Evaluation of pediatric bone lesions

Aneurysmal Bone Cysts of the Craniofacial Origin: A Systematic Review

Objective

Aneurysmal bone cysts (ABCs) are blood-filled, locally destructive, benign bone tumors. Our objective was to conduct a systematic review outlining patient demographics, clinical characteristics, management, and outcomes of those with ABCs of the craniofacial bones.

Data Sources

Using PubMed, Cochrane, and Embase databases, 116 studies were included.

Review Methods

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a systematic review was conducted. Data including patient demographics, clinical characteristics, treatment strategies, and patient outcomes were collected.

Results

A total of 127 patients from 116 studies were identified. Age ranged from 8 months to 90 years, with a mean age of 19.0 years. The most commonly affected craniofacial locations were the mandible (n = 31, 24.4%), temporal bone (n = 21, 16.5%), and occipital bone (n = 14, 11.0%). The most common presenting symptoms included a nontender mass (n = 51, 40.2%), a tender mass (n = 31, 24.4%), and generalized headache (n = 30, 23.6%). Imaging modalities included computed tomography (CT) and magnetic resonance imaging (MRI) (n = 77, 60.6%), CT alone (n = 31, 24.4%), and MRI alone (n = 8, 6.2%). All patients underwent surgical resection, with 1 patient requiring adjuvant radiation in addition to surgery. In total, 121 patients were disease-free and symptom-free without evidence of recurrence (17.4-month mean follow-up, 5.4 months average time to first recurrence).

Conclusion

The current literature’s characterization of ABCs in craniofacial bones is limited to case reports and case series. Given the rarity of these tumors, head and neck surgeons may rely on systematic reviews such as the present analysis to guide management.

Surgical Management of Benign Tumors of the Proximal Fibula

Benign tumors of the proximal fibula are clinically notable, often resulting in pain, cosmetic defects, and potential neurovascular compromise. These symptomatic lesions warrant surgical consultation, but specific procedure selection remains a topic of ongoing discussion. The fibula is widely considered an expendable bone, which permits a greater variety of surgical options relative to other skeletal locations. As a result, some authors suggested en bloc resections without reconstruction as a viable first-line option to decrease tumor recurrence risk. However, wide resections may still result in diminished postoperative functionality compared with the standard intralesional and marginal approaches. Thus, surgical management remains a multifactorial decision, and often orthopaedic surgeons rely on past clinical experience or surgical preference within this unique tumor location. This detailed review will summarize the published literature and discuss the outcomes and indications of various surgical approaches for benign tumors of the proximal fibula. Emphasis will be placed on balancing tumor recurrence risk and postoperative functionality within the context of histologic diagnoses and surgical approaches.

Deep Learning for Classification of Bone Lesions on Routine MRI

Background

Radiologists have difficulty distinguishing benign from malignant bone lesions because these lesions may have similar imaging appearances. The purpose of this study was to develop a deep learning algorithm that can differentiate benign and malignant bone lesions using routine magnetic resonance imaging (MRI) and patient demographics.

Methods

1,060 histologically confirmed bone lesions with T1- and T2-weighted pre-operative MRI were retrospectively identified and included, with lesions from 4 institutions used for model development and internal validation, and data from a fifth institution used for external validation. Image-based models were generated using the EfficientNet-B0 architecture and a logistic regression model was trained using patient age, sex, and lesion location. A voting ensemble was created as the final model. The performance of the model was compared to classification performance by radiology experts.

Findings

The cohort had a mean age of 30±23 years and was 58.3% male, with 582 benign lesions and 478 malignant. Compared to a contrived expert committee result, the ensemble deep learning model achieved (ensemble vs. experts): similar accuracy (0·76 vs. 0·73, p=0·7), sensitivity (0·79 vs. 0·81, p=1·0) and specificity (0·75 vs. 0·66, p=0·48), with a ROC AUC of 0·82. On external testing, the model achieved ROC AUC of 0·79.

Interpretation

Deep learning can be used to distinguish benign and malignant bone lesions on par with experts. These findings could aid in the development of computer-aided diagnostic tools to reduce unnecessary referrals to specialized centers from community clinics and limit unnecessary biopsies.

Funding

This work was funded by a Radiological Society of North America Research Medical Student Grant (#RMS2013) and supported by the Amazon Web Services Diagnostic Development Initiative.

Limb Length Discrepancy and Angular Deformity due to Benign Bone Tumors and Tumor-like Lesions

Benign bone tumors and tumor-like lesions are frequently diagnosed in children and adolescents. The immature skeleton is at risk for growth disturbances and deformity because of the effects of the lesions on normal bone architecture and the physis. The development, manifestation, and severity of the limb length inequality and deformity differs between the various bone pathologies. Distraction osteogenesis, osteotomy, and guided growth are key tools in the treatment of limb inequality and deformity using a combination of external and internal fixation devices.

Accuracy of plain radiographs in diagnosing biopsy-proven malignant bone lesions

Background

The diagnosis of primary bone tumours is a three-fold approach based on a combination of clinical, radiological and histopathological findings. Radiographs form an integral part in the initial diagnosis, staging and treatment planning for the management of aggressive/malignant bone lesions. Few studies have been performed where the radiologist’s interpretation of radiographs is compared with the histopathological diagnosis.

Objectives

The study aimed to determine the frequency of bone tumours at a tertiary hospital in South Africa, and, using a systematic approach, to determine the sensitivity and specificity of radiograph interpretation in the diagnosis of aggressive bone lesions, correlating with histopathology. We also determined the inter-observer agreement in radiograph interpretation, calculated the positive and negative predictive values for aggressive/malignant bone tumours and computed the cumulative effect of multiple radiological signs to determine the yield for malignant bone tumours.

Method

A retrospective, descriptive and correlational study was performed, reviewing the histopathological reports of all biopsies performed on suspected aggressive bone lesions during a 3-year period from 2012 to 2014. The radiographs were interpreted by three radiologists using predetermined criteria. The sensitivity and specificity of the readers’ interpretation of the radiograph as ‘benign/non-aggressive’ or ‘aggressive/malignant’ were calculated against the histology, and the inter-rater agreement of the readers was computed using the Fleiss kappa values.

Results

Of the 88 suspected ‘aggressive or malignant’ bone tumours that fulfilled the inclusion criteria, 43 were infective or malignant and 45 were benign lesions at histology. Reader sensitivity in the diagnosis of malignancy/infective bone lesions ranged from 93% to 98% with a specificity of 53% – 73%. The average kappa value of 0.43 showed moderate agreement between radiological interpretation and final histology results. The four radiological signs with the highest positive predictive values were an ill-defined border, wide zone of transition, cortical destruction and malignant periosteal reaction. The presence of all four signs on radiography had a 100% yield for a malignant bone tumour or infective lesion.

Conclusion

The use of a systemic approach in the interpretation of bone lesions on radiographs yields high sensitivity but low specificity for malignancy and infection. The presence of benign bone lesions with an aggressive radiographic appearance necessitates continuation of the triple approach for the diagnosis of primary bone tumours.

JOURNAL CLUB: CT-Guided Bone Biopsies With Indeterminate Results in Pediatric Patients

OBJECTIVE

The objective of our study was to determine the frequency of indeterminate percutaneous CT-guided bone biopsy results in a pediatric population, the subsequent management of indeterminate biopsy results, and the factors associated with an indeterminate biopsy result.

MATERIALS AND METHODS

This retrospective study included 86 pediatric patients who underwent 89 CT-guided biopsies because of an unclear bone lesion in a tertiary referral center for bone tumors.

RESULTS

CT-guided bone biopsy results were indeterminate in 29 of 89 lesions (32.6%; 95% CI, 23.7-42.9%). Excluding two bone lesions with an uncertain diagnosis, all other 27 bone lesions proved to be benign on follow-up (0% malignancies; 95% CI, 0-12.5%). Compared with patients with diagnostic CT-guided bone biopsy results, patients with indeterminate biopsy results were significantly younger (median age, 14.0 vs 18.0 years; p = 0.0185), were female more frequently (72.4% vs 41.7%, p = 0.0007), and had bone lesion-related symptoms less frequently (62.1% vs 88.3%, p = 0.0094). Furthermore, bone lesions with indeterminate CT-guided bone biopsy results were significantly more frequently not visible at CT (24.1% vs 1.7%, p = 0.0021), more frequently had a sclerotic rim (40.9% vs 18.6%, p = 0.0477), less frequently showed cortical destruction (45.5% vs 72.9%, p = 0.0343), less frequently had an associated extraosseous soft-tissue mass (4.5% vs 32.2%, p = 0.0094), and were smaller (median diameter, 17.0 vs 31.0 mm; p = 0.0007) than bone lesions with diagnostic results; in addition, the maximum biopsy sample length was significantly shorter for bone lesions with indeterminate CT-guided bone biopsy results than for those with diagnostic results (mean length, 10.9 vs 17.8 mm; p = 0.0003).

CONCLUSION

A nondiagnostic CT-guided biopsy result in a child with an unclear bone lesion suggests benignity. Several clinical and CT features of bone lesions are associated with indeterminate CT-guided bone biopsy results.

Systematic approach to musculoskeletal benign tumors

The radiologic workup of musculoskeletal tumors can be both cost-efficient and extremely helpful to the referring clinician if one proceeds in a thoughtful and logical manner. It should be remembered that plain films remain the most reliable imaging method for assessment of both biological activity and probable histologic diagnosis of an osseous lesion. Further investigations are of help to determine the extent of lesion and to help in staging. In order to do this, we have found it useful to include an assessment of 10 determinants in the description of a tumor. If these determinants are accurately described, the correct diagnosis or at least a limited differential diagnosis usually becomes obvious.

Hip arthroscopy for intra-capsular benign tumors: a case series

The purpose of this study is to demonstrate the assessment of intra-capsular femoral head and neck tumors, and to describe the arthroscopic surgical technique used to resect and fill the bone defects. Three cases of benign femoral head and neck lesions are presented. Two benign enchondromas and one benign osteochondroma were resected arthroscopically. Traction was used in one case. Modified Harris Hip Score improved in all three cases to scores of 95 or greater with an average improvement of 16 points with a minimum follow up of 15 months. Arthroscopic surgical resection of intra-capsular femoral hip lesions offers an effective alternative to open resection. This technique offered good outcomes in the limited cohort. We suggest that arthroscopic resection of intra-capsular femoral hip lesions be considered in relevant cases as an alternative to open resection.

Treatment of bone defect with calcium phosphate cement subsequent to tumor curettage in pediatric patients

The aim of the present study was to investigate the mid- to long-term clinical performance of calcium phosphate cement (CPC) in the treatment of benign bone tumors in pediatric patients with a follow-up of at least 2-years. The cases of 33 patients with benign bone tumors treated by curettage and subsequent implantation of CPC were retrospectively reviewed. The patients consisted of 13 males and 20 females, with a median age of 13 years and median follow-up time of 79 months. All patients were alive at the time of review. No toxicity was detected in routine blood tests. Radiography was used to confirm that CPC was well adapted to the surrounding host bone, although the resorbability of CPC was not obtained for all patients at the final follow-up. Local tumor recurrence occurred in 4 patients. None of the patients reported post-operative fractures. In total, 6 patients required a second surgical procedure, as follows: 4 patients in whom local tumor recurrence occurred; 1 patient with post-operative superficial wound infection, who underwent wound debridement; and 1 patient that required the removal of CPC due to deep infection at the proximal humerus. All patients had regained full physical function without any pain at the final follow-up. The present study recommends that the properties of CPC should be taken into consideration and applied to the reconstruction of bone defects subsequent to curettage of bone tumors.

Case 2: a 10-year-old girl with hip pain

In this continuing series designed for pediatric radiology trainees, the imaging management of hip pain and a discovered bony mass are dissected through a specific case of a preadolescent.

Pediatric bone sarcoma: diagnostic performance of ¹⁸F-FDG PET/CT versus conventional imaging for initial staging and follow-up

OBJECTIVE

The purpose of this study was to compare the diagnostic performance of (18)F-FDG PET/CT and conventional imaging for staging and follow-up of pediatric osteosarcoma and skeletal Ewing sarcoma.

MATERIALS AND METHODS

We calculated sensitivity, specificity, and accuracy of PET/CT and conventional imaging (CT, MRI, bone scanning) for sites of disease and number of lesions. Diagnostic benefit, defined as better characterization of lesions, was evaluated on a per-scan basis, comparing PET/CT and conventional imaging.

RESULTS

A total of 412 lesions were characterized by imaging in 64 patients (20, osteosarcoma; 44, Ewing sarcoma). For osteosarcoma patients PET/CT was available only at follow-up, where it proved more accurate than conventional imaging for the detection of bone lesions (accuracy, 95% vs 67% for CT and 86% for MRI) and complementary to CT in evaluating lung nodules (sensitivity, 84% vs 94%; specificity, 79% vs 71%) with diagnostic benefit in 18% of examinations. In patients with Ewing sarcoma, PET/CT tended to perform better during follow-up than at initial staging (accuracy, 85% vs 69%). For lung findings, PET/CT was more specific than CT but was less sensitive. The diagnostic benefit of PET/CT was greater at staging (28%) than during followup (9%). On a per-patient basis, PET/CT provided diagnostic benefit in 21 of 44 patients with Ewing sarcoma and nine of 20 patients with osteosarcoma at least once during clinical management.

CONCLUSION

FDG PET/CT provides diagnostic benefit in Ewing sarcoma and osteosarcoma, with the exception of small lung nodules. Prospective studies are needed to define the best imaging algorithm and combination of tests in the staging and follow-up of patients with pediatric bone sarcoma.

Role of apparent diffusion coefficients with diffusion-weighted magnetic resonance imaging in differentiating between benign and malignant bone tumors

Background

Benign and malignant bone tumors can present similar imaging features. This study aims to evaluate the significance of apparent diffusion coefficients (ADC) in differentiating between benign and malignant bone tumors.

Methods

A total of 187 patients with 198 bone masses underwent diffusion-weighted (DW) magnetic resonance (MR) imaging. The ADC values in the solid components of the bone masses were assessed. Statistical differences between the mean ADC values in the different tumor types were determined by Student’s t-test.

Results

Histological analysis showed that 84/198 (42.4%) of the bone masses were benign and 114/198 (57.6%) were malignant. There was a significant difference between the mean ADC values in the benign and malignant bone lesions (P <0.05). However, no significant difference was found in the mean ADC value between non-ossifying fibromas, osteofibrous dysplasia, and malignant bone tumors. When an ADC cutoff value ≥1.10 × 10⁻³ mm²/s was applied, malignant bone lesions were excluded with a sensitivity of 89.7%, a specificity of 84.5%, a positive predictive value of 82.6%, and a negative predictive value of 95.3%.

Conclusions

The combination of DW imaging with ADC quantification and T2-weighted signal characteristics of the solid components in lesions can facilitate differentiation between benign and malignant bone tumors.

Computerized tomography in pediatric oncology

Computerized tomography (CT) is an extremely powerful imaging modality, which provides extremely valuable information for the diagnosis, staging, and management of pediatric solid tumors. In recent years, the concern of potential risks associated with ionizing radiation from diagnostic imaging - especially from CT - has greatly increased. In children with cancer the radiation burden from CT studies can easily accumulate because of repeated studies for disease staging, assessment of response to therapy, and follow up. The purpose of this article is to review the role of CT and its imaging key points for diagnosis, staging and planning surgical excision of common extracranial pediatric tumors, according to protocol specific imaging guidelines. The issue of the radiation burden from CT in children with cancer, and criteria of good practice to reduce it, will also be discussed.

Rheumatic manifestations of primary and metastatic bone tumors and paraneoplastic bone disease

Bone tumors can show a wide range of nonspecific rheumatic manifestations. The presence of unexplained or atypical chronic bone pain, an enlarging bone mass, neurovascular compression syndromes, or pathologic fractures should alert us to the possibility of a bone tumor causing these symptoms. These patients must undergo a complete physical examination; adequate imaging; and, if needed, a biopsy to confirm their diagnosis and offer them an opportune treatment. In addition, bone tumors and other malignancies can present remote clinical manifestations and unusual laboratory findings (eg, HOA, hypophosphatemia, hyperphosphaturia, and hypercalcemia) that may be the first and early manifestation of an occult cancer. These findings should motivate a cancer screening according to age, sex, and personal history. Cancer therapies also have a big impact on bone health, increasing the risk of osteoporosis, osteomalacia, and/or osteonecrosis. Rheumatologists should be aware of possible long-term adverse events of cancer treatment to avoid future complications.