: The purpose of our study was to describe the various magnetic resonance (MR) findings of pleomorphic adenoma and to interpret these findings. METHODS: MR studies of 33 pleomorphic adenomas and 13 malignant tumors in the major salivary glands were reviewed. RESULTS: High signal intensity on short-inversion-time inversion recovery (STIR) and T2-weighted (T2W) images, progressive enhancement on dynamic MR images, and high apparent diffusion coefficient (ADC) values on diffusion-weighted (DW) images reflected myxoid-dominant components in pleomorphic adenomas. Hypercellularity with less-myxoid stroma showed reduced signal intensity on STIR and T2W images and also reduced ADC values on DW images, and the peak of time versus signal intensity curves (TICs) was reached earlier on dynamic MR images. CONCLUSIONS: The MR images of hypercellularity components in pleomorphic adenoma overlap with those of malignant parotid tumors. Detecting myxoid components by STIR, T2W, DW, and dynamic MR images is useful for predicting whether salivary gland tumors are pleomorphic adenoma or not.     

MRI of malignant fibrous histiocytoma of soft tissue: analysis of 13 cases with pathologic correlation

We reviewed the magnetic resonance (MR) appearances of 13 malignant fibrous histiocytomas (MFH) of soft tissue and correlated each with the respective lesion's histopathology. The MR images were evaluated for signal intensity on T1- and T2-weighted spin echo sequences, homogeneity of the lesion, presence of internal low signal septations, and margin definition. Histologic subtypes of MFH included storiform-pleomorphic, giant cell, myxoid, and inflammatory. We could not establish a correlation between MR appearance and histopathology. Instead, our series exhibited general features suggestive of malignant soft tissue neoplasms, namely poor margin definition, internal low signal septation, and heterogeneous high signal intensity on T2-weighted images.     

Myxoid solitary fibrous tumor of the retroperitoneum: MRI findings with the pathologic correlation.

We report here on a case of solitary fibrous tumor of the retroperitoneum, and the tumor displayed a predominantly myxoid histology. A 56-year-old man presented with an incidentally detected retroperitoneal mass. On the MR images, the mass was observed as having iso-signal intensity on the T1-weighted images and high signal intensity on the fat-saturated T2-weighted images. The mass showed intense enhancement on the Gd-DTPA enhanced T1-weighted images. At surgery, a well-defined solid mass was found in the left retroperitoneum. The histological diagnosis was made as solitary fibrous tumor with a predominantly myxoid histology.