Fluid-fluid levels in bone and soft tissue tumors demonstrated by MR imaging]

Fluid-fluid levels in bone tumors have been described in aneurysmal bone cysts and other cystic tumors of bones and soft tissue tumors. We experienced three bone tumors (simple bone cyst, bone metastasis, and osteosarcoma) and three soft tissue tumors (fibrosarcoma, two cases of cavernous hemangioma) that showed fluid-fluid levels on MR, and investigated their cause. Causes included blood in the cystic spaces, hemorrhage in the tumor, the telangiectatic component of the osteosarcoma, and the cavernous component of the hemangioma. No specific diagnosis could be made based on the finding of fluid-fluid levels. We conclude that fluid-fluid levels on MR are rather nonspecific findings in bone and soft tissue tumors and that the diagnosis should be made on the basis of other radiological and clinical findings.     

Soft tissue aneurysmal bone cyst

A soft tissue aneurysmal bone cyst located in the right gluteus medius of a 21-year-old man is reported. On conventional radiography, the lesion demonstrated a spherically trabeculated mass with a calcific rim. On CT scan, it showed a well-organized peripheral calcification resembling a myositis ossificans. On MRI, it presented as a multilocular, cystic lesion with fluid-fluid levels. The lesion had no solid components except for intralesional septa. Although findings on imaging and histology were identical to those described in classical aneurysmal bone cyst, diagnosis was delayed because of lack of knowledge of this entity and its resemblance to the more familiar post-traumatic heterotopic ossification (myositis ossificans).     

Giant cell tumor with secondary aneurysmal bone cyst: A unique presentation with an ossified extraosseous soft tissue mass

The authors describe a case of giant cell tumor (GCT) with secondary aneurysmal bone cyst (ABC) in a 44-year-old man with chronic, intermittent knee pain. A unique feature is the presentation of GCT with an ossified extraosseous soft tissue mass. Radiograph demonstrates a multiloculated lytic lesion in the distal meta-epiphyseal region of the femur with an adjacent extraosseous soft tissue mass. The soft tissue mass was partially ossified along its margin and internal septa. MRI demonstrates a multiloculated lesion in the distal femur with multiple fluid–fluid levels and cortical penetration of the lesion. Both the intraosseous lesion and extraosseous soft tissue mass have similar MR signal characteristics. At surgery, the intraosseous component was found to be contiguous with the extraosseous soft tissue mass through a cortical perforation. To the best of our knowledge, this is the first case report of GCT with aneurysmal bone cyst initially presenting with an extraosseous soft tissue mass.     

动脉瘤样骨囊肿的影像学诊断

目的：探讨动脉瘤样骨囊肿（ABC）的影像学特点。资料与方法：回顾性分析23例经手术病理证实的ABC的影像学表现，23例均摄X线平片和CT平扫。4例行MRI检查。结果：23例ABC发生于长骨18例，骨盆5例。ABC平片表现常为偏心性膨胀性骨破坏；CT平扫可见膨胀的骨壳内缘呈清晰弧形压迹，其中骨壳完整12例，断缺11例。病灶密度不均，19例可见蜂房样低密度影或液－液平面，15例出现软组织肿块；4例MRI主要表现为T1WI呈等低信号，T2WI呈大小不一高信号囊腔或液－液平面，3例增强扫描，2例无明显强化，1例轻度强化，囊间隔在T1WI、T2WI及增强后均为低信号。结论：X线平片简便经济，但对内部结构的显示有一定限度，CT和MR对内部结构及软组织的显示明显优于前者，对ABC具有很高的诊断价值。     

Fluid-fluid level: a nonspecific finding in tumors of bone and soft tissue

Fluid-fluid levels have commonly been reported to occur in aneurysmal bone cysts but have also been seen in telangiectatic osteosarcoma, chondroblastoma, and giant cell tumor of bone. The authors reviewed their experience with nine bone and three soft-tissue tumors that showed fluid-fluid levels on computed tomographic or magnetic resonance images. The bone tumors included fibrous dysplasia, simple bone cyst, recurrent malignant fibrous histiocytoma of bone, two classical osteosarcomas, and four aneurysmal bone cysts. The soft-tissue tumors included soft-tissue hemangioma and two synovial sarcomas. Except for aneurysmal bone cysts, these types of tumors have not been reported to be associated with fluid-fluid levels. Radiologic-pathologic correlation was available in seven patients; in all seven, the fluid-fluid levels indicated prior hemorrhage. The authors conclude that the presence of fluid-fluid levels in bone or soft-tissue tumors cannot be considered diagnostic of any particular tumor.     

Aneurysmal bone cysts of the jaws: CT and MR findings.

Two cases of aneurysmal bone cyst of the jaws, one in the mandible and the other in the maxilla, are reported in young girls 7 and 15 years old. One was a primary lesion; the other was associated with fibrous dysplasia. In both cases CT and MR demonstrated characteristic fluid-fluid levels. The diagnosis was confirmed after biopsy and surgical resection of the lesions.     

Giant aneurysmal bone cyst of the scapula: A case report

Aneurysmal bone cyst (ABC) is a benign bone tumor affecting mainly children and young adults. It occurs in the metaphysis of the long bones. The scapula is a very rare location. Imaging may be highly suggestive of ABC in cases of an osteolytic, expansive, and hemorrhagic lesion with fluid-fluid levels and thin septa. The diagnosis must systematically be confirmed by performing a biopsy, in order to adopt the best therapeutic strategy. There are several therapeutic means, but wide resection remains the gold standard. The evolution is very variable and can go from spontaneous healing to recurrence with the destruction of the bone. We report a rare case of aneurysmal bone cyst of the scapula in a young patient.     

Aneurysmal bone cysts: MR imaging at 1.5 T

Two patients with aneurysmal bone cysts of the pelvis were imaged using a 1.5-T magnetic resonance imaging device. Findings included multiple internal septations, cysts with fluid-fluid levels of varying intensity, and an intact rim of low-intensity signal completely surrounding the lesion. These findings allow a specific diagnosis of aneurysmal bone cyst to be made.     

Imaging characteristics of angiomatoid fibrous histiocytoma of bone

We present the first report of a patient with angiomatoid fibrous histiocytoma of bone in the radiology literature. This tumor initially eluded diagnosis due to its similarities with chronic hematoma and aneurysmal bone cyst. Only two cases of angiomatoid fibrous histiocytoma have been reported in the radiology literature and both of these lesions were in the soft tissues. The fairly distinctive findings in our patient of multiple large cystic chambers with fluid-fluid levels are similar to the findings in the two soft tissue case reports, suggesting that imaging may be used to suggest this specific diagnosis regardless of location, especially in the clinical setting of unexplained hematoma or anemia. Mention of this diagnosis in the radiology report may aid in the final diagnosis at pathology, because special techniques, including fluorescent in situ hybridization, must be applied in order to fully evaluate for the diagnosis.     

Aneurysmal bone cyst of the coronoid process of the mandible.

A rare case of an aneurysmal bone cyst (ABC) involving the right coronoid process of the mandible in a 12-year-old girl is presented. The characteristic features with fluid-fluid levels within the lesion observed on Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) was helpful in the preoperative diagnosis.     

Telangiectatic osteosarcoma of the skull base.

We present a patient with a distinctive lesion of the skull base, which, at imaging, showed expansile destruction of the sphenoid bone, hemorrhage with fluid-fluid levels, and contrast enhancement of a solid portion. These features ordinarily suggest either giant cell tumor or aneurysmal bone cyst; however, pathologic examination confirmed instead a rare variant of osteosarcoma of the telangiectatic type. Although imaging findings can indicate any of these possibilities, biopsy is an essential step in arriving at the diagnosis.     

Pseudoanaplastic tumors of bone

Objective To discuss the concept of pseudoanaplastic tumors of bone, which pathologically show hyperchromatism and marked pleomorphism with quite enlarged, pleomorphic nuclei, but with no to extremely rare, typical mitoses, and to propose guidelines for their diagnosis.Design and patients From a database of 4,262 bone tumors covering from 1971 to 2001, 15 cases of pseudoanaplastic bone tumors (0.35% of total) were retrieved for clinical, radiographic and pathologic review. Postoperative follow-up after surgical treatment was at least 3 years and a maximum of 7 years.Results There were eight male and seven female patients. Their ages ranged from 10 to 64 years with average of 29.7 years. Pathologic diagnoses of pseudoanaplastic variants of benign bone tumors included: osteoblastoma (4 cases), giant cell tumor (4 cases), chondromyxoid fibroma (3 cases), fibrous dysplasia (2 cases), fibrous cortical defect (1 case) and aneurysmal bone cyst (1 case). Radiography of all cases showed features of a benign bone lesion. Six cases, one case each of osteoblastoma, fibrous dysplasia, aneurysmal bone cyst, chondromyxoid fibroma, giant cell tumor and osteoblastoma, were initially misdiagnosed as osteosarcoma. The remaining cases were referred for a second opinion to rule out sarcoma.Conclusions Despite the presence of significant cytologic aberrations, none of our cases showed malignant behavior following simple curettage or removal of bony lesions. Our observation justifies the concept of pseudoanaplasia in some benign bone tumors as in benign soft tissue tumors, especially in their late evolutionary stage when bizarre cytologic alterations strongly mimic a sarcoma.     

髂骨原发囊样骨肿瘤及瘤样病变的影像学诊断

目的:分析髂骨囊样骨肿瘤及肿瘤样病变的影像学表现。方法:回顾性分析经穿刺或/和手术病理证实的46例髂骨囊样骨肿瘤及肿瘤样病变影像学表现。46例全部行X线片检查,38例行CT检查,20例行MRI检查(增强16例)。结果:46例中骨肿瘤29例,其中良性肿瘤12例(骨巨细胞瘤4例,内生软骨瘤、软骨母细胞瘤各2例,血管瘤、骨母细胞瘤、骨样骨瘤、软骨黏液样纤维瘤各1例),恶性肿瘤17例(恶性巨细胞瘤、骨恶性纤维组织细胞瘤各1例,软骨肉瘤、淋巴瘤各4例,骨肉瘤7例),肿瘤样病变17例(单纯性骨囊肿1例,邻关节骨囊肿、动脉瘤样骨囊肿、嗜酸性肉芽肿各2例,骨纤维异常增生症10例)。发病部位为髂翼39例,髋臼7例。病变主要表现为髂骨囊样骨质破坏,呈膨胀性改变30例,硬化环形成24例,病变内见钙化灶14例,软组织肿块20例。结论:常见的髂骨囊样骨肿瘤和肿瘤样病变一般都具有某些特征性的CT表现,必要时综合X线、MRI表现,可提高定性诊断符合率。     

动脉瘤样骨囊肿的CT及MRI诊断(附21例报告)

目的分析动脉瘤样骨囊肿的CT及MR I表现,评价其影像学诊断价值。方法回顾分析21例经手术或穿刺证实的动脉瘤样骨囊肿的CT及MR I表现。结果病变在CT上有16例可见明显液-液平面,其上缘CT值低于下部,其中继发性动脉瘤样骨囊肿可见明显软组织肿块,而MR I图像上除1例继发性动脉瘤样骨囊肿未见明显液-液平面以外,其它20例均有明显液-液平面。且继发性动脉瘤样骨囊肿的软组织肿块显示得更加清楚。结论动脉瘤样骨囊肿大部分病例在CT和MR I上出现有液-液平面,具有一定特征性,但不是惟一性。     

骶骨肿瘤CT与MRI诊断

目的　了解骶骨肿瘤的CT和MRI表现特征。方法　分析 69例骶骨肿瘤的CT和MRI表现 ,包括动脉瘤样骨囊肿(ABC)、骨母细胞瘤、骨肉瘤各 1例 ,骨髓瘤 2例 ,淋巴瘤 3例 ,骨巨细胞瘤 5例 ,脊索瘤 2 3例 ,转移瘤 33例。结果　骨巨细胞瘤位于椎体和前部附件 ,呈溶骨性破坏 ;ABC位于后部附件 ,MRI有液 -液平面 ;骨母细胞瘤和骨肉瘤CT呈骨性密度 ,MRI信号较低 ,后者伴软组织肿块 ;2 2例脊索瘤伴骶前包块 ,1 1 / 1 6例CT上出现钙化 ,9例在T2 WI有条状低信号纤维结构和高信号粘液基质。骨髓瘤 (1例 )、淋巴瘤和转移瘤在T1 WI和T2 WI分别呈略低信号和较高信号 ,1例骨髓瘤在T2 WI呈较高信号。结论　CT和MRI可清楚地显示肿瘤的部位和范围 ,两者结合 ,多数肿瘤可以定性     

脊柱动脉瘤样骨囊肿的CT、MRI诊断

目的：分析脊柱动脉瘤样骨囊肿的CT、MRI表现,提高对该病的CT、MRI诊断和鉴别诊断。方法：回顾性分析经临床病理证实的12例脊柱动脉瘤样骨囊肿的CT、MRI表现。结果：12例脊柱动脉瘤样骨囊肿患者中颈椎3例,胸椎6例,腰椎3例;单独椎体侵犯1例,单发于椎板2例,同时累及椎体及附件者9例。CT表现局限性囊状或膨胀性骨质破坏,边界清晰,内可见分房骨嵴影,4例可见内部多发液一液平面影。MRI示膨胀性溶骨性破坏灶周围可见低信号影包绕,病灶内呈多发分房状改变,T1WI呈不均匀低／等信号;T2WI呈数个大小不等的高／等信号囊腔,10例可见不同信号强度的液一液平面影。增强扫描可见囊腔周缘明显强化,腔内出血和液体无强化。结论：脊柱动脉瘤样骨囊肿CT、MRI表现具有一定的特征性,能够做出正确诊断。     

Aneurysmal bone cyst: value of MR imaging and conventional radiography

Our objective was to investigate the accuracy and the diagnostic value of different imaging features of primary aneurysmal bone cysts (ABC) in conventional radiographs and MRI. Conventional radiographs and MR images of 34 patients with a suspected aneurysmal bone cyst were reevaluated by six independent radiologists in a blinded fashion. Morphological features, MR signal characteristics, and contrast enhancement patterns were assessed. Diagnoses were correlated with histology. Sensitivity and specificity of the different imaging findings for each imaging technique were calculated. In 24 patients ABC was histologically proven. In 10 cases diagnoses other than ABC were established. Conventional radiography and MRI each demonstrated a sensitivity of 76.4 and 77.8% with a specificity of 55.0 and 66.7%, respectively. With combined use of both imaging modalities sensitivity and specificity increased to 82.6 and 70%, respectively. The ABC was significantly more often seen as circumscribed lesion with bone expansion, lobulation, septa, and pathological cortical bone reaction than those cases with different diagnoses. Septal contrast enhancement proved to be a useful MR imaging finding in suspected ABC. The combined use of conventional radiographs and MRI revealed the highest sensitivity in the diagnosis of ABC in relation to histology. Magnetic resonance imaging provides improved diagnostic specificity and valuable information on soft tissue changes. Electronic Publication     

Fluid-fluid levels in giant cell tumors of bone: report of two cases

Fluid-fluid levels have been described in association with aneurysmal bone cysts, telangiectatic osteosarcoma, and a chondroblastoma. We report two cases of giant cell tumors of bone with fluid-fluid levels identified by computed tomography and, in one case, by magnetic resonance imaging. This finding has not previously been associated with giant cell tumors. The radiographic features of the fluid-fluid levels cannot be distinguished from those reported in other osseous neoplasms.     

原发性与继发性动脉瘤样骨囊肿CT表现

目的评价CT对诊断与鉴别原发性与继发性动脉瘤样骨囊肿的价值。方法回顾性分析9例经手术病理证实原发性与继发性动脉瘤样骨囊肿的CT征象,并进行献复习。结果9例患中骨皮质缺损征象出现率(67％)高于“液一液平面”出现率(44％)。继发性动脉瘤样骨囊肿骨嵴明显粗大,可构成分房。9例病灶内呈不均匀软组织密度,增强后强化明显。结论CT检查有助于动脉瘤样骨囊肿早期定性诊断,并有助于鉴别原发性与继发性病灶。     

Non-epiphyseal chondroblastoma arising in the iliac bone, and complicated by an aneurysmal bone cyst: a case report and review of the literature

Chondroblastoma is a benign bone tumor that typically arises in the epiphysis of a long bone. However, when it occurs in non-epiphyseal location in flat bones, it may create a diagnostic problem. We describe such a case of chondroblastoma arising in the iliac bone. A 29-year-old man was incidentally found to have a bony pelvic lesion while undergoing evaluation for Crohn’s disease. The radiographs and CT revealed an expansile lytic lesion in the right iliac bone. A core biopsy of the lesion was performed. The histopathology revealed the lesion to be a chondroblastoma with secondary features of aneurysmal bone cyst. An en bloc surgical resection of the tumor was performed.