Physeal and epiphyseal extent of primary malignant bone tumors in childhood. Correlation of preoperative MRI and the pathologic examination

Pediatric Osteosarcoma: Correlation of Imaging Findings with Histopathologic Features, Treatment, and Outcome

Osteosarcoma is the most common primary bone sarcoma in children. Imaging plays a pivotal role in diagnostic workup, surgical planning, and follow-up monitoring for possible disease relapse. Survival depends on multiple factors, including presence or absence of metastatic disease, chemotherapy response, and surgical margins. At diagnosis, radiography and anatomic MRI are used to characterize the primary site of disease, whereas chest CT and whole-body bone scintigraphy and/or PET are used to identify additional sites of disease. Treatment starts with neoadjuvant chemotherapy, followed by en bloc tumor resection and limb reconstruction, and finally, adjuvant chemotherapy. Preoperative planning requires precise tumor delineation, which traditionally has been based on high-spatial-resolution anatomic MRI to identify tumor margins (medullary and extraosseous), skip lesions, neurovascular involvement, and joint invasion. These findings direct the surgical approach and affect the options for reconstruction. For skeletally immature children, the risk of cumulative limb-length discrepancy and need for superior longevity of the reconstruction have led to the advent and preferential use of several pediatric-specific surgical techniques, including rotationplasty, joint preservation surgery, autograft or allograft reconstruction, and extendible endoprostheses. A better understanding of the clinically impactful imaging features can directly and positively influence patient care. Online supplemental material is available for this article. ^©RSNA, 2022.

A Reassessment of the Barrier Effect of the Physis against Metaphyseal Osteosarcoma: A Comprehensive Pathological Study with Its Radiological and Clinical Follow-Up Correlations

Osteosarcoma is a primary malignant bone tumor usually arising at the metaphysis of long bones, particularly around the knee. The physis has been regarded as a barrier capable of blocking tumor extension, thus allowing it to preserve their epiphysis and therefore improve functional results. With the objective of clarifying how effective the physis is as a barrier to tumor spread, a large series of skeletally immature patients with osteosarcoma were reviewed. From 452 metaphyseal osteosarcomas a selection of 282 cases in which the tumor was close or crossing the physis were carried out. This sub-sample was split into two groups according to the surgical treatment (epiphyseal preservation or not). The specimens obtained by resection were studied, and the physeal and metaphyseal areas were studied by multiple sections. Immunostaining against VEGF of physis was obtained in selected cases. In about half of the patients affected by metaphyseal malignant bone tumors, the growth plate and epiphysis were not compromised by the tumor. Three sequential invasive growth patterns of an osteosarcoma in its relationship with the physis could be distinguished. An intense angiogenesis and osteoclastic reaction could be observed in the growth plate in the free zone between the tumor and the physis. The local recurrence incidence was lower in the epiphyseal preservation treated patients than it was in the conventional treatment (8% vs. 12%). Most local recurrences appeared in the first 2 years. The overall survival of patients treated with epiphyseal preservation was better than that of the patients treated without preserving the epiphysis (73% vs. 59%; p = 0.03) at a mean follow-up of 18 years. We have described an angiogenic and osteoclastic reaction in the base of the growth plate in the proximity of the advance front of the tumor, which could facilitate the osteosarcoma invasion. It is also shown that the preoperative imaging method for examination is a valid approach for the decision to carry out epiphyseal preservation. Finally, we concluded that epiphyseal preservation combined with protective chemotherapy is an excellent clinical approach for selected patients with metaphyseal osteosarcoma.

Limited utility of intraoperative frozen sections in primary malignant tumours involving long bones - A multicenter analysis of 475 cases

Background

In the surgical removal of primary malignant tumours involving long bones, intraoperative frozen sections are used to ascertain the adequacy of tumour clearance. However, with the improved imaging modalities that provide better foreknowledge of the tumour extent, it is possible that the arduous task of performing frozen sections can be safely avoided. This would not only save procedural time but also reduce hospital costs. Presently, there are no clear guidelines regarding the modality required intraoperatively to assess tumour margins in these cases. Hence, in our retrospective multicentre analysis, we aimed at determining the usefulness of frozen sections in these cases.

Materials and methods

Our study is a 3-centre retrospective analysis of 475 cases (513 tumour margins) involving the surgical removal of primary malignancies of long bones. The preoperative Magnetic Resonance Imaging (MRI) and intraoperative assessment of the split specimen of the tumours were used to determine marginal clearance in all the cases in addition to frozen sections in 410 of the margins.

Results

Of the 410 frozen sections (centres 1 and 2), only one margin was reported positive and another reported indeterminate. All other margins were reported negative. In the first case, a 2 cm additional bone-cut was done whereas in the second, the procedure was proceeded based on the intraoperative agreement without re-cutting the margin. All these margins were negative in the final histopathology. In addition, in Centre 3, where frozen sections were not available, all the 103 cases had negative margins in the final histopathology.

Conclusion

In primary malignancies involving long bones, intraoperative decision making with the aid of MRI has been sufficiently accurate in identifying the required tumour margin without frozen sections. Hence, the added time and cost incurred by doing an additional procedure can be avoided in these cases.

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Currently, there are no guidelines on the optimal marginal thickness required for tumour clearance in long bone tumours.

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Our frozen section study analysed the correlation between frozen sections and final histopathology results.

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Only 1 positive frozen smear was seen which was negative in the histopathology showing limited utility of frozen sections.

Reconstruction with customized, 3D-printed prosthesis after resection of periacetabular Ewing's sarcoma in children using "triradiate cartilage-based" surgical strategy:a technical note

Background

Surgery for Ewing sarcoma involving acetabulum in children is challenging. Considering the intrinsic structure of immature pelvis, trans-acetabular osteotomy through triradiate cartilage might be applied. The study was to describe the surgical technique and function outcomes of trans-acetabular osteotomy through triradiate cartilage and reconstruction with customized, 3D-printed prosthesis.

Methods

Two children with periacetabular ES were admitted to our hospital. The pre-operative imaging showed the triradiate cartilage was not penetrated or wholly affected by tumor. After neoadjuvant chemotherapy, the tumor was excised by trans-acetabular osteotomy basing on “triradiate cartilage strategy” and the acetabulum was reconstructed with the customized, 3D-printed prosthesis. The prosthesis was designed in Mimics software basing on the images from CT, optimized by topology technique, and examined in FE model. After implantation, the oncological and functional outcomes were evaluated with radiography, CT, and MSTS score.

Results

The operation time and intra-operative blood loss in these two children were 3.5h, 2.5h and 300 ml, 600 ml, respectively. The postoperative specimen showed the tumor was en bloc removed with safe margin. In the latest follow-up (48 months and 24 months), both patients were free of disease and had satisfactory function according to MSTS score. The radiography indicated the prosthesis fit the defect well without loosening.

Conclusion

The customized, 3D-printed prosthesis could provide optimal reconstruction of pelvic ring and satisfactory hip function after trans-acetabular osteotomy in children.

The translational potential of this article

This study provides promising results of implantation of customized 3D printing prosthesis in children’s pelvic sarcoma, which may bring a new design method for orthopaedic implants.

Comparison of ferumoxytol- and gadolinium chelate-enhanced MRI for assessment of sarcomas in children and adolescents

OBJECTIVES

We compared the value of ferumoxytol (FMX)- and gadolinium (Gd)-enhanced MRI for assessment of sarcomas in paediatric/adolescent patients and hypothesised that tumour size and morphological features can be equally well assessed with both protocols.

METHODS

We conducted a retrospective study of paediatric/adolescent patients with newly diagnosed bone or soft tissue sarcomas and both pre-treatment FMX- and Gd-MRI scans, which were maximal 4 weeks apart. Both protocols included T1- and T2-weighted sequences. One reader assessed tumour volumes, signal-to-noise ratios (SNR) of the primary tumour and adjacent tissues and contrast-to-noise ratios (CNR) of FMX- and Gd-MRI scans. Additionally, four readers scored FMX- and Gd-MRI scans according to 15 diagnostic parameters, using a Likert scale. The results were pooled across readers and compared between FMX- and Gd-MRI scans. Statistical methods included multivariate analyses with different models.

RESULTS

Twenty-two patients met inclusion criteria (16 males, 6 females; mean age 15.3 ± 5.0). Tumour volume was not significantly different on T1-LAVA (p = 0.721), T1-SE (p = 0.290) and T2-FSE (p = 0.609) sequences. Compared to Gd-MRI, FMX-MRI demonstrated significantly lower tumour SNR on T1-LAVA (p < 0.001), equal tumour SNR on T1-SE (p = 0.104) and T2-FSE (p = 0.305), significantly higher tumour-to-marrow CNR (p < 0.001) on T2-FSE as well as significantly higher tumour-to-liver (p = 0.021) and tumour-to-vessel (p = 0.003) CNR on T1-LAVA images. Peritumoural and marrow oedema enhanced significantly more on Gd-MRI compared to FMX-MRI (p < 0.001/p = 0.002, respectively). Tumour thrombi and neurovascular bundle involvement were assessed with a significantly higher confidence on FMX-MRI (both p < 0.001).

CONCLUSIONS

FMX-MRI provides equal assessment of the extent of bone and soft tissue sarcomas compared to Gd-MRI with improved tumour delineation and improved evaluation of neurovascular involvement and tumour thrombi. Therefore, FMX-MRI is a possible alternative to Gd-MRI for tumour staging in paediatric/adolescent sarcoma patients.

KEY POINTS

• Ferumoxytol can be used as an alterative to gadolinium chelates for MRI staging ofpaediatric sarcomas. • Ferumoxytol-enhanced MRI provides equal assessment of tumour size and other diagnostic parameters compared to gadolinium chelate-enhanced MRI. • Ferumoxytol-enhanced MRI provides improved delineation of sarcomas from bone marrow, liver and vessels compared to gadolinium chelate-enhanced MRI.

Planning for Bone Excision in Ewing Sarcoma: Post-Chemotherapy MRI More Accurate Than Pre-Chemotherapy MRI Assessment

BACKGROUND

In determining the level of bone resection in Ewing sarcoma, the most suitable time at which to perform magnetic resonance imaging (MRI) remains controversial. Current guidelines recommend that surgical planning be based on MRI performed prior to neoadjuvant chemotherapy. The goal of this study was to determine whether pre-chemotherapy or post-chemotherapy MRI provides greater accuracy of tumor limits for planning bone excision in the management of Ewing sarcoma.

METHODS

This was a single-center, retrospective study. MRI was performed using 3 sequences: T1-weighted, T1-weighted with contrast enhancement by gadolinium injection, and a fluid-sensitive sequence (STIR [short tau inversion recovery] or proton-density-weighted with fat saturation). The tumor extent as assessed on pre-chemotherapy and post-chemotherapy MRI was compared with histological measurement of the resected specimen.

RESULTS

Twenty patients with Ewing sarcoma of a long bone were included. In 6 cases, the tumor was located on the femur, in 5, the tibia; in 5, the fibula; and in 4, the humerus. The median patient age at diagnosis was 9.7 years. We found greater accuracy of measurements from MRI scans acquired after chemotherapy than from those acquired before chemotherapy. For both pre-chemotherapy and post-chemotherapy MRI, the greatest accuracy was achieved with the nonenhanced T1 sequence. There was no benefit to gadolinium enhancement. The median difference between T1 MRI and histological measurements was 19.0 mm (interquartile range [IQR], 4.3 to 32.8 mm) before chemotherapy and 5.0 mm (IQR, 2.0 to 13.0 mm) after chemotherapy. Adding a minimum margin of 20 mm to the limit of the tumor on post-chemotherapy T1 MRI always led to safe histological margin.

CONCLUSIONS

Post-chemotherapy MRI provided a more accurate assessment of the limits of Ewing sarcoma. Surgical planning can therefore be based on post-chemotherapy MRI. Surgical cuts can be, at minimum, 20 mm from the limits as seen on MRI.

Surgical management of pelvic Ewing's sarcoma in children and adolescents

The present study describes a novel surgical strategy used to treat immature pelvic Ewing's sarcoma (ES), one made possible owing to the intrinsic structure of the skeletally immature pelvis. A total of 12 children and adolescents with open triradiate cartilage received limb-salvage surgeries following a diagnosis of pelvic ES. In total, 3 patients with iliac lesions (2 lesions with extension into the sacrum) received surgical tumor excisions and allograft reconstructions. Another 8 patients with periacetabular lesions received trans-acetabular osteotomies and allograft reconstructions. No reconstruction was performed on 1 patient following excision of a pubic lesion. The median follow-up time was 39 months. At the time of the final follow-up appointment, 9 patients exhibited no evidence of disease, 2 patients had slow progressive pulmonary metastasis, 1 patient exhibited local recurrence of the disease and 1 patient had succumbed to the disease 24 months after surgery. Complications included issues with wound healing in 1 patient, a discrepancy in leg length in another and a screw loosening in a further patient. The patients had a mean Musculoskeletal Tumor Society score of 26 points and a mean International Society of Limb Salvage radiographic score of 90.1%. The proposed surgical strategy for children and adolescents with pelvic ES in the present study could provide a feasible solution for acetabulum salvage and local tumor control.

Accuracy of Various MRI Sequences in Determining the Tumour Margin in Musculoskeletal Tumours

Background

It is imperative that bone tumour margin and extent of tumour involvement are accurately assessed pre-operatively in order for the surgeon to attain a safe surgical margin. In this study, we comprehensively assessed each of the findings that influence surgical planning, on various MRI sequences and compared them with the gold standard – pathology.

Material/Methods

In this prospective study including 21 patients with extremity bone tumours, margins as seen on various MRI sequences (T1, T2, STIR, DWI, post-gadolinium T1 FS) were measured and biopsies were obtained from each of these sites during the surgical resection. The resected tumour specimen and individual biopsy samples were studied to assess the true tumour margin. Margins on each of the MRI sequences were then compared with the gold standard – pathology. In addition to the intramedullary tumour margin, we also assessed the extent of soft tissue component, neurovascular bundle involvement, epiphyseal and joint involvement, and the presence or absence of skip lesions.

Results

T1-weighted imaging was the best sequence to measure tumour margin without resulting in clinically significant underestimation or overestimation of the tumour extent (mean difference of 0.8 mm; 95% confidence interval between −0.9 mm to 2.5 mm; inter-class correlation coefficient of 0.998). STIR and T1 FS post-gadolinium imaging grossly overestimated tumour extent by an average of 16.7 mm and 16.8 mm, respectively (P values <0.05). Post-gadolinium imaging was better to assess joint involvement while T1 and STIR were the best to assess epiphyseal involvement.

Conclusions

T1-weighted imaging was the best sequence to assess longitudinal intramedullary tumour extent. We suggest that osteotomy plane 1.5 cm beyond the T1 tumour margin is safe and also limits unwarranted surgical bone loss. However, this needs to be prospectively proven with a larger sample size.

Rapidly growing giant cell tumor of bone in a skeletally immature girl

Giant cell tumor of bone (GCTB) in skeletally immature patients is rare, and little is known regarding how fast GCTB can grow. We report a case of a 10-year-old skeletally immature girl with pathologically proven GCTB with obvious growth plate invasion that showed surprisingly rapid growth over only 14 days. A radiograph of the left knee revealed well-circumscribed, geographic bone destruction at the distal metaphysis of the femur with a focal cortical defect, suggesting a pathologic fracture. No abnormal mineralization or periosteal reaction was seen. A CT without contrast and an MRI demonstrated a homogeneous lesion with cortical disruption posteriorly and laterally with a slight soft tissue extension. Biopsy showed numerous multinucleated giant cells and spindle-shaped mononuclear cells without any sign of malignancy, suggesting GCTB. However, rapid lesion enlargement and destruction of the surrounding cortex were noted 14 days after biopsy. Considering the amount of bone destruction, traditional treatment of curettage and bone cement would not suffice to sustain structural strength. In addition, considering the patient's age, the tumor location, and the aggressive course, a malignant tumor, especially a giant cell-rich osteosarcoma, could not be excluded. Therefore, en bloc resection, including the growth plate and prosthetic replacement, were performed. Confirmation of GCTB was made from a pathologic evaluation, and a breach to the growth plate was identified. Since very little inflammatory reaction, degenerative change, or aneurysmal, bone, cyst-like change was found, the growth plate invasion was confirmed as due to GCTB extension, not due to the preoperative biopsy.

Unusual Presentations of Focal Periphyseal Edema Zones: A Report of Bilateral Symmetric Presentation and Partial Physeal Closure

Focal periphyseal edema (FOPE) zones are areas of periphyseal edema seen near the time of physeal closure which are believed to be a physiologic phenomenon related to changes in distribution of forces around the physis as it closes. Since the original case series describing these areas of periphyseal edema, there has been little published in regard to FOPE zone outside of review articles. We present a set of three patients identified with focal periphyseal edema zones around the knee and compare our findings with the initial case series. We include a patient presenting with bilateral, nearly symmetric, focal periphyseal edema zones of the proximal tibia physis and a patient with partial closure of the physis at time of presentation, which were not reported in the original case series.

Ewing sarcoma of the tibia mimicking fibrous dysplasia

Ewing sarcoma (ES) family of tumors is the second most common primary bone malignancy in children. It usually presents as an aggressive looking lesion often located in the meta-diaphyseal region of long bones, with bone destruction, permeation, cortical thinning and/or destruction, periosteal reaction, and large soft-tissue mass. The purpose of this study is to illustrate the occurrence of a fibrous dysplasia (FD)-appearing ES of the tibia. These cases underscore the potential difficulties encountered in the diagnosis of ES. In this study, we performed a retrospective review of children who presented with an otherwise benign-appearing lesion of the tibia, suggestive of FD, which proved to be ES after biopsy. As a result, all patients presented with a history of indolent lower extremity pain of several months of duration, without significant swelling or constitutional symptoms. Plain films revealed an otherwise benign-appearing/FD-like lesion without bone destruction and mild cortical thinning, little or no periosteal reaction. Magnetic resonance imaging revealed the intramedullary extension of the lesion without significant cortical or periosteal involvement and no soft tissue mass. Lesions were hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging. All patients underwent open incisional biopsy and after cytogenetic and molecular studies, the diagnosis of ES was confirmed. We conclude that ES is a deadly malignant tumor if left untreated or if mismanaged. Although it usually presents as an aggressive-looking lesion, at times it may mimic FD and has a benign-looking appearance, making the diagnosis unlikely and challenging. Summation of these cases demonstrates that the potential reasons for misdiagnoses include a low level of suspicion, an atypical site occurrence, a benign radiographic appearance, and a lack of or insufficient histologic specimens.

Ewing's sarcoma/primitive neuroectodermal tumor of the proximal humeral epiphysis

Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) of bone is a rare childhood tumor most commonly located in the metadiaphysis. In skeletally immature patients, lesions of the epiphysis are rarely malignant, with the most common diagnosis being chondroblastoma. This article presents a case of ES/PNET of the proximal humeral epiphysis in a 12-year-old boy. To the authors' knowledge, this is the first reported case of epiphyseal ES/PNET confirmed with molecular testing. Radiographs of the patient's painful shoulder showed a well-defined lytic lesion within the humeral epiphysis. Magnetic resonance imaging suggested a chondroid tumor with surrounding edema. Based on the imaging characteristics, the patient's age, and the lesion's location, a preliminary diagnosis of chondroblastoma was made. A trochar biopsy of the lesion demonstrated a small, round, blue cell tumor on frozen section. Subsequently, immunohistochemical staining was uniformly positive in a membrane pattern for CD99, and molecular diagnostic testing demonstrated a EWSR1/FLI1 fusion transcript, confirming the pathologic diagnosis of ES/PNET. Although metadiaphyseal locations for ES/PNET are most common, this case adds to previously reported cases of epiphyseal ES/PNET, suggesting that the diagnosis be considered for pediatric epiphyseal tumors. This case also demonstrates why following rigorous oncologic treatment algorithms by obtaining a limited trochar biopsy, even in the case of a confident radiographic diagnosis, is critically important; the biopsy results can lead to a major change in treatment and avoid contamination of a larger area of soft tissue and bone.

Correlation of non-mass-like abnormal MR signal intensity with pathological findings surrounding pediatric osteosarcoma and Ewing's sarcoma

OBJECTIVE

The aim of this work was to determine the role of MRI in interpreting abnormal signals within bones and soft tissues adjacent to tumor bulk of osteosarcoma and Ewing's sarcoma in a pediatric population by correlating MR findings with histopathology.

MATERIALS AND METHODS

Thirty patients met the inclusion criteria, which included (1) osteosarcoma or Ewing's sarcoma, (2) MR studies no more than 2 months prior to surgery, (3) presence of abnormal MR signal surrounding the tumor bulk, (4) pathological material from resected tumor. The patients received standard neoadjuvant chemotherapy. Using grid maps on gross pathology specimens, the abnormal MR areas around the tumor were matched with the corresponding grid sections. Histopathology slides of these sections were then analyzed to determine the nature of the regions of interest. The MR/pathological correlation was evaluated using Mann-Whitney U test and Fisher's exact test.

RESULTS

Twenty-seven patients had osteosarcoma and three patients had Ewing's sarcoma. Of the studied areas, 17.4% were positive for tumor (viable or necrotic). There was no statistically significant correlation between areas positive for tumor and age, gender, signal extent and intensity on MRI, or tissue type. There was, however, a statistically significant correlation between presence of tumor and the appearance of abnormal soft tissue signals. A feathery appearance correlated with tumor-negative areas whereas a bulky appearance correlated with tumor-positive regions.

CONCLUSIONS

MR imaging is helpful in identifying the nature of abnormal signal areas surrounding bone sarcomas that are more likely to be tumor-free, particularly when the signal in the soft tissues surrounding the tumor is feathery and edema-like in appearance.

18F-FDG PET/CT compared to conventional imaging modalities in pediatric primary bone tumors

BACKGROUND

F-Fluoro-2-deoxy-D: -glucose (FDG) positron emission tomography (PET) is useful in adults with primary bone tumors. Limited published data exist in children.

OBJECTIVE

To compare hybrid FDG positron emission tomography/computed tomography (PET/CT) with conventional imaging (CI) modalities in detecting malignant lesions, predicting response to chemotherapy and diagnosing physeal involvement in pediatric primary bone tumors.

MATERIALS AND METHODS

Retrospective analysis of PET/CT and CI reports with histopathology or follow-up > 6 months as reference standard. Response parameters and physeal involvement at diagnosis were compared to histopathology.

RESULTS

A total of 314 lesions were detected in 86 scans. Excluding lung lesions, PET/CT had higher sensitivity and specificity than CI (83%, 98% and 78%, 97%, respectively). In lung lesions, PET/CT had higher specificity than CI (96% compared to 87%) but lower sensitivity (80% compared to 93%). Higher initial SUV(max) and greater SUV(max) reduction on PET/CT after chemotherapy predicted a good response. Change in tumor size on MRI did not predict response. Both PET/CT and MRI were very sensitive but of low specificity in predicting physeal tumor involvement.

CONCLUSION

PET/CT appears more accurate than CI in detecting malignant lesions in childhood primary bone tumors, excluding lung lesions. It seems better than MRI at predicting tumor response to chemotherapy.

Analysis of limb function after various reconstruction methods according to tumor location following resection of pediatric malignant bone tumors

Background

In the reconstruction of the affected limb in pediatric malignant bone tumors, since the loss of joint function affects limb-length discrepancy expected in the future, reconstruction methods that not only maximally preserve the joint function but also maintain good limb function are necessary. We analysis limb function of reconstruction methods by tumor location following resection of pediatric malignant bone tumors.

Patients and methods

We classified the tumors according to their location into 3 types by preoperative MRI, and evaluated reconstruction methods after wide resection, paying attention to whether the joint function could be preserved. The mean age of the patients was 10.6 years, Osteosarcoma was observed in 26 patients, Ewing's sarcoma in 3, and PNET(primitive neuroectodermal tumor) and chondrosarcoma (grade 1) in 1 each.

Results

Type I were those located in the diaphysis, and reconstruction was performed using a vascularized fibular graft(vascularized fibular graft). Type 2 were those located in contact with the epiphyseal line or within 1 cm from this line, and VFG was performed in 1, and distraction osteogenesis in 1. Type III were those extending from the diaphysis to the epiphysis beyond the epiphyseal line, and a Growing Kotz was mainly used in 10 patients. The mean functional assessment score was the highest for Type I (96%: n = 4) according to the type and for VFG (99%) according to the reconstruction method.

Conclusion

The final functional results were the most satisfactory for Types I and II according to tumor location. Biological reconstruction such as VFG and distraction osteogenesis without a prosthesis are so high score in the MSTS rating system. Therefore, considering the function of the affected limb, a limb reconstruction method allowing the maximal preservation of joint function should be selected after careful evaluation of the effects of chemotherapy and the location of the tumor.

Avaliação por imagem das lesões da placa de crescimento

As estruturas responsáveis pelo crescimento do osso incluem a fise (também chamada placa de crescimento) e as epífises. Afecções que acometem pacientes com o esqueleto imaturo, ou seja, com a placa de crescimento ainda aberta, podem interferir no crescimento ósseo, resultando em complicações como parada do crescimento, encurtamento dos membros ou deformidades angulares. Condições traumáticas que resultam muitas vezes em fraturas epifisárias são a causa mais comum das lesões da placa de crescimento. A avaliação cuidadosa desses pacientes pelos métodos de diagnóstico por imagem atualmente disponíveis, sobretudo a radiografia, a tomografia computadorizada e a ressonância magnética, permite o reconhecimento precoce do comprometimento das estruturas relacionadas ao crescimento ósseo, além de tratamento adequado, diminuindo a possibilidade do desenvolvimento de tais complicações.

Radiological appearances of appendicular osteosarcoma: a comprehensive pictorial review

Osteosarcoma is the most common primary malignant tumour of bone in adolescents and young adults. Hence, a comprehensive knowledge of the common and unusual imaging appearance of this tumour is essential. Correct diagnosis of the various varieties of osteosarcoma is important for optimal clinical management including staging, biopsy, treatment and follow-up of patients. This review article provides a comprehensive approach to the radiological diagnosis of the different types of appendicular osteosarcoma and illustrates the role of CT and MRI in further characterisation.

Imaging of malignant tumours of the long bones in children: monitoring response to neoadjuvant chemotherapy and preoperative assessment

This review focuses on imaging of osteosarcoma and Ewing's sarcoma of the long bones in children during preoperative neoadjuvant chemotherapy. Morphological criteria on plain films and conventional static MRI are insufficiently correlated with histological response. We review the contribution of dynamic MRI, diffusion-weighted MR and nuclear medicine (18FDG-PET) to monitor tumoural necrosis. MRI is currently the best method to evaluate local extension prior to tumour resection, especially to assess the feasibility of conservative surgery. Quantitative models in dynamic MRI and 18FDG-PET are currently being developed in order to find new early prognostic criteria, but for the time being, treatment protocols are still based on the gold standard of histological response.

Malignant bone tumors and limb-salvage surgery in children

Limb-salvage surgery plays a major role in the management of children with malignant bone tumors. This article provides background on the clinical presentation and imaging evaluation of children with malignant bone tumors and describes various limb-salvage procedures used in the treatment of these children.

The role of imaging in the staging and treatment planning of primary malignant bone tumors in children

The accurate staging of primary bone tumors in children is critical for treatment planning. Limb salvage operations can now be performed with excellent outcomes in suitable patients. The purpose of this article is to review the current state of imaging techniques and their roles in enabling accurate staging and treatment planning to be performed in pediatric patients with primary bone tumors.

Accuracy of magnetic resonance imaging for estimating intramedullary osteosarcoma extent in pre-operative planning of canine limb-salvage procedures

The objective of this work was to compare the accuracy of radiographs and magnetic resonance imaging (MRI) for estimating appendicular osteosarcoma margins. The accuracy of computed tomography (CT) and bone scintigraphy was also assessed when these studies were available. Eight dogs with appendicular osteosarcoma underwent radiographic and MRI of affected limbs. In addition, bone scintigraphy was performed in six dogs and CT examination was performed in five dogs. Two observers jointly measured tumor length on all imaging studies. Correlative gross and histologic evaluation of all affected limbs was performed to determine tumor extent as measured from the nearest articular surface. Results from imaging studies were compared to gross and microscopic morphometry findings to determine the accuracy of each modality for determining tumor boundaries. MRI images were accurate with a mean overestimation of actual tumor length of 3 +/- 13%. T1-weighted non-contrast images were superior in identifying intramedullary tumor margins in most instances whereas contrast-enhanced images provided supplemental information in two dogs. Lateromedial and craniocaudal radiographs overestimated tumor length by 17 +/- 28% and 4 +/- 26%, respectively. Scintigraphy and CT overestimated tumor margins by 14 +/- 28% and 27 +/- 36%, respectively. MRI appears to be an accurate diagnostic imaging modality in determining intramedullary osteosarcoma boundaries. MRI should be considered as part of a pre-operative assessment of appendicular osteosarcoma, particularly when a limb-sparing procedure is contemplated.

Growth plate chondrocytes inhibit neo-angiogenesis -- a possible mechanism for tumor control

Clinically, tumors seldom grow across the articular cartilage and physeal plate. It is believed that avascular cartilage may inhibit the neo-vascularization of tumor spread. The conditioned medium of growth plate chondrocytes resisted the migration of ECV304 by approximately 41% in invasion assay. Growth plate chondrocytes were shown by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to have an insignificant effect on the viability of human endothelial cells and fibroblasts. However, the proliferation of human endothelial cells was significantly inhibited by growth plate chondrocytes. The inhibitory activity was up to 35% and specific to endothelial cells. Inhibition of blood vessel formation was also demonstrated in the chick chorioallantoic membrane (CAM) assay. These findings demonstrated that growth plate chondrocytes secrete anti-angiogenesis factor(s) which specifically inhibit both the migration and proliferation of endothelial cells.

MRI of primary lymphoma of bone: cortical disorder as a criterion for differential diagnosis

To investigate the pattern and dimension of cortical bone abnormality on magnetic resonance imaging (MRI) as a feature to distinguish primary lymphoma of bone from osteosarcoma and Ewing sarcoma, 46 patients with primary malignant bone lesions with a soft tissue mass (16 osteosarcomas, 15 Ewing sarcomas, 15 lymphomas) were examined with MRI (T1-weighted pre-/postcontrast spin-echo sequences and T2-weighted spin-echo and fast spin-echo sequences; 1.5 T system). Qualitative image analysis revealed no differences for signal characteristics and enhancement. Lymphomas appeared significantly more often homogeneous (47%; Ewing sarcoma 20%; osteosarcoma 6%/o), and patients were significantly older (cutoff point 30 years). Lymphomas showed significantly less frequent cortical abnormality (60%; Ewing sarcoma 87%; osteosarcoma 100%), complete penetration (13%; Ewing sarcoma 67%; osteosarcoma 87%), focal destruction (13%; Ewing sarcoma 40%; osteosarcoma 81%), and complete destruction (0%; Ewing sarcoma 13%; osteosarcoma 19%). In conclusion, primary lymphoma of bone is characterized by minimal cortical changes despite an accompanying soft tissue mass in a patient over 30 years of age.

Imaging the child with a limp

A great many pathologic conditions can cause a child to limp. Prior to imaging, it is necessary to complete a thorough history and physical examination in order to limit the differential diagnosis to a few possible causes. The selection of imaging modalities should then be guided by the history and physical examination findings. Because of their sensitivity and specificity for detecting a wide range of bone pathology, radiographs should be obtained first. Plain radiographs often are diagnostic. The choice of sonography, CT, bone scintigraphy, or MR imaging is made while keeping in mind the strengths of each imaging modality.