Radiation-induced sarcoma of bone: CT findings in 19 cases

We reviewed the CT findings in 19 cases of radiation-induced sarcoma of bone. The latent period before development of the sarcoma ranged from 5 to 50 years (mean, 17 years). In all 19 lesions, a soft-tissue extraosseous component was seen on CT, and 18 of them had associated bone destruction. Expansion of the affected bone and tumor-matrix mineralization each were present in 10 patients, but occurred together in only five patients. Periosteal reaction was seen in five patients, one of whom had an associated fracture. Radiation osteitis could not be identified on CT scans in the affected bone of any of the patients when tumor was present, but it was present in contiguous bone in two patients and had been shown 6 years before tumor became apparent in the affected bone in one other patient. Radiation-induced sarcoma of bone should be considered when bone destruction and an associated soft-tissue mass are shown on CT, or when changes occur in the appearance of previously stable irradiated bone.     

Langerhans' cell histiocytosis of the temporal bone in pediatric patients: imaging and follow-up

OBJECTIVE: The purpose of this study was to review the initial clinical and radiologic manifestations and the follow-up of pediatric patients with Langerhans' cell histiocytosis affecting the temporal bone. MATERIALS AND METHODS: We retrospectively studied 14 patients with Langerhans' cell histiocytosis affecting the temporal bone. All patients were examined initially and sequentially with CT. In six patients, MR imaging was also done. RESULTS: Temporal bone involvement was the initial form of presentation in 12 patients. In eight patients, temporal bone involvement presented as an isolated manifestation, and in four it was associated with multisystemic involvement. In the remaining two patients, temporal bone involvement appeared during the course of the Langerhans' cell histiocytosis. Bilateral involvement was seen in four patients. In two patients, the temporal bone was affected only at the petrous apex. CT showed destruction of bone in all 14 patients and an associated soft-tissue homogeneous mass after injection of i.v. contrast material in 12 patients. CT showed a heterogeneous appearance of the soft-tissue mass in two patients. The average period of follow-up was 5 years. In seven of the 14 patients, the disease had a satisfactory evolution in which the bony lesions of the temporal bone reossified and remodeled over the course of a year. CONCLUSION: In Langerhans' cell histiocytosis, involvement of the temporal bone is usually seen on radiographs as extensive lytic lesions associated with soft-tissue masses. The lesions that remit show early disappearance of the soft-tissue mass, followed by reossification and remodeling of the involved bone. Patients with limited initial involvement of the temporal bone have a better prognosis on long-term follow-up than do patients with the multisystemic form.     

介入栓塞治疗在骨与软组织肿瘤中的应用

目的 探讨介入在骨和软组织肿瘤临床治疗中的价值.方法 对28例经病理证实的骨与软组织肿瘤患者行选择性血管造影、动脉内灌注化疗和(或)栓塞治疗;观察治疗后临床、病理改变.结果 动脉灌注化疗和(或)栓塞治疗后23例疼痛缓解或消失;19例软组织消肿,肿瘤缩小;22例在介入治疗后1周内又接受手术治疗并经病理检查,显示瘤细胞不同程度变性、坏死、液化,以并用栓塞治疗者更为显著.肢体肿瘤患者66.4%(10/15)行保肢手术.结论 介入治疗是骨与软组织肿瘤的有效治疗方法,值得在临床上推广使用.     

Primary malignant lymphoma of the maxillary sinus: CT and MRI

We reviewed the CT and MRI of seven patients with primary malignant lymphoma of the maxillary sinus to find if there are characteristic imaging findings suggestive of the disease. The images were analysed for appearance, size, signal, internal characteristics, extent of tumour, bone change and lymph node enlargement. In two patients, the tumour first presented with mucosal thickening. In the remaining five, the tumours were an expansile mass 4–6 cm in diameter at the time of detection. Although it was difficult to distinguish tumour from mucosa or obstructed fluid on CT, T2-weighted MRI enabled us to separate tumour from normal mucosa or fluid. In two patients, the tumours were heterogeneous. Calcification and haemorrhage were observed in one patient. Periantral soft-tissue infiltration was always present, even when tumour appeared as slight mucosal thickening. Posterior extension was seen in all patients. Permeative and lytic bone destruction accompanied most cases of periantral soft-tissue infiltration; mixed destruction and sclerosis was also observed. Mucosal thickening with periantral soft-tissue infiltration may suggest malignant lymphoma of the maxillary sinus in its early form. Various types of bone change may accompany the periantral soft-tissue infiltration. Received: 25 January 1999 Accepted: 21 July 1999     

Role of angiography in limb-tumor surgery.

Routine preoperative angiograms obtained in 97 consecutive patients with bone and soft-tissue tumors of the extremities were retrospectively reviewed to determine the role of angiography in surgical planning. Some degree of major vessel displacement was demonstrated in 51 patients. Encasement of major vessels, which precluded limb-salvage surgery, was seen in five of 76 bone tumors and in three of 21 soft-tissue tumors. All five patients with osteochondromas had associated vessel occlusion or compromise. For surgical planning, the demonstration of adequate anastomoses in the arches of the hands and feet is important, as branches of brachial and popliteal arteries may have to be sacrificed during limb-tumor surgery. Angiographic findings indicated or supported the need for a vascular surgeon in five cases in this series. Preoperative angiography provides important information with regard to the status of the vasculature and therefore is essential in the management of bone and soft-tissue tumors of the extremities.     

Osseous change adjacent to soft-tissue hemangiomas of the extremities: correlation with lesion size and proximity to bone

OBJECTIVE: The purpose of this study was to describe the findings of MR imaging and radiographic changes that occur in osseous structures adjacent to soft-tissue hemangiomas of the extremities and to correlate them with patient symptomatology, the size of the hemangiomas, and their proximity to adjacent bone. MATERIALS AND METHODS: We retrospectively reviewed the radiographs and MR images of 35 patients with soft-tissue hemangiomas of the extremities. The pattern and extent of the osseous change were categorized as periosteal, cortical, or medullary. Symptomatology, size, and proximity of the hemangioma to the adjacent bone were compared with the presence or absence of osseous change. Statistical analysis was performed using the Student's t test. RESULTS: Osseous change was noted on radiographs in 13 (37%) of 35 patients and on MR images in 11 (31%) of 35 patients with a total of 14 patients (40%) showing osseous change on at least one study. Periosteal change was present in eight (23%) of 35 patients; cortical change, in 11 (31%) of 35 patients; and medullary change, in 10 (29%) of 35 patients. Direct contact between the soft-tissue hemangioma and the adjacent bone was seen in 13 of 14 patients with osseous change. In those patients without osseous change, the average distance between the soft-tissue hemangioma and bone was 1.06 cm (range, 0-4 cm). No correlation was found between symptoms and the presence of osseous change. CONCLUSION: Soft-tissue hemangiomas of the extremities frequently result in adjacent osseous change that can be categorized as either periosteal, cortical, or medullary. Only medullary changes correspond with hemangioma size, whereas all three categories of change correlate with the proximity of the hemangioma to the adjacent bone. The presence of osseous change does not correlate with patient symptomatology.     

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.     

Cholesterol granuloma in the middle cranial fossa: report of two cases

We report two cases of cholesterol granuloma in the middle cranial fossa. On CT the lesions appeared as a nonspecific, nonenhancing soft-tissue mass with bone erosion. On MRI they were seen as areas of high signal intensity surrounded by a low-intensity peripheral zone on both T1- and T2-weighted images. Cholesterol granuloma is thought to occur when pneumatised cellsin the temporal bone become obstructed. Although this lesion usually occurs in the petrous bone, it can extend to the middle cranial fossa. The diagnosis and surgical management are discussed.     

Permanent Proplast temporomandibular joint implants: MR imaging of destructive complications

We studied the radiologic and pathologic changes in 30 patients (34 joints) in which there were locally destructive bone and soft-tissue complications associated with previously inserted permanent temporomandibular joint (TMJ) Proplast-Teflon implants. The cases were selected as representative examples of patients with failed Proplast interpositional arthroplasty, in whom images of the TMJ were obtained with conventional radiography, tomography, and MR, and in whom both surgical and histologic findings were available. Clinical indications for imaging included joint pain, restricted joint motion, crepitus, preauricular swelling, regional lymphadenopathy, malocclusion either acquired or changed since implant surgery, and facial deformity. Surgery was then performed for the purposes of implant retrieval and joint debridement because of destructive soft-tissue and osseous changes observed from the imaging analysis in conjunction with significant clinical signs and symptoms. The pathologic changes, observed 4-54 months after implant surgery, included a destructive foreign-body-type granuloma and avascular necrosis of the mandibular condyle and condylar neck. Our findings suggest that MR is useful in the detection and evaluation of destructive complications that may accompany failed Proplast-Teflon implants in the TMJ. MR is superior to conventional radiography and tomography in detecting soft-tissue lesions and avascular necrosis of bone. Tomography more accurately delineates soft-tissue calcifications and cortical margins of osseous structures.     

Desmoplastic fibroma of bone: radiographic analysis

Desmoplastic fibroma (DF) of bone is a rare, nonmetastasizing but locally aggressive tumor that has been discussed infrequently in the radiology literature. The radiographs from 107 previously published cases of DF and seven cases from the authors' institution were analyzed to better understand and define its radiographic characteristics. DF was most common in the mandible, pelvis, and femur. A geographic pattern of bone destruction, with a narrow zone of transition and nonsclerotic margins, was seen in 80 (96%) patients with intraosseous DF for whom radiographs were available (83 patients). Internal pseudotrabeculation was seen in 76 (91%). Although widening of the host bone due to gradual apposition of periosteal new bone was common, occurring in 74 (89%) patients, distinct periosteal new bone occurred in only two (2%) patients with DF of intraosseous origin. The cortex was breached in 23 (28%) patients. Three cases of DF arising in the periosteum were identified and were differentiated radiographically from desmoid tumors of intraosseous or soft-tissue origin.     

CT in pyogenic osteomyelitis of the spine

Six patients with bacteriologically proven pyogenic osteomyelitis of the spine were followed serially with computed tomography (CT). Initial evaluation of the involved vertebral bodies and adjacent soft tissues showed a drop in CT numbers when compared to normal cancellous bone and soft tissues. A soft-tissue mass was seen in all cases. After appropriate antibiotic therapy, all six patients showed an increase in bone density and a diminution of the soft-tissue mass (p less than 0.05). Five of the six patients showed a further decrease in soft-tissue CT numbers.     

Imaging features of primary lymphoma of bone

OBJECTIVE: Our objective was to describe the imaging appearances of primary lymphoma of bone, including conventional radiographic, scintigraphic, CT, and MR imaging features. MATERIALS AND METHODS: We retrospectively reviewed 237 pathologically proven cases of primary lymphoma of bone. Evaluation included patient age, sex, lesion location, and pattern of bone destruction. Pathologic type, periosteal reaction, sequestrum, soft-tissue mass, extension across joints, and pathologic fracture were also noted. RESULTS: The study population included 151 males and 86 females (ratio 1.8:1; range, 2-88 years; mean age, 42 years). Common locations were the distal femoral diametaphysis; proximal metadiaphysis of the tibia, femur, and humerus; and femoral mid shaft. Long bones were involved more often than flat bones (71% versus 22%). Common appearances were a lytic (70%) or mixed-density (28%) lesion with most cases showing a permeative or moth-eaten pattern (74%). Periosteal reaction was seen in 58% of the long bones. Sequestra were found in 37 patients (16%). Soft-tissue masses were present in 113 patients (48%). Extension across joints was seen in nine patients (4%). Pathologic fractures occurred in 53 patients (22%). Radionuclide (n = 56), CT (n = 45), and MR (n = 20) features were usually nonspecific. Pathologic types included non-Hodgkin's (n = 223) and Hodgkin's (n = 14) lymphoma. CONCLUSION: Primary lymphoma of bone most often involves the diametaphysis of a major long bone and has an aggressive pattern of lytic bone destruction and associated soft-tissue mass. CT and MR imaging can suggest the diagnosis, particularly when a large soft-tissue mass and abnormal marrow attenuation or signal intensity is seen without extensive cortical destruction.     

MR imaging characteristics in primary lymphoma of bone with emphasis on non-aggressive appearance

Purpose To assess the heterogeneity of magnetic resonance (MR) imaging characteristics in primary lymphoma of bone (PLB), in particular the non-aggressive appearance. Subjects and methods In a retrospective study, MR imaging features were analyzed in 29 patients with histologically proven PLB. The following parameters were evaluated: tumor size, bone marrow and extension into soft tissues, signal characteristics of bone marrow and soft-tissue components, including enhancement, and involvement of cortical bone (complete disruption, focal destruction, permeative destruction and cortical thickening). Results PLB presented with extension into the soft tissue in 22 (76%) of 29 patients, was only subtle in three of these 22 patients, and was absent in seven patients. Signal intensity (SI) of the soft-tissue part was most frequently homogeneously isointense with muscle on T1-weighted images (90%) and high on T2-weighted images (91%). Enhancement was predominantly homogeneous and diffuse (82%). In 93% of patients cortical bone appeared abnormal: among those patients complete cortical disruption was seen in 28%, with extension into soft tissues in all but one patient; a permeative pattern of destruction was present in 52% of patients, 66% of these had an associated soft-tissue mass. Two patients with normal-appearing cortical bone had no extension into soft tissues. In two patients focal cortical destruction was noticed; in one patient cortical bone was homogeneously thickened, and in one patient PLB was selectively localized within the cortical bone. SI of the bone marrow tumor component was more frequently heterogeneous (in 54%), compared with the soft-tissue component, being high on T2-weighted images in 89%, intermediate in 7% and low in 4%. Similarly, enhancement was heterogeneous in 59%. Conclusion The MR imaging appearance of PLB is variable. In 31% of PLB patients, the tumor was intra-osseous, with linear cortical signal abnormalities or even normal-appearing or thickened cortical bone without soft-tissue mass, and, as such, PLB may not infrequently look non-aggressive on MR imaging.     

Ossifying lipoma of the thigh

Lipomas are common soft-tissue tumours that are usually found in the subcutaneous adipose tissue. Occasionally, they may contain mesenchymal elements other than adipose tissue, including osseous components. These ossifying lipomas are usually located near or within bone, and it is very rare for a lipoma with no connection to bone to contain mature osseous tissue. We describe a case of a symptomatic ossifying intramuscular lipoma of the thigh.     

Heterotopic bone formation (myositis ossificans) and lower-extremity swelling mimicking deep-venous disease

A quadriplegic patient with a swollen leg was suspected of having deep-venous thrombosis, and was studied with radionuclide venography (RNV) and contrast venography. Focal narrowing of the femoral vein, seen on RNV, was due to extrinsic compression. Although soft-tissue radiographs were normal, Tc-99m diphosphonate imaging established the diagnosis of early heterotopic bone formation (myositis ossificans), which was responsible for the venous compression. Clinically this inflammatory process can mimic deep-venous thrombosis, and should be considered in evaluating patients at risk for both heterotopic bone formation and deep-venous thrombosis.     

High-resolution 3DFT MR imaging of the endolymphatic duct and soft tissues of the otic capsule

This study compares the visualization of otic capsule anatomy by thin-section three-dimensional Fourier transformation (3DFT) MR imaging with that by high-resolution CT. The osseous margins of the otic capsule are delineated by high-resolution CT, while MR displays the soft-tissue structures. Routine two-dimensional Fourier transformation (2DFT) spin-echo MR techniques have been limited by slice thickness and signal to noise. Previous longer TE 3DFT gradient-echo MR images of the otic structures have been degraded by magnetic susceptibility effects, which limit spatial resolution and decrease signal to noise. These effects are especially prevalent in the otic capsule, where small soft-tissue structures interface with surrounding air and bone. We developed a high-resolution 3DFT MR technique to image five normal subjects. MR images were compared with high-resolution CT images of the same subjects. Axial, sagittal, and coronal 3DFT gradient-echo MR images with a short TR/TE and 15 degrees flip angle were acquired on a General Electric 1.5-T Signa unit using a 3-in. circular, receive-only surface coil. Axial, sagittal, and coronal 1.5-mm-thick contiguous high-resolution CT bone-algorithm images were obtained also. There was a high correlation between the MR and CT findings. The 3DFT MR images demonstrated significantly higher spatial resolution and soft-tissue detail than the high-resolution CT images did. For example, the endolymphatic duct was seen on twice the number of consecutive sagittal and axial MR slices. Other soft-tissue otic capsule structures routinely seen on the 3DFT MR images included the entire facial nerve, membranous labyrinth including cochlea, and tensor tympani muscle. This study demonstrates a new high-resolution 3DFT MR technique for visualizing the soft-tissue microstructures of the otic capsule and achieves a level of spatial resolution beyond that possible with high-resolution CT.     

Extraskeletal soft tissue masses of Langerhans’ cell histiocytosis

 Typically, soft-tissue involvement with Langerhans’ cell histiocytosis (LCH) is the result of extension from adjacent bone marrow. We present a patient who developed soft-tissue masses of LCH, which did not arise as a result of extension from bone marrow, but instead produced extrinsic cortical erosion, preserving the marrow signal on MRI.     

Computed tomographic analysis of the intratemporal facial nerve and facial nerve neuromas

High-resolution computed tomography (HRCT) has replaced multidirectional tomography in the detailed analysis of the temporal bone because of its excellent resolution of fine bony detail. Small soft-tissue masses not discernible on plain tomograms are easily seen using HRCT. Unsuspected early disease which has not caused recognizable bone erosion in also demonstrable by HRCT. Last but not least, the amount of radiation received by a patient as a result of HRCT is considerably less. We illustrate the normal course of the facial nerve through the temporal bone, its anatomical relationship to various adjacent structures, and the numerous branches given off during its course through the temporal bone. The clinical features of facial nerve neuromas (schwannomas) depend on their location and include facial nerve weakness or paralysis, otalgia or facial pain, hearing loss or imbalance, and loss of taste sensation. HRCT allows the identification of a soft-tissue mass along the course of the facial nerve, with its bony canal usually enlarged by the mass. Pressure erosion of the underlying bone is often noted and erosion of the ossicles may be demonstrated in the case of middle ear involvement. The importance of both clinical and radiological correlation cannot be overemphasized in the discovery of these tumors.     

Osteoblastoma: clinical and radiologic findings in 98 new cases

The data on 98 new patients with osteoblastoma were studied. The clinical features of pain, scoliosis, and neurologic deficit were largely consistent with those in previous reports. Osteoblastoma is usually a lytic lesion originating in the medulla of bones with matrix ossification and mild surrounding sclerosis. Osteoblastoma of the spine demonstrated better tumor delineation in the vertebrae, and a bony rim on the soft-tissue side was seen less frequently than previously observed. Osteoblastoma of the talus frequently appears as a blister on the surface of the bone and is accompanied by osteoporosis. In the hands and feet, the radiographic appearance is often very similar to that of aneurysmal bone cyst and giant cell tumor. In the skull it strongly resembles a button sequestrum of bone. The origin and extent of the tumor, the presence of matrix mineralization, and tumor delineation depicted as a thin bony shell are often better appreciated on computed tomographic (CT) scans. In addition, CT can demonstrate both edema and atrophy of the surrounding soft tissues. At magnetic resonance (MR) imaging, osteoblastoma demonstrates signal intensities similar to those of other bone neoplasms. In addition to the advantages offered by CT, MR imaging can help differentiate tumor tissue from accompanying edema.     

Computed tomography of acoustic neurinoma

Thirty-seven patients with 39 acoustic neurinomas were studied with computed tomography (CT). Six tumors (15%) were seen on the nonenhanced scans and infusion of contrast material demonstrated 23 more tumors. Ten tumors (26%) were not seen as soft-tissue masses on the enhanced CT scans. However, these same 10 cases yielded 4 ipsilateral abnormal internal auditory canals when viewed with a bone window. Findings suggestive of acoustic neurinomas were found in 85% of proven sites. Important factors in the CT diagnosis of acoustic neurinomas are good-quality, motion-free scans, contrast enhancement and analysis of bone detail.