Solid variant of aneurysmal bone cysts in long tubular bones: giant cell reparative granuloma

OBJECTIVE: The purpose of this study was to determine the age distribution, location, and imaging features of histologically proven solid variants of aneurysmal bone cysts in long tubular bones. MATERIALS AND METHODS: We performed a retrospective review of imaging studies of histologically proven solid aneurysmal bone cysts in long bones between 1961 and 2001. There were 30 cases comprising 29 radiographic, six CT, and eight MR imaging examinations. The lesions were evaluated for bone involved, location within a long bone, matrix, size, soft-tissue mass, and MR imaging characteristics. The imaging findings were correlated with the histologic findings. RESULTS: The patients were 17 females and 13 males ranging in age from 2 to 58 years (mean, 18 years). The bones involved were the femur (n = 10), the ulna (n = 7), the tibia (n = 7), the humerus (n = 2), the radius (n = 2), and the fibula (n = 2). The lesions were five juxtaarticular, 13 metaphyseal, one diametaphyseal, and 11 diaphyseal. The location was eccentric in 20 cases, of which two were intracortical and two periosteal, and central in 10. Lesion size varied between 1 and 7 cm. Thirty-three percent of lesions were nonaneurysmal. Four lesions were mineralized. A soft-tissue mass was present in four cases. Four lesions showed a permeative-lytic pattern simulating a malignant process. Unusual findings included periosteal reaction and development of a solid aneurysmal bone cyst in a preexisting fracture. MR imaging showed solid elements in all cases and pronounced edema in 50% of cases. CONCLUSION: Solid aneurysmal bone cyst is a reactive nonneoplastic bone lesion with varied imaging characteristics; one third of lesions are nonaneurysmal.     

Imaging study of ossifying fibroma with associated aneurysmal bone cyst in the paranasal sinus

Objective

To determine the CT and MR imaging features of ossifying fibroma with aneurysmal bone cyst of the paranasal sinus.

Materials and methods

We retrospectively reviewed 15 patients with histopathology-proven ossifying fibromas with aneurysmal bone cysts in the paranasal sinus. All 15 patients underwent CT and MR imaging. The following imaging features were reviewed: location, shape, margin, CT findings, and MR imaging appearances and time-intensity curve of dynamic contrast-enhanced MR imaging.

Results

Ossifying fibromas occurred in the maxillary sinus in one patient, sphenoid sinus in 2, frontal sinus in 3, frontoethmoid sinuses in 3, and ethmoid sinus in 6 patients. Ossifying fibromas showed an elliptic-shape and aneurysmal bone cysts revealed a multicystic appearance, with well-demarcated margins. On unenhanced CT, ossifying fibromas appeared isodense to gray matter with scattered calcifications in nine, ground-glass appearance in 6 patients and aneurysmal bone cysts showed mixed density. Ossifying fibromas appeared isointense to gray matter in 12 and slightly hypointense in three patients on T1-weighted images, and isointense in 4 and hypointense in eleven patients on T2-weighted images, with moderate or marked enhancement after administration of contrast material. The time-intensity curves of eight ossifying fibromas exhibited a rapidly enhancing and rapid washout pattern. The intracystic components of aneurysmal bone cysts showed heterogeneous signal intensity on MR images, with fluid–fluid levels identified clearly by T2-weighted images, without enhancement. The periphery and septa of aneurysmal bone cysts appeared isointense on MR images, with marked enhancement.

Conclusions

Fluid–fluid levels within an elliptic-shape mass with scattered calcifications or ground-glass appearance is highly suggestive of this complicated entity in the paranasal sinus.     

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.     

颅骨动脉瘤样骨囊肿的影像学表现

目的：探讨颅骨动脉瘤样骨囊肿的影像学表现，提高对颅骨动脉瘤样骨囊肿的认识。资料与方法：搜集经手术病理证实的4例颅骨动脉瘤样骨囊肿，全部病例均作了CT平扫与MRI检查，其中1例摄有颅骨平片，1例MR／增强扫描，1例DSA检查。结果：4例颅骨动脉瘤样骨囊肿中，1例位于左蝶骨嵴和左眶骨处，2例位于左颞骨。1例位于右额骨。CT上均表现为不同程度的膨胀性吹气球样溶骨破坏区，密度不均匀；MRI示有出血、囊变及液面，T1WI和R2WI上呈混杂信号，1例增强后示肿瘤实质和邻近脑膜强化；血管造影示血管有推移改变。结论：颅骨动脉瘤样骨囊肿的影像学表现有一定的特征性，CT与MRI相结合能提示诊断，并有助于评价周围结构。     

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     

Aneurysmal bone cyst of the temporal bone: MR findings.

MR findings in a case of aneurysmal bone cyst of the temporal bone are described. MR can suggest the diagnosis of aneurysmal bone cyst and also give ancillary information that is helpful for surgical treatment.     

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.     

MR扩散加权成像对颅内囊性肿块的鉴别诊断价值

目的 :探讨MR扩散加权成像对颅内囊性肿块的鉴别诊断价值。方法 :搜集有手术病理结果的患者 3 1例 ,其中表皮样囊肿 9例 ,蛛网膜囊肿 15例 ,囊性颅咽管瘤 4例 ,颅底囊性变神经鞘瘤 3例。所有病例均行MR常规T1WI、T2 WI及DWI扫描 ,回顾性分析各组病例的MR常规及扩散加权成像表现。结果 :在MR扩散加权图像上 ,所有 7例表皮样囊肿均为显著高信号 ,而在指数扩散加权像及ADC图上为等信号 ;其余病变在扩散加权图像上为低信号或伴等信号。结论 :MR扩散加权成像有助于表皮样囊肿与其它颅内脑外囊性肿块的鉴别 ,表皮样囊肿的扩散加权高信号主要是由“T2余辉效应”而非水分子扩散受限所致。     

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.     

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。     

Metachronous aneurysmal bone cysts with involvement of the humerus and the thoracic vertebrae

Metachronous aneurysmal bone cysts are rare. We report on a 32-year-old man who presented with an aneurysmal bone cyst of the thoracic spine 15 years subsequent to diagnosis of aneurysmal bone cyst of the humerus.     

Imaging features of subperiosteal aneurysmal bone cyst

PURPOSE: To analyze the imaging features of subperiosteal aneurysmal bone cyst. MATERIAL AND METHODS: The imaging material of 6 patients with biopsy-proved subperiosteal aneurysmal bone cyst was reviewed. Evaluation included patient demographics, lesion location and size, radiographic features, and intrinsic characteristics on CT and MR images. Review of histologic specimens was carried out by an experienced musculoskeletal pathologist. RESULTS: All lesions were located at the surface of long tubular bones (femur 3, tibia 2, humerus 1): 3 involved the diaphysis, 2 the dia/metaphysis, and 1 exclusively the metaphysis. Lesion size ranged from 2.5 to 6 cm in maximum diameter. Radiographs and CT images always showed a superficial bone defect, which on radiographs demonstrated irregular margins in 4 cases. All lesions caused an interrupted periosteal reaction (shell 3, trabeculated shell 1, Codman angle 2). MR images always showed a multicystic appearance with a hypointense rim, contrast-enhancing cyst walls, and fluid levels. Edema of adjacent soft tissues was present in all cases. CONCLUSION: Aneurysmal bone cyst in a subperiosteal location can demonstrate an aggressive radiographic appearance. MR imaging appears to be most valuable in the differential diagnosis, since it can demonstrate typical morphological features of the underlying process.     

Aneurysmal bone cyst of the temporal bone

Summary Aneurysmal bone cysts occurring within the calvarium are uncommon. The following case report describes the radiological and pathological findings of a temporal bone aneurysmal bone cyst with intra- and extracranial manifestations. The pertinent literature is reviewed.     

后颅窝囊肿的CT－MR影像学

目的：本文目的是对后颅窝囊肿的ＣＴ－ＭＲ影像学的诊断作用进行评价。材料与方法：１２例后颅窝囊肿的ＣＴ和ＭＲ影像表现进行了分析，探讨了其与临床表现和类型的相关性。结果：本组病例包含Ｄａｎｄｙ－Ｗａｌｋｅｒ囊肿（５例）、蛛网膜囊肿（３例）和巨枕大池（４例），ＣＴ和ＭＲ都可提供无创性检测手段。结论：ＣＴ和ＭＲ二者对后颅窝囊肿的诊断均有效，但在显示病变的性状、大小和轮廓方面，ＭＲ比ＣＴ稍胜一筹     

Telangiectatic osteosarcoma: radiologic-pathologic comparison

PURPOSE: To describe the imaging characteristics of a large series of telangiectatic osteosarcomas with pathologic findings for comparison. MATERIALS AND METHODS: The authors retrospectively reviewed 40 pathologically confirmed telangiectatic osteosarcomas. Patient demographics and images from radiography (n = 36), bone scintigraphy (n = 17), angiography (n = 4), computed tomography (CT) (n = 25), and magnetic resonance (MR) imaging (n = 27) were evaluated by three authors in consensus for lesion location, size, and intrinsic characteristics. There were 27 men (68%) and 13 women (32%) in the study, with an age range of 4-83 years (mean age, 24 years). RESULTS: Lesions frequently affected the femur, tibia, and humerus. Radiographs showed geographic bone lysis, a wide zone of transition, and matrix mineralization. CT demonstrated low attenuation, MR demonstrated high signal intensity on T2-weighted images, and both demonstrated hemorrhage, which simulated the appearance of aneurysmal bone cyst. Viable sarcomatous tissue surrounding hemorrhagic and/or necrotic regions was best seen at contrast material-enhanced CT and MR imaging, with thick peripheral, septal, and nodular enhancement in all cases. Subtle matrix mineralization in this viable tissue was best seen at CT. An associated soft-tissue mass was also seen in 19 of 25 cases (76%) at CT and in 24 of 27 cases (89%) at MR imaging. CONCLUSION: CT and MR imaging findings of telangiectatic osteosarcoma often include thick nodular tissue (and matrix mineralization at CT) in a largely hemorrhagic and/or necrotic osseous lesion with an associated soft-tissue mass, which allows distinction from aneurysmal bone cyst.     

Benign bone tumors and tumor-like lesions: value of cross-sectional imaging

This article reviews the role of CT and MR imaging in the diagnosis of benign bone tumors and tumor-like lesions of bone with with regard to differential diagnosis, the assessment of tumor-related complications, and the detection of postoperative recurrence. Indications for cross-sectional imaging of specific lesions, including osteoid osteoma, osteoblastoma, enchondroma, osteochondroma, intraosseous lipoma, hemangioma, giant cell tumor, aneurysmal bone cyst, simple bone cyst, and eosinophilic granuloma, are discussed, and advantages and disadvantages of the different imaging modalities are illustrated on the basis of pathologically confirmed cases.     

Serial MR imaging of pineal cysts: implications for natural history and follow-up

OBJECTIVE: The purpose of this study was to examine the frequency of change in size of pineal cysts on serial MR studies. MATERIALS AND METHODS: Thirty-two patients (19 females, 13 males) with a diagnosis of pineal cyst at any time who underwent brain MR imaging more than once in a period of at least 6 months were identified by computerized search of radiology reports. Four patients underwent MR imaging to follow up pineal cysts, whereas the remaining patients were imaged for a variety of indications, including intracerebral neoplasms. Measurements of maximal cyst dimension on both initial and latest follow-up studies were obtained in all patients, and cyst volumes were calculated in 23 patients. RESULTS: Length of follow-up ranged from 6 months to 9 years. All cysts were considered incidental and none were treated. Maximal cyst dimensions ranged from 0.5 to 2.2 cm. On average, there was no significant change in cyst volume. The maximal dimension of the cyst did not change in 24 (75%) of 32 patients. Two cysts resolved completely on follow-up, three cysts decreased by 2-4 mm, two cysts enlarged by 2-3 mm, and one cyst formed and grew to 1.2 cm. CONCLUSION: Whereas the size of pineal cysts as a whole remained unchanged on serial MR studies, cysts may either form or involute in individual patients. Small increases in cyst size did occur but were not associated with specific clinical findings. These findings suggest that typical pineal cysts may be followed up on a clinical basis alone rather than on imaging.     

Sonographic detection of Baker's cysts: comparison with MR imaging

OBJECTIVE: The objective of this study was to assess the ability of sonography to reveal Baker's cysts using MR imaging as a gold standard. MATERIALS AND METHODS: The study group consisted of 36 consecutive knees in 36 patients evaluated with both MR imaging and sonography. Inclusion criteria included axial proton density-weighted or T2-weighted MR images, a sonography report that documented the evaluation of the popliteal region of the knee, and sonographic and MR images that were available for review. The MR images were retrospectively reviewed for the presence of Baker's cyst (fluid signal between the semimembranosus and medial gastrocnemius tendons). Sonography reports were compared with the MR imaging results. The sonographic images were also retrospectively reviewed to determine whether any characteristic findings on sonography were significantly associated with the presence of Baker's cyst on MR imaging. RESULTS: Retrospective review of MR images revealed 21 Baker's cysts, one myxoid liposarcoma, one meniscal cyst, and 13 examinations with normal findings. The sonography reports revealed that the 21 Baker's cysts were correctly diagnosed, whereas the meniscal cyst and myxoid liposarcoma were misdiagnosed as Baker's cysts. Retrospective review of sonographic images showed a 100% sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the diagnosis of Baker's cyst when hypoechoic or anechoic fluid was present between the semimembranosus and medial gastrocnemius tendons. No other sonographic characteristics were significant. CONCLUSION: Identification of fluid between the semimembranosus and medial gastrocnemius tendons in communication with a posterior knee cyst indicates Baker's cyst with 100% accuracy.     

Echography for the diagnosis of aneurysmal bone cysts

Aneurysmal bone cysts are benign tumors which are likely to recur. While growing, they cause severe osteolysis, able to balloon the bone and to thin the cortex. The latter is reduced to a thin bone shell, and sometimes completely interrupted. Tumor mass can spread into the surrounding soft tissues as in other bone tumors, especially malignant ones, which are often misdiagnosed. Whether the cortex is interrupted or only thinned, an acoustic window is obtained which allows an easy study of tumor mass with US. Seven patients were examined, who presented lytic lesions of different bones, produced by aneurysmal cysts. US allowed the expansile lesion to be detected, and its size to be estimated. Moreover, US pattern of the lesion could be determined, which appeared both solid and liquid. A few minutes after beginning the examination, fluid levels could be observed to appear, which are typical of this condition, as both CT and MR imaging demonstrate both in vivo and in vitro. Thus US, thanks to its short execution time, low cost and non-invasiveness, can be considered as the second-step exam, after plain film, in the diagnosis of aneurysmal bone cyst.     

Case report 748

A case of chondroblastoma associated with an aneurysmal bone cyst has been described. The radiographic appearance of the lesion understandably reflects the combined features of both tumors. Up to one-half of all cases of aneurysmal bone cysts are found in association with other tumors, benign or malignant, and up to 15% of chondroblastomas are combined with an aneurysmal bone cyst (4).