Differential diagnosis of dumbbell lesions associated with spinal neural foraminal widening: imaging features

Computed tomography (CT) and magnetic resonance imaging (MRI) reliably demonstrate typical features of schwannomas or neurofibromas in the vast majority of dumbbell lesions responsible for neural foraminal widening. However, a large variety of unusual lesions which are causes of neural foraminal widening can also be encountered in the spinal neural foramen. Radiologic findings can be helpful in differential diagnosis of lesions of spinal neural foramen including neoplastic lesions such as benign/malign peripheral nerve sheath tumors (PNSTs), solitary bone plasmacytoma (SBP), chondroid chordoma, superior sulcus tumor, metastasis and non-neoplastic lesions such as infectious process (tuberculosis, hydatid cyst), aneurysmal bone cyst (ABC), synovial cyst, traumatic pseudomeningocele, arachnoid cyst, vertebral artery tortuosity. In this article, we discuss CT and MRI findings of dumbbell lesions which are causes of neural foraminal widening.     

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。     

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。     

Tumor-like lesions

Tumor-like bone lesions include various conditions of a non-neoplastic nature originating from or affecting the bone as solitary or sometimes multiple bone lesions. This review discusses the most important cystic tumor-like lesions, such as simple bone cyst, aneurysmal bone cyst, intraosseous ganglion, epidermoid cyst and subchondral cyst. MR is the most sensitive method of detection, and is the most accurate in depicting the extent of involvement of these lesions. MR signal characteristics may aid in differential diagnosis. Conventional radiographs are often more specific with respect to the underlying histopathology.     

CT and MRI in spinal meningeal cyst. Report of a case

A case of meningeal cyst of the spinal canal in the lumbosacral region is described. A CT scan showed a soft tissue mass associated with bone erosion. Myelography and computerised tomographic myelography revealed a cyst filling with contrast and thus CSF containing. The diagnosis of meningeal cyst was confirmed in a non-invasive way by MRI showing a mass with the same signal intensities as CSF on both T1 and T2 weighted images. Final characterisation of meningeal cysts in one of the three categories comprising spinal extradural meningeal cyst without spinal nerve root fibers (type I), spinal extradural meningeal cyst with spinal nerve root fibers (type II) and intradural meningeal cyst (type III) is impossible without operative inspection and histological examination.     

Morphological analysis of subchondral talar cysts on microCT

Purpose

Osteochondral talar defects often present in conjunction with subchondral bone cysts. The exact aetiology of these cysts is unknown. Recently was shown in a computational bone model that pressurized fluid and osteocyte death could lead to cyst growth, through mechanoregulated bone adaptation. However, a difference in cyst morphology was present between the mechanisms. The purpose of this study was to evaluate and compare the cyst morphology of human cadaveric tali by using microCT with the morphological simulation results previously reported.

Materials and methods

Sixty-six fresh-frozen human cadaveric tali were screened in a regular CT for subchondral bone cysts, radiologically defined as unexpected rounded radiolucent area. Subsequently, the tali with a cyst were scanned in a microCT. The shape of the cysts, the presence of an opening through the subchondral bone plate, and the bone volume fraction around and next to the cyst were analysed.

Results

In total, six tali were found to have a single cyst. Four cysts had an irregular shape, and two cysts were rounded. A clear opening from the cyst through the subchondral bone plate was found (diameter 0.5–1.7 mm) in four cysts. The bone volume fraction was higher (p = 0.025) around the cyst then next to the cyst.

Conclusions

The morphological findings that we found are only compatible with the previously reported simulation results of cyst growth in response to pressurized fluid, or pressurized fluid in combination with osteocyte death. It is therefore most likely that pressurized fluid plays a role in the pathoaetiology of cyst growth. A better understanding of cyst growth may improve treatment and prevent further cyst formation.     

Arachnoid cyst of the frontal part of the temporal lobe producing exopthtalmos CT and MRI evaluation

Twenty-three patients with an arachnoid cyst in the frontal part of the temporal bone, which produced exopthtalmos, were evaluated with CT and MRI. The majority of the patients had the peak of the bowing of the bony orbit wall in the posterior third (20/23) and only three in the middle. Arachnoid cyst are classified as small (13/23), medium (5/23) or large (5/20) size. Exopthtalmos are also classified as mild, moderate or large. CT and MRI clearly revealed the exopthtalmos, the bone remodelling process and the relationship of the orbit muscles, optic nerve and posterior bony wall of the orbit.     

基于CT三维重建分析距骨软骨下骨囊肿形态学及分布特点

目的:通过CT三维重建分析距骨软骨下骨囊肿的形态学及分布特点。方法:在天津医院影像报告数据库中检索2015—2020年经踝关节或足部CT扫描后诊断为距骨软骨下骨囊肿患者176例,其中男77例,女99例;年龄14~84岁［（56.1±14.0）岁］。通过Mimics 20.0软件三维重建距骨及囊肿区域后,构建田字解剖网格...     

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.     

囊肿内注射醋酸氢化可的松治疗手术后复发性骨囊肿的X线表现

目的：探讨囊肿内注射醋酸氢化可的松治疗手术后复发性骨囊肿的Ｘ线表现。材料和方法：５例手术后复发性骨囊肿穿刺及醋酸氢化可的松注射法以Ｘ线表现为指标，定期观察、治疗。结果：在治疗过程中，Ｘ线表现为云雾状、木棉状及骨瘢痕征象。经过２～１１年的随诊，５例完全治愈。结论：Ｘ线表现为骨瘢痕征象，是穿刺注射治愈手术后复发性骨囊肿的主要影像学特征。     

跟骨病变的影像学诊断

目的评价跟骨病变的影像学表现。资料与方法回顾性分析经穿刺和手术病理证实的25例跟骨病变影像学表现,其中7例感染性病变(松毛虫感染1例,慢性骨髓炎3例,Reiter’s病1例,结核2例),14例良性肿瘤和肿瘤样病变(骨囊肿4例,动脉瘤样骨囊肿3例,成软骨细胞瘤、血管瘤、内生软骨瘤、软骨黏液样纤维瘤、巨细胞瘤、巨细胞瘤伴动脉瘤样骨囊肿和脂肪瘤各1例),4例恶性骨肿瘤(骨肉瘤和软骨肉瘤各2例)。25例均行X线平片检查,16例行CT检查,8例行MRI检查。结果14例良性肿瘤和肿瘤样病变中11例发生于跟距关节下方,部位较具特征性。感染性病变和良、恶性骨肿瘤影像表现各异,具有各自的相对特征性。结论结合病变部位和平片、CT及MRI综合表现可对跟骨病变进行比较准确的定性。     

血管异常扩张性骨囊肿——对动脉瘤样骨囊肿命名及归属的商榷

本文报告11例血管异常扩张性骨囊肿,其病理特点是静脉动脉异常扩张引起的骨膨胀,原命名为动脉瘤样骨囊肿并不符合其病理改变。并对其归属及分类进行了讨论。     

Prevalence, extension and characteristics of fluid-fluid levels in bone and soft tissue tumors

The purpose of this study was to determine the prevalence, extension and signal characteristics of fluid-fluid levels in a large series of 700 bone and 700 soft tissue tumors. Out of a multi-institutional database, MRI of 700 consecutive patients with a bone tumor and MRI of 700 consecutive patients with a soft tissue neoplasm were retrospectively reviewed for the presence of fluid-fluid levels. Extension (single, multiple and proportion of the lesion occupied by fluid-fluid levels) and signal characteristics on magnetic resonance imaging of fluid-fluid levels were determined. In all patients, pathologic correlation was available. Of 700 patients with a bone tumor, 19 (10 male and 9 female; mean age, 29 years) presented with a fluid-fluid level (prevalence 2.7%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included aneurysmal bone cyst (ten cases), fibrous dysplasia (two cases), osteoblastoma (one case), simple bone cyst (one case), telangiectatic osteosarcoma (one case), “brown tumor” (one case), chondroblastoma (one case) and giant cell tumor (two cases). Of 700 patients with a soft tissue tumor, 20 (9 males and 11 females; mean age, 34 years) presented with a fluid-fluid level (prevalence 2.9%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included cavernous hemangioma (12 cases), synovial sarcoma (3 cases), angiosarcoma (1 case), aneurysmal bone cyst of soft tissue (1 case), myxofibrosarcoma (1 case) and high-grade sarcoma “not otherwise specified” (2 cases). In our series, the largest reported in the literature to the best of our knowledge, the presence of fluid-fluid levels is a rare finding with a prevalence of 2.7 and 2.9% in bone and soft tissue tumors, respectively. Fluid-fluid levels remain a non-specific finding and can occur in a wide range of bone and soft tissue tumors, both benign and malignant. Therefore, they cannot be considered diagnostic of any particular type of tumor, and the diagnosis should be made on the basis of other radiological and clinical findings.     

Primary and secondary aneurysmal bone cyst: a radiological study of 75 cases

Radiological findings in 75 cases of aneurysmal bone cyst were analyzed. Sixty-five per cent were primary or simple and 35% were secondary, the aneurysmal bone cyst being combined with other osseous lesions. A primary aneurysmal bone cyst can be diagnosed with a high degree of certainty, but only 20% of secondary forms had the radiological appearance of aneurysmal bone cyst; in the other 80% the associated lesion dominated the radiological picture, particularly when it was malignant. In the secondary form a small biopsy specimen may show the features of aneurysmal bone cyst only; without radiological assistance a concomitant malignant lesion may be missed. Therefore, there must be close collaboration between the radiologist and and the pathologist.     

Solitary (unicameral) bone cyst

The fallen fragment sign is a prominent radiologic feature in a minority of cases of unicameral bone cyst (20% in this series). This sign is always associated with pathologic fracture. Intramedullary fracture fragments may be single or multiple and may or may not be entirely dislodged from overlying periosteum. The finding appears limited to unicameral bone cysts in patients with open physes. When present, the fallen fragment is a pathognomonic finding as it defines the interior of the cyst as nonsolid. This is particularly helpful in cases where absence of the cyst wall secondary to fracture can simulate an intramedullary malignancy with cortical erosion.     

A case of aneurysmal bone cyst in father and son

The authors report a familial case of primary aneurysmal bone cyst in father and son, affecting both at the same location at nearly the same age. This fact again raises the speculation of a genetic link as another factor in the pathogenesis of aneurysmal bone cyst.     

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。     

Bone tumor mimics: avoiding misdiagnosis

Whether discovered incidentally or as part of a focused diagnostic evaluation, the finding of a benign osseous lesion that has radiologic features resembling a bone tumor is not uncommon. Some of the more common benign and nonneoplastic entities that can sometimes be confused with tumors are the following: cortical desmoid, Brodie abscess, synovial herniation pit, pseudocyst, enostosis, intraosseous ganglion cyst, fibrous dysplasia, stress fracture, avulsion fracture (healing stage), bone infarct, myositis ossificans, brown tumor, and subchondral cyst. Accurate diagnosis and management of these lesions require a basic understanding of their epidemiology, clinical presentations, anatomic distributions, imaging features, differential considerations, and therapeutic options. This in-depth review of 13 potential bone tumor mimics will assist the radiologist in correctly identifying these benign lesions and in avoiding misdiagnosis and related morbidity. This review will also aid the radiologist in making appropriate recommendations to the referring physician for management or further imaging.     

基底细胞痣综合征影像表现

目的:探讨基底细胞痣综合征(BCNS)的临床及影像学表现.方法:搜集6例经病理和临床综合诊断证实的BCNS患者的临床和影像资料进行回顾性分析,总结分析其影像学表现.结果:6例(6/6)均有颌骨囊肿和颅内异常钙化灶,分别伴有皮肤多发基底细胞痣或手掌、足底点状凹陷4例(4/6),脊椎侧突或椎体融合4例(4/6)、肋骨分叉3例(3/6),透明隔囊肿1例(1/6),特殊面征4例(4/6),口腔症状6例(6/6),生殖系统发育异常或肿瘤2例(2/6),双眼分离性斜视1例(1/6).结论:BCNS以颌骨囊肿为主要表现,常伴有其他器官的变异或病症,影像诊断为该病的确诊提供重要依据,对临床制定治疗方案具有重大临床意义.     

Contrast examination as a prognostic factor in the treatment of solitary bone cyst by cortisone injection

Local injection of radiopaque medium demonstrated the presence of intracystic fibrous septa in 13 patients with solitary bone cyst. Contrast examination was helpful in predicting the response of solitary bone cysts to treatment by injection of methylprednisolone-acetate (MPA). As the number of septa increased, an increased difficulty in obtaining an equal distribution of MPA inside the cyst and a higher incidence of incomplete healing of the cyst was encountered.