Imaging findings in Mazabraud's syndrome: seven new cases.

OBJECTIVE: To present seven new cases of Mazabraud's syndrome with particular observations on the magnetic resonance imaging findings and a review of the literature. DESIGN AND PATIENTS: A multi-institutional retrospective review was performed on seven patients with confirmed Mazabraud's syndrome. The patient group was composed of six women and one man, ranging in age from 39 to 65 years, with a mean age of 53 years. RESULTS: Fibrous dysplasia was more often polyostotic ( n=6) and right-sided ( n=4). Fibrous dysplasia involved the femur in five cases. The soft tissue myxomas were multiple in four cases and were intramuscular in origin. The most commonly affected location was the thigh ( n=4). On computed tomography, myxomas were well-circumscribed, low-attenuation masses. On magnetic resonance images, the lesions were significantly low in signal intensity on T1-weighted images and high in signal intensity on T2-weighted images relative to adjacent skeletal muscle. Enhancement of the myxomas was heterogeneous with irregular, peripheral rim enhancement, and a variable degree of central enhancement depending on the abundance of solid myxoid tissue and bridging fibrous septa. CONCLUSIONS: Knowledge of Mazabraud's syndrome and the imaging appearance of intramuscular myxoma is important in order to avoid unnecessary biopsies of the osseous and soft tissue lesions. The unique features of this disorder allow discrimination from soft tissue malignancies such as sarcoma.

Magnetic resonance imaging features of allografts.

OBJECTIVE: To investigate the magnetic resonance imaging (MRI) features of allografts at various time intervals after surgery in patients with osteoarticular allografts. DESIGN AND PATIENTS: Sixteen patients who were treated with osteoarticular allografts and who were followed over time with MRI studies as part of their long-term follow-up were retrospectively selected for this study. T1-weighted images were obtained both before and after gadolinium administration along with T2-weighted images. All images were reviewed by an experienced musculoskeletal radiologist, with two other experienced radiologists used for consultation. Imaging studies were organized into three groups for ease of discussion: early postoperative period (2 days to 2 months), intermediate postoperative period (3 months to 2 years), and late postoperative period (greater than 2 years). RESULTS: In the early postoperative period, no gadolinium enhancement of the allograft was visible in any of the MR images. A linear, thin layer of periosteal and endosteal tissue enhancement along the margin of the allograft was visible in images obtained at 3-4 months. This enhancement appeared gradually to increase in images from later periods, and appears to have stabilized in the images obtained approximately 2-3 years after allograft placement. The endosteal enhancement diminished after several years, with examinations conducted between 6 and 8 years following surgery showing minimal endosteal enhancement. However, focal enhancement was noted adjacent to areas of pressure erosion or degenerative cysts. All the cases showed inhomogeneity in the marrow signal (scattered low signal foci on T1 with corresponding bright signal on T2), and a diffuse, inhomogeneous marrow enhancement later on. CONCLUSION: We have characterized the basic MRI features of osteoarticular allografts in 16 patients who underwent imaging studies at various time points as part of routine follow-up. We believe that the endosteal and periosteal enhancement observed on MRI during the first few months to 2 years following surgery represents vascular ingrowth and early skeletal repair. The zone of periosteal enhancement could also include the new bone laid on the surface of the allograft through which the soft tissues bind to the cortex. The exact reason for the inhomogeneity in the marrow signal, and the diffuse, inhomogeneous marrow enhancement is not clear. This may represent saponified and/or necrotic marrow fat interspersed with the fibrovascular tissue. The features noted here should provide radiologists with useful information regarding imaging characteristics they can expect to see in other allograft replacement patients.

Computer-based speech recognition as a replacement for medical transcription.

OBJECTIVE: We have implemented computerized speech recognition in a high-volume clinical setting using a newly developed commercial software system. This paper compares the performance of the computerized system with conventional transcription during a trial week followed by 3 months of routine clinical use. CONCLUSION: The speech recognition system was used for 97% of the cases during the trial week and 87% of cases during the months of continuous use. For a similar mixture of cases, no change occurred in the length of reports after introduction of the computerized system. Speech recognition decreased the time until the report became available by 99% and resulted in a substantial savings in transcription costs. We conclude that speech recognition by computer is practical in a high-volume clinical implementation.

Tuberculosis of contralateral costo-transverse joints.

We present a case of multifocal tuberculosis of contralateral costo-transverse joints. Even in countries where tuberculosis is common, extrapulmonary multifocal infection is uncommon. Furthermore, a bilateral, symmetric distribution is distinctly unusual. The index of suspicion for tuberculosis should increase when the patient is from a country where tuberculosis is endemic or when a history of AIDS is present.

Vertebral morphometry derived from digital images.

OBJECTIVE: We describe a method for capturing measurement data directly from digitized images using specialized software and high-resolution workstations. We have evaluated the reliability, accuracy, and reproducibility of this method in an international clinical trial involving vertebral morphometry. MATERIALS AND METHODS: Accuracy was determined using clinical radiographs measured with vernier calipers and a film phantom. Intra- and interobserver variabilities were assessed, and longitudinal reproducibility was evaluated. As part of the trial, spinal radiographs were collected from more than 200 international health care facilities and digitized at four screening centers. Digitized images were stored and sent to our central facility for morphometry and archiving. Timeliness and variability of the process were tracked. RESULTS: Relative accuracy was nearly 100%. Correlation with clinical measurements was high (r = .96; p < .05). The mean coefficient of variation for interobserver variability was 2%. Intraobserver variation was 3-5%. The coefficient of variation for longitudinal reproducibility ranged from 4% to 6%. After 9 months of operation, our trial included 9494 patients. Of approximately 36,000 radiographs, 98% passed quality review. Only 1% of vertebral levels were not measurable. Hardware and software problems were minimal. CONCLUSION: The use of digitized images for morphometry is accurate, reproducible, and convenient. When applied to a large-scale clinical trial, it offers unique advantages that may justify the cost and complexity that exceed those of conventional radiographs.

Surgical management of innominate giant cell tumor.

The surgical outcome for innominate giant cell tumors was reviewed in 7 patients; 6 (86%) were female patients and 1 (14%) was a male patient. The patients had an average age of 28.7 years (range, 16-42 years) and an average followup of 4.6 years (range, 2.0-7.3 years). Three tumors were in the ischiopubic region, 3 were acetabular, and 1 was iliosacral. The tumors ranged in size from 5 cm x 6 cm to 17 cm x 18 cm. All margins were intralesional. Reconstruction in 3 cases used osteoarticular acetabular allografts. The local recurrence rate was 3 of 7 (43%). Ischiopubic tumors accounted for all recurrences. Vascular invasion was seen in all patients who had a recurrence and only 1 patient without a recurrence. Patients with recurrences underwent subsequent resections and radiation therapy, and remain disease free at an average followup of 3.0 years (range, 0.8-4.2 years) after recurrence. There were no malignant, metastatic, or multicentric recurrences, and no patient died of disease or complications. Innominate giant cell tumor occurs most often in women and is associated with a high risk for local recurrence. Wide margins usually are not possible; intralesional margins are accepted in cases of limited accessibility or potential functional compromise.

Paracoccidioidomycosis of bones and joints. A clinical, radiologic, and pathologic study of 9 cases.

Paracoccidioidomycosis is a systemic fungal infection endemic to Central and South America. It is associated with a broad spectrum of clinical manifestations and has been classified into acute and chronic forms. The latter is the most common type and usually affects male agricultural workers in rural communities. The disease typically begins in the lungs producing varying degrees of parenchymal damage, and in a significant number of cases the organism spreads through bronchogenic, lymphatic, or hematogenous routes to involve 1 or more organs. Bone and joint infection is relatively uncommon and has not been well described in the English literature. Much of the information on this form of the disease has been derived from radiographic and autopsy studies on patients with severe or fatal infections in whom skeletal involvement was a minor or incidental finding. We describe our experience with 9 cases in which osteoarticular manifestations were the sole or 1 of the few major complications of the disease. All 9 patients were male, from 9 to 49 years of age (mean, 36.6 yr). Six were farmers. Evidence of visceral infection was present in 6 patients, in all of whom the lungs were considered the primary site of disease. The osteoarticular lesions were symptomatic in all cases, with the duration of symptoms ranging from 1 week to 2 years. The lesions were centered in bone in 2 cases: they manifested radiographically as circumscribed areas of lysis with or without a rim of sclerosis. The disease was centered in joints in 7 cases; the associated radiographic changes included evidence of joint effusion, periarticular bony erosions, and narrowing of the joint space. Biopsy of the involved skeletal site revealed compact or loose granulomas containing variable numbers of fungi. Although follow-up information was not available for all patients, those treated with TMP-SMX (and 1 patient who also received amphotericin B) and who were followed had prompt resolution of their signs and symptoms. Our findings substantiate some of what is known about the epidemiology of bone and joint involvement in chronic paracoccidioidomycosis. Our patients exhibited features of skeletal infection that have not been emphasized previously, however, including 1) frequent involvement of large joints or long bones of the extremities, 2) presentation with relatively rapidly developing musculoskeletal symptoms, and 3) manifestation as a solitary joint or bone lesion with or without concurrent clinically detectable pulmonary disease. Bone and joint paracoccidioidomycosis should be considered in the differential diagnosis in patients who have skeletal lesions with or without pulmonary involvement and have either lived in or traveled through endemic areas. Early diagnosis and treatment with antifungal medications can achieve an excellent outcome with limited local sequelae.

Calcific myonecrosis. A late sequela to compartment syndrome of the leg.

The clinicopathologic features of calcific myonecrosis are presented from results of an examination of 3 cases of this rare syndrome and review of the literature. Calcific myonecrosis is a painful, expansile, calcified mass that develops in muscle several decades after lower extremity trauma that typically has been associated with vascular injury. Plain radiographs show a well-defined and heavily calcified mass replacing the leg musculature. The calcifications are present in a thin, linear pattern and are organized around the periphery of the lesion. Smooth erosion of the adjacent bone may be present, whereas magnetic resonance imaging shows a heterogeneous signal with enhancement limited to the periphery of the mass. Pathologic features consist of a centrally cystic mass arising in muscle filled with friable, tan to dark red, soft debris. The cyst walls are firm and fibrous and contain many needle-like, elongated, calcified shards of necrotic tissue composed of hypocellular fibrous tissue with focal aggregates of hemosiderin-laden macrophages. The cyst contents are composed of necrotic skeletal muscle and acellular amorphous debris containing many cholesterol crystals, fibrin, and recent hemorrhage, including focal aggregates of organizing thrombus. The pathologic findings suggest that calcific myonecrosis might expand with time by virtue of recurrent intralesional hemorrhage into a chronic calcified mass that eventually becomes symptomatic. Surgical intervention is associated with a high rate of complication, particularly in cases in which intralesional procedures have been done.

CT-guided aspiration in potentially infected total hip replacements complicated by heterotopic bone.

Aspiration of the hip joint in the setting of a potentially infected total hip replacement is occasionally unsuccessful under fluoroscopic guidance because of periarticular heterotopic bone. Of 136 consecutive patients with total hip replacements who were referred to the radiology department for hip aspiration because of suspected infection, successful intraarticular needle placement was achieved in 132 (97%) under fluoroscopic guidance. In four (3%) cases, the attempted aspiration was unsuccessful because heterotopic bone prevented the needle tip from reaching the joint; a second attempt was performed successfully under CT guidance. CT confirmed that the anterior approach was completely blocked by heterotopic bone and that there was a gap in this bone elsewhere through which a needle could be passed into the joint. The increased cost of CT was modest because it was necessary in only a small percentage of patients.

Atypical lipomas, liposarcomas, and other fat-containing sarcomas. CT analysis of fat element.

The radiographic appearance of fat in and around soft tissue sarcomas was evaluated to assess the diagnostic potential of this finding. Based on the distribution of fat and other components, these tumors are classified into three types.

The value of contrast arthrography in assessing loosening of symptomatic uncemented total hip components.

Twenty-five patients with symptomatic uncemented total hip components were studied with contrast arthrography prior to surgical exploration. All but one had uncemented femoral stems and 16 had an uncemented acetabular component. As judged by the findings at surgery, on the femoral side the sensitivity, specificity, and accuracy of arthrography were 57%, 60%, and 58% respectively. There was a relatively high incidence of both false positives (17%) and false negatives (25%). On the acetabular side sensitivity, specificity, and accuracy were 29%, 89%, and 62.5%. False negatives were common (31%), while there was only one false positive. The results in this small series show that arthrography has distinct limitations in identifying the fixation status of uncemented total hip components.

Extensive skeletal metastases from chondrosarcoma without pulmonary involvement.

Among 251 patients who presented to our orthopedic oncology unit over the last 20 years with chondrosarcoma, we identified two patients with low to intermediate grade conventional chondrosarcoma who developed multifocal bone metastases in the absence of pulmonary spread. The metastatic lesions were of a similar histologic grade to the primary site. One of the patients had synchronous foci, while the other developed the bone lesions 3 years after initial presentation. The unusual behavior of these cases, as well as the possibility that they may represent instances of multicentric chondrosarcoma, is discussed.

Epithelioid hemangioma of bone. A tumor often mistaken for low-grade angiosarcoma or malignant hemangioendothelioma.

Epithelioid hemangiomas are benign vascular tumors that usually occur in the skin and subcutis. They have been infrequently recognized in bone. Because of their unusual cytologic appearance and growth patterns, they are commonly confused with malignant tumors. We report a series of 12 epithelioid hemangiomas of bone occurring in adult patients, including five males and seven females whose ages at presentation ranged from 24 to 74 years, with a mean of 46 years. Five tumors were associated with involvement of the adjacent soft tissue. A single patient had multifocal bone disease. The most common presenting symptom was localized pain. Treatment of the patients varied widely; however, none of the tumors behaved aggressively. In 11 cases, adequate tissue was available for immunohistochemical analysis, which revealed positive staining for the epithelial markers cytokeratin and epithelial membrane antigen in nine cases. All 11 tumors stained for factor VIII-related antigen and Ulex europeus agglutinin. We believe that many of the vascular tumors of bone that have been reported as low-grade malignant hemangioendotheliomas probably represent examples of epithelioid hemangiomas. We recommend that the criteria for diagnosing vascular tumors of bone conform to those used for morphologically similar tumors that arise in the soft tissues.

Meniscal tears of the knee: preliminary comparison of three-dimensional MR reconstruction with two-dimensional MR imaging and arthroscopy.

OBJECTIVE: A pilot study was performed to evaluate the usefulness of three-dimensional (3D) MR reconstructions in detecting meniscal tears. MATERIALS AND METHODS: Reconstructions of 24 knee menisci were made by using data from standard two-dimensional (2D) MR images. The results were compared with findings on 2D MR images and at arthroscopy. RESULTS: All 17 arthroscopically proved meniscal tears were shown on the 3D reconstructions. Seven tears in five patients were shown on 3D reconstruction but not on 2D MR images, even on retrospective examination. Three of the seven were radial tears and four were horizontal tears. The seven missed tears were all located in the posterior horns. CONCLUSION: Three-dimensional reconstructions are accurate for determining meniscal abnormalities and may be better than 2D imaging for evaluating the posterior horns of the menisci. Three-dimensional reconstructions may be indicated when 2D MR imaging shows no abnormality in patients in whom clinical findings strongly suggest a meniscal tear.

Limited remodelling of expansile Ewing sarcoma after treatment.

Radiological findings of Ewing sarcoma have been well documented, and bone expansion or cystic change is known to be a relatively uncommon finding. On the other hand, expected changes in Ewing sarcoma after treatment have also been reported, e.g. regression of extraosseous soft tissue mass, regression and organization of the periosteal reaction, and remodelling of the lytic or sclerotic bone changes. However, remodelling of bone is often limited or incomplete. We saw an atypical change in Ewing sarcoma after treatment due to lack of significant remodelling of the expanding bone. Because such changes might be a cause of misdiagnosis, knowledge of it will help the radiologist in the follow up evaluation.

Ossified soft tissue recurrence of giant cell tumor of bone.

We report 3 cases of soft tissue recurrence of giant cell tumor of bone. A peripheral rim of ossification in the soft tissue mass is pathognomonic of recurrence in the patients after resection of giant cell tumor.

Percutaneous needle biopsy of the spine.

The results of 75 percutaneous needle biopsies of the spine were analyzed. There were 8 cervical, 25 thoracic, 27 lumbar, and 15 sacral biopsies. An accurate diagnosis was made in 92% of all cases. Metastatic disease yielded the best accuracy rate (96%). The lowest accuracy rate (82%) was noted with benign primary tumors and fractures. The results were better in female patients than male (97% vs. 86%). Larger needles gave slightly better accuracy (97%). No relationship between accuracy and spine level was found. There were two complications: one pneumothorax and an episode of self-limited hemorrhage. Percutaneous needle biopsy is a safe and reliable method of obtaining a diagnosis in many different spine lesions.