Relevance of MRI in prediction of malignancy of musculoskeletal system--a prospective evaluation

Management of Ewing Sarcoma of Distal Fibula in Child: A Case Report

Introduction

Ewing's sarcoma is the second most common primary malignant bone tumor in children and adolescents, after osteosarcoma. It is a rare tumor, with the axial skeleton being the preferred site of development, followed by the long bones. Diagnosis is evoked by imaging and confirmed by histology. Treatment is based on intensive chemotherapy with local surgical treatment in operable forms, and in some cases, radiotherapy. There are only a few sporadic cases in the literature describing distal fibular localization.

Case Report

We report the case of a 7-year-old child who presented with pain on the lateral aspect of the left ankle without local inflammatory signs. Radiological findings revealed a metaphyseal-diaphyseal osteolytic tissue process of the left fibula, and histology concluded that it was Ewing's sarcoma. We proceeded with neoadjuvant polychemotherapy followed by segmental resection of the distal fibula with an anteroexternal tibial rod, plus tibiotalar, and talocalcaneal arthrodesis without recourse to radiotherapy.

Conclusion

The management of Ewing's sarcoma is constantly evolving. Its distal fibular location in a growing limb makes it even more difficult. It must be personalized, multidisciplinary, and carried out in specialized centers.

Adherence and Satisfaction With Intensive Physiotherapy Treatment During Ongoing Chemotherapy Sessions in Patients With Chest Wall Ewing Sarcoma

Ewing sarcoma (ES) is a highly fatal bone and soft tissue cancer that predominantly impacts adolescents and children. Primary ES can occasionally manifest as a tumour on the chest wall. Treatment typically consists of radiation, local surgery, and polychemotherapy, all of which have acute and chronic side effects that can detrimentally affect survivors' quality of life (QOL). In this case study, we discussed the case of a 19-year-old female who came with chief complaints of chest pain, swelling on the right side of her neck, difficulty breathing, and pain in her right shoulder radiating to her right arm and forearm for one year. She was diagnosed with ES of the chest wall and underwent chemotherapy treatment for the same at our tertiary care hospital. Our aim was to find out the role of physiotherapy, considering the radiological, pathological, and clinical aspects of the disease while the patient is undergoing chemotherapy sessions, which has been highlighted and found to be effective in increasing satisfaction levels, adherence to the treatment, improving muscle strength, lung function, and overall QOL.

Evaluation of Potential Targets for Fluorescence-Guided Surgery in Pediatric Ewing Sarcoma: A Preclinical Proof-of-Concept Study

Fluorescence-guided surgery (FGS), based on fluorescent tracers binding to tumor-specific biomarkers, could assist surgeons to achieve complete tumor resections. This study evaluated potential biomarkers for FGS in pediatric Ewing sarcoma (ES). Immunohistochemistry (IHC) was performed to assess CD99, CXCR4, CD117, NPY-R-Y1, and IGF-1R expression in ES biopsies and resection specimens. LINGO-1 and GD2 evaluation did not work on the acquired tissue. Based on the immunoreactive scores, anti-CD99 and anti-CD117 were evaluated for binding specificity using flow cytometry and immunofluorescence microscopy. Anti-GD2, a tracer in the developmental phase, was also tested. These three tracers were topically applied to a freshly resected ES tumor and adjacent healthy tissue. IHC demonstrated moderate/strong CD99 and CD117 expression in ES tumor samples, while adjacent healthy tissue had limited expression. Flow cytometry and immunofluorescence microscopy confirmed high CD99 expression, along with low/moderate CD117 and low GD2 expression, in ES cell lines. Topical anti-CD99 and anti-GD2 application on ES tumor showed fluorescence, while anti-CD117 did not show fluorescence for this patient. In conclusion, CD99-targeting tracers hold promise for FGS of ES. CD117 and GD2 tracers could be potential alternatives. The next step towards development of ES-specific FGS tracers could be ex vivo topical application experiments on a large cohort of ES patients.

Magnetic resonance imaging in differentiating between aggressive and non-aggressive bone tumors

BACKGROUND

While radiography remains essential in the initial evaluation of bone lesions, tissue biopsy or further imaging is often required to clarify indeterminate radiographic features. Magnetic resonance imaging (MRI) assists radiologists in evaluating lesions with indeterminate features as it has advantages in delineating tumorous tissues and bone marrow.

PURPOSE

To evaluate the association factors of MRI for bony aggressiveness.

MATERIAL AND METHODS

A retrospective analysis of 226 MRI examinations from patients diagnosed with bone tumors in a tertiary hospital during 2008-2018 was performed. All the MR images were interpreted by musculoskeletal radiologists without diagnostic information. The bony lesions were categorized into aggressive and non-aggressive groups using tumor margin, cortical changes, periosteal reaction, joint extension, extraosseous soft tissue involvement, tumor homogeneity, and enhancement pattern from the MR images. Univariable and multivariable analysis were applied for each feature on the MRI scans. In addition, sensitivity and specificity were calculated for MRI diagnoses of aggressive bone lesions.

RESULTS

In total, 180 aggressive and 46 non-aggressive bone lesions were examined on MRI. The sensitivity and specificity of MRI for differentiating between aggressive and non-aggressive bone lesions were 98.89% and 50%, respectively. Ill-defined margin, cortical break, cortical signal changes, sunburst and Codman's triangle periosteal reaction, joint extension, and tumoral and heterogeneous enhancement could be predictive signs for aggressive bone lesions.

CONCLUSION

MRI can be a valuable tool to assist in distinguishing aggressive from non-aggressive bone lesions. In cases of indeterminate radiographic features, MRI could be used as an additional imaging to improve diagnostic accuracy and could reduce unnecessary invasive procedures.

"Do-not-touch" lesions of bone revisited

Incidental bone lesions are encountered frequently in day-to-day practice. Many of these lesions are indeterminate requiring referral to specialist centres for further characterisation with or without biopsy; however, as biopsy has its own drawbacks, not all lesions can be subjected to biopsy. The primary role of a radiologist in these situations is to characterise these lesions based on their imaging appearances into aggressive lesions requiring biopsy and non-aggressive lesions that do not require a biopsy. The term "do-not-touch lesion" is used to describe a lesion with typical radiographic appearances that can be characterised based on radiographic appearances alone without needing a biopsy. With recent advances in imaging, many incidental lesions can be characterised into do-not-touch lesions based on their imaging appearances alone using a single imaging technique or using a combination of imaging techniques and, less frequently, with the additional help of serological investigations, without the need for biopsy. Hence, the definition of do-not-touch lesions of bone needs a revisit. In this article, we attempt to redefine do-not-touch lesions of bone and propose an imaging-based classification for characterisation of these lesions.

Ewing Sarcoma-Diagnosis, Treatment, Clinical Challenges and Future Perspectives

Ewing sarcoma, a highly aggressive bone and soft-tissue cancer, is considered a prime example of the paradigms of a translocation-positive sarcoma: a genetically rather simple disease with a specific and neomorphic-potential therapeutic target, whose oncogenic role was irrefutably defined decades ago. This is a disease that by definition has micrometastatic disease at diagnosis and a dismal prognosis for patients with macrometastatic or recurrent disease. International collaborations have defined the current standard of care in prospective studies, delivering multiple cycles of systemic therapy combined with local treatment; both are associated with significant morbidity that may result in strong psychological and physical burden for survivors. Nevertheless, the combination of non-directed chemotherapeutics and ever-evolving local modalities nowadays achieve a realistic chance of cure for the majority of patients with Ewing sarcoma. In this review, we focus on the current standard of diagnosis and treatment while attempting to answer some of the most pressing questions in clinical practice. In addition, this review provides scientific answers to clinical phenomena and occasionally defines the resulting translational studies needed to overcome the hurdle of treatment-associated morbidities and, most importantly, non-survival.

Added Value of Diffusion-Weighted Magnetic Resonance Imaging in Differentiating Musculoskeletal Tumors Using Sensitivity and Specificity: A Retrospective Study and Review of Literature

Background: Diffusion-weighted imaging (DWI) provides added value to conventional MRI imaging in diagnosing and differentiating various benign and malignant musculoskeletal tumors.

Objective: The study aims to evaluate the diagnostic efficacies of diffusion-weighted imaging along with the conventional MRI sequences for differentiating benign and malignant musculoskeletal tumors using sensitivity and specificity.

Materials and methods: This retrospective study was carried out on 73 histopathologically proven patients of various musculoskeletal tumors who presented to a tertiary care center between March 2017 to October 2018. Relevant clinical examinations and MRI scan of the requested body part of the musculoskeletal system were performed. Mean apparent diffusion coefficient (ADC) values were calculated in the bone as well as soft tissue tumors after placing uniform-sized region of interest (ROI) in the non-necrotic portion of the tumor.

Statistical analysis: Independent t-test and one-way analysis of variance (ANOVA) test were used to compare the mean ADC values of the various tumors with the histopathology. Receiver operating characteristic (ROC) curve analysis was done to determine the cut-off mean ADC values in the various bone and soft tissue tumors.

Results: Of 73 patients with musculoskeletal tumors (benign=20, malignant = 53), 47 patients were bone tumors (benign=12, malignant=35) and 26 patients were soft tissue tumors (benign=eight, malignant=18). Mean ADC value of benign bone tumor was 1.257±0.327[SD] x 10^-3mm2/s and malignant was 0.951 ± 0.177[SD] x 10^-3mm2/s. The mean ADC value of benign soft tissue tumor was 1.603±0.444[SD] x 10^-3mm2/s and malignant was 1.036 ± 0.186[SD] x 10^-3mm2/s. The cut-off mean ADC value was 1.058 x 10^-3mm2/s for differentiating benign from malignant bone tumor with a sensitivity of 83.3%, specificity of 66.7% and accuracy of 78.7% while the cut-off mean ADC value of 1.198 x 10^-3mm2/s for differentiating benign from malignant soft tissue tumors with a sensitivity of 83.3%, specificity of 87.5% and accuracy of 84.6%.

Conclusions: DWI with ADC mapping can be used as an additional reliable tool along with conventional MRI sequences in discriminating benign and malignant musculoskeletal tumors.

Imaging of rare appendicular non-acral soft-tissue chondromas in adults with histopathologic correlation

Background Soft-tissue chondroma (STC) is a rare benign soft tissue tumor that arises primarily in acral extra-skeletal locations. Occasionally, STCs may arise in more proximal non-acral locations, accompanied by non-classic features that label them as indeterminate lesions and pose diagnostic challenge for both radiologists and pathologists alike. Purpose To explicate the potential of diagnostic imaging in the identification and characterization of appendicular non-acral STCs with emphasis on their morphologic magnetic resonance imaging (MRI) enhancement. Material and Methods Our clinical database records were searched for patients with histologically proven primary soft-tissue chondroid lesions over a five-year period. Two musculoskeletal (MSK) trained radiologists evaluated the imaging studies and an MSK pathologist revised the pathological findings. Results The study included six cases of appendicular non-acral STCs (mean age = 40.5 years). The mean size of the tumors was 5.6 cm, with four localized to the knee region, one in the thigh, and one in the sternoclavicular region. All cases showed high signal intensity matrix with low-signal intensity septa on T2-weighted MRI and post-contrast marginal/septal enhancement. The lesions were lobulated and lacked host tissue reaction except for one showing subjacent mild soft-tissue edema. Histologically, the cases lacked overt features of malignancy although one was originally misdiagnosed as chondrosarcoma. Conclusion Non-acral STCs are benign cartilaginous tumors that may pose a diagnostic challenge, both radiologically and pathologically. Collaborative imaging and pathologic workup is needed for better characterization of non-aggression of these lesions, and to avoid diagnostic pitfalls and unnecessary radical resections.

Diagnostic value of combined diffusion-weighted imaging with dynamic contrast enhancement MRI in differentiating malignant from benign bone lesions

AIM

To determine the diagnostic value of combined diffusion-weighted imaging (DWI) with dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) in differentiating malignant from benign bone lesions.

MATERIALS AND METHODS

DWI and DCE-MRI were performed in 36 patients (14 were benign and 22 were malignant). The mean apparent diffusion coefficient (ADC) values and signal enhanced extent (SEE), slope value, and time-signal intensity curve (TIC) type were recorded by two observers. Between-group comparison was made using the independent sample t-test and receiver-operating characteristic (ROC) analysis.

RESULTS

There was a significant difference between the mean ADC value of the benign ([1.75±0.50]×10^-3 mm²/s) and malignant ([1.11±0.47]×10^-3 mm²/s) groups (p=0.001). The threshold ADC value of ≤1.10×10^-3 mm²/s resulted in a sensitivity of 77.3%, a specificity of 92.9%, and an accuracy of 85.1%. A type III curve was found in 23 cases (21 malignant and two benign), a type II curve was seen in six cases (one malignant and five benign), and a type I curve in seven cases (all were benign). The SEE and slope values in the benign and malignant groups were 227.96±172.08, 325.60±125.86 (p=0.058); 0.97±0.67%/s, 3.19±3.20%/s (p=0.016), respectively. ROC analysis showed a sensitivity of 95.5%, a specificity of 85.7%, and an accuracy of 90.6% for malignancy, based on a slope cut-off value of >1.46%/s. Combining ADC and slope values resulted in a sensitivity of 100%, a specificity of 85.7%, and an accuracy of 92.9%.

CONCLUSIONS

Both DWI and DCE-MRI showed promising results for differentiating malignant from benign bone lesions. A combination of DWI and DCE-MRI was the most valuable of the three.

Characterisation of musculoskeletal tumours by multivoxel proton MR spectroscopy

OBJECTIVE

The purpose of this study is to evaluate the role of multi-voxel proton MR spectroscopy in differentiating benign and malignant musculoskeletal tumours in a more objective way and to correlate the MRS data parameters with histopathology.

METHODS AND MATERIALS

A hospital-based prospective study was carried out comprising 42 patients who underwent MRI examinations from 1 July 2013 to 30 June 2014. After routine sequences, single-slice multi-voxel proton MR spectroscopy was included at TE-135 using the PRESS sequence. The voxel with the maximum choline/Cr ratio was used for analysis of data in 32 patients. The strength of association between the MR spectroscopy findings and the nature of tumour and histopathological grading were assessed.

RESULTS

Of the 42 patients, the MR spectra were not of diagnostic quality in 10. In the remaining 32 patients, 12 (37.5%) had benign and 20 (62.5%) malignant tumours. The mean choline/Cr ratio was 6.97 ± 5.95 (SD) for benign tumours and 25.39 ± 17.72 (SD) for malignant tumours. In our study statistical significance was noted between the choline/Cr ratio and the histological nature of musculoskeletal tumours (p = 0.002) assessed by unpaired t-test. The choline/Cr ratio and histological grading were also found to be significant (p = 0.001) when assessed by one-way ANOVA test.

CONCLUSIONS

Multi-voxel MR spectroscopy showed a higher choline/Cr ratio in malignant musculoskeletal tumours than in benign ones (p = 0.002). The choline/Cr ratio and histological grading of musculoskeletal tumours also showed statistical significance (p = 0.001).

Soft-Tissue Tumor Contrast Enhancement Patterns: Diagnostic Value and Comparison Between Ultrasound and MRI

OBJECTIVE

The purpose of this study was to assess and compare contrast-enhanced ultrasound and MRI patterns in the diagnosis of soft-tissue masses.

MATERIALS AND METHODS

Two hundred fifty-five consecutively registered patients with histologically confirmed soft-tissue masses were included in this retrospective study. The diagnostic properties of four predefined contrast enhancement (CE) patterns were assessed, and logistic regression analysis was performed to determine the correlation between diagnosis and CE pattern, lesion size, and patient age and sex. The influence of lesion size on the occurrence of inhomogeneous CE patterns in malignancies was also determined.

RESULTS

Homogeneous CE patterns were highly specific for benignity, and inhomogeneous CE was moderately specific for malignancy in both ultrasound and MRI. A combination of homogeneous and inhomogeneous CE patterns led to 88.3% and 88.7% sensitivity, 66.7% and 59.7% specificity, 73.4% and 68.2% correct classification, 54.6% and 47.8% positive predictive value, 92.6% and 92.7% negative predictive value, 2.65 and 2.20 positive likelihood ratio, and 0.18 and 0.19 negative likelihood ratio for contrast-enhanced ultrasound and contrast-enhanced MRI. Cases with homogeneous CE in either ultrasound or MRI also were predominantly benign. The occurrence of inhomogeneous CE in malignant lesions increased with size.

CONCLUSION

CE patterns in ultrasound and MRI offer additional information about the differentiation of an unknown soft-tissue mass. The results of this study showed that homogeneous or absent CE was specific for benign differentiation and that heterogeneous CE was linked to malignancy. The routine analysis of CE patterns should increase diagnostic reliability in unclear soft-tissue masses.

Intra-Articular Synovial Sarcomas: Incidence and Differentiating Features from Localized Pigmented Villonodular Synovitis

Purpose. To determine the incidence of intra-articular synovial sarcomas and investigate if any radiological variables can differentiate them from localized (unifocal) pigmented villonodular synovitis (PVNS) and if multivariate data analysis could be used as a complementary clinical tool. Methods. Magnetic resonance images and radiographs of 7 cases of intra-articular synovial sarcomas and 14 cases of localized PVNS were blindedly reviewed. Variables analyzed were size, extra-articular growth, tumor border, blooming, calcification, contrast media enhancement, effusion, bowl of grapes sign, triple signal intensity sign, synovial low signal intensity, synovitis, age, and gender. Univariate and multivariate data analysis, the method of partial least squares-discriminant analysis (PLS-DA), were used. Register data on all synovial sarcomas were extracted for comparison. Results. The incidence of intra-articular synovial sarcomas was 3%. PLS-DA showed that age, effusion, size, and gender were the most important factors for discrimination between sarcomas and localized PVNS. No sarcomas were misclassified as PVNS with PLS-DA, while some PVNS were misclassified as sarcomas. Conclusions. The most important variables in differentiating intra-articular sarcomas from localized PVNS were age, effusion, size, and gender. Multivariate data analysis can be helpful as additive information to avoid a biopsy, if the tumor is classified as most likely being PVNS.

Accuracy and role of contrast-enhanced CT in diagnosis and surgical planning in 88 soft tissue tumours of extremities

OBJECTIVES

Soft tissue tumours (STT) require accurate diagnosis in order to identify potential malignancies. Preoperative planning is fundamental to avoid inadequate treatments. The role of contrast-enhanced computed tomography (CT) for local staging remains incompletely assessed. Aims of the study were to evaluate CT accuracy in discriminating active from aggressive tumours compared to histology and evaluate the role of CT angiography (CTA) in surgical planning.

MATERIALS AND METHODS

This retrospective cohort series of 88 cases from 1200 patients (7 %) was locally studied by contrast-enhanced CT and CTA in a referral centre: 74 malignant tumours, 14 benign lesions. Contrast-enhancement patterns and relationship of the mass with major vessels and bone were compared with histology on surgically excised samples. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were evaluated in discriminating active from aggressive tumours.

RESULTS

Sensitivity in differentiating aggressive tumours from active lesions was 89 %, specificity 84 %, PPV 90 %, NPV 82 %. The relationship between mass and major vessels/bone was fundamental for surgical strategy respectively in 40 % and in 58 % of malignant tumours.

CONCLUSION

Contrast-enhanced CT and CTA are effective in differentiating aggressive masses from active lesions in soft tissue and in depicting the relationship between tumour and adjacent bones and major vessels.

KEY POINTS

• Accurate delineation of vascular and bony involvement preoperatively is fundamental for a correct resection. • CT plays a critical role in differential diagnosis of soft tissue masses. • Contrast-enhanced CT and CT angiography are helpful in depicting tumoral vascular involvement. • CT is optimal for characterization of bone involvement in soft tissue malignancies.

Diffusion-weighted MRI for detection and differentiation of musculoskeletal tumorous and tumor-like lesions in pediatric patients

BACKGROUND

MRI is the diagnostic mainstay for detection and differentiation of musculoskeletal tumors. However, a projection regarding the biological dignity of lesions based on standard MRI sequences remains difficult and uncertain. This study was undertaken to analyse whether diffusion-weighted MRI (DWI) can distinguish between benign and malignant musculoskeletal tumorous and tumor-like lesions in pediatric patients.

METHODS

MR examinations of 44 consecutive pediatric patients (26 girls, mean age 11±6 years) including standard sequences and DWI (b=50/800 s/mm(2)) at 1.5 or 3 Tesla were retrospectively evaluated. The study group contained 10 patients with non-treated malignant tumors and 34 patients with benign lesions. Size, relative signal intensity and apparent diffusion coefficient (ADC, unit ×10(-3) mm(2)/s) were determined in one lesion per patient.

RESULTS

Mean ADC was 0.78±0.45×10(-3) mm(2)/s in patients with malignant tumors and 1.71±0.75 ×10(-3) mm(2)/s in patients with benign lesions (P<0.001). Relative operating characteristics (ROC) analysis showed a sensitivity of 90% and a specificity of 91% for malignancy, based on an ADC cut-off value of ≤1.03. On logistic regression, mean ADC and lesion size accounted for 62% of variability in benign vs. malignant tumors. For malignant tumors, the signal intensity ratio was higher on DWI than on T1w post-contrast images (P<0.002). Two cases of local tumor recurrence were diagnosed by DWI only.

CONCLUSIONS

DWI shows promising results for determination of biological dignity in musculoskeletal tumors. Mean ADC ≤1.03×10(-3) mm(2)/s is a strong indicator of malignancy at the first diagnosis. The use of DWI for early diagnosis of tumor recurrence in comparison with standard MRI sequences should be evaluated in prospective studies.