PET/CT of Osteosarcoma and Ewing Sarcoma

Predictors of pulmonary metastases on chest computed tomography in children and adolescents with osteosarcoma-tips for qualifying patients for thoracotomy

BACKGROUND

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Lungs are the most frequent and often the only site of metastatic disease. The presence of pulmonary metastases is a significant unfavourable prognostic factor. Thoracotomy is strongly recommended in these patients, while computed tomography (CT) remains the gold imaging standard. The purpose of our study was to create tools for the CT-based qualification for thoracotomy in osteosarcoma patients in order to reduce the rate of useless thoracotomies.

METHODS

Sixty-four osteosarcoma paediatric patients suspected of lung metastases on CT and their first-time thoracotomies (n = 100) were included in this retrospective analysis. All CT scans were analysed using a compartmental evaluation method based on the number and size of nodules. Calcification and location of lung lesions were also analysed. Inter-observer reliability between two experienced radiologists was assessed. The CT findings were then correlated with the histopathological results of thoracotomies. Various multivariate predictive models (logistic regression, classification tree and random forest) were built and predictors of lung metastases were identified.

RESULTS

All applied models proved that calcified nodules on the preoperative CT scan best predict the presence of pulmonary metastases. The rating of the operated lung on the preoperative CT scan, dependent on the number and size of nodules, and the total number of nodules on this scan were also found to be important predictors. All three models achieved a relatively high sensitivity (72-92%), positive predictive value (81-90%) and accuracy (74-79%). The positive predictive value of each model was higher than of the qualification for thoracotomy performed at the time of treatment. Inter-observer reliability was at least substantial for qualitative variables and excellent for quantitative variables.

CONCLUSIONS

The multivariate models built and tested in our study may be useful in the qualification of osteosarcoma patients for metastasectomy through thoracotomy and may contribute to reducing the rate of unnecessary invasive procedures in the future.

A case of epithelioid osteoblastoma of the thoracic vertebra in a 12-year-old male: a case report and review of literature

Introduction and importance

Osteoblastoma (OB) is a rare benign bone tumor, representing less than 1% of all bone neoplasms. In contrast to the typical OB, a smaller subset known as 'epithelioid osteoblastoma (EO)' exhibits a distinctive inclination for local invasion and recurrence. This rare variant can pose diagnostic challenges, particularly due to its unclear clinical and radiological presentation.

Case presentation

This study details a clinical case of a 12-year-old boy experiencing pain from a lytic bone tumor located in the thoracic vertebrae (T3-T4), initially suggesting malignancy. Following extensive curettage, histopathological analysis confirmed the diagnosis of EO through immunohistochemical staining. Subsequent follow-up at 3 months revealed the absence of no pain or recurrence of the lesion.

Clinical discussion

Distinguishing EO from a malignant tumor requires a multidisciplinary approach, considering clinical, radiographic, and histological features that differentiate the two entities.

Conclusion

The goal of this case presentation is to increase awareness regarding this recurrent tumor variant, which poses diagnostic challenges, particularly in distinguishing it from malignant tumors, including osteosarcoma.

The Diagnosis and Treatment of Osteosarcoma and Ewing's Sarcoma in Children and Adolescents

BACKGROUND

Osteosarcoma and Ewing's sarcoma in children and adolescents require age-specific interdisciplinary diagnosis and treatment to achieve optimal therapeutic outcomes.

METHODS

The diagnosis and treatment of malignant bone tumors in childhood and adolescence are presented in the light of publications retrieved by a selective search, pertinent guidelines, and the authors' extensive experience in an interdisciplinary cancer center.

RESULTS

Bone sarcomas make up approximately 5% of all malignancies in children and adolescents; the most common types are Ewing's sarcoma and osteosarcoma. Patients are often not referred to a specialized center until long after the onset of symptoms, as they and their physicians rarely consider the possibility of a bone tumor, and the symptoms are often trivialized. Bone pain of unknown origin, swelling, and functional limitations should be investigated with conventional x-rays. Lesions of unclear origin should be biopsied after a meticulous clinical and radiologic evaluation. Multimodal treatment consists of neo - adjuvant chemotherapy, limb-preserving resection if possible, and radiotherapy where indicated. In multicenter studies, patients with osteosarcoma achieve event-free survival in 64% of cases if their disease is localized, and 28% if it is metastatic; the corresponding figures for patients with Ewing's sarcoma are 80% and 27%, respectively.

CONCLUSION

With implementation of the current treatment recommendations, most children and adolescents with malignant bone tumors can be treated successfully with curative intent. These patients should be referred to a sarcoma center for diagnosis and treatment.

Imaging of pediatric bone tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

Malignant primary bone tumors are uncommon in the pediatric population, accounting for 3%-5% of all pediatric malignancies. Osteosarcoma and Ewing sarcoma comprise 90% of malignant primary bone tumors in children and adolescents. This paper provides consensus-based recommendations for imaging in children with osteosarcoma and Ewing sarcoma at diagnosis, during therapy, and after therapy.

The Impact of PET/CT on Paediatric Oncology

This review paper will discuss the use of positron emission tomography/computed tomography (PET/CT) in paediatric oncology. Functional imaging with PET/CT has proven useful to guide treatment by accurately staging disease and limiting unnecessary treatments by determining the metabolic response to treatment. 18F-Fluorodeoxyglucose (2-[18F]FDG) PET/CT is routinely used in patients with lymphoma. We highlight specific considerations in the paediatric population with lymphoma. The strengths and weaknesses for PET/CT tracers that compliment Meta-[123I]iodobenzylguanidine ([123I]mIBG) for the imaging of neuroblastoma are summarized. 2-[18F]FDG PET/CT has increasingly been used in the staging and evaluation of disease response in sarcomas. The current recommendations for the use of PET/CT in sarcomas are given and potential future developments and highlighted. 2-[18F]FDG PET/CT in combination with conventional imaging is currently the standard for disease evaluation in children with Langerhans-cell Histiocytosis (LCH) and the non-LCH disease spectrum. The common pitfalls of 2-[18F]FDG PET/CT in this setting are discussed.

Advances in the Biological Functions and Mechanisms of miRNAs in the Development of Osteosarcoma

Osteosarcoma is one of the most common primary malignant bone tumors, mainly occurring in children and adolescents, and is characterized by high morbidity and poor prognosis. MicroRNAs, a class of noncoding RNAs consisting of 19 to 25 nucleotides, are involved in cell proliferation, invasion, metastasis, and apoptosis to regulate the development and progression of osteosarcoma. Studies have found that microRNAs are closely related to the diagnosis, treatment, and prognosis of osteosarcoma patients and have an important role in improving drug resistance in osteosarcoma. This paper reviews the role of microRNAs in the pathogenesis of osteosarcoma and their clinical value, aiming to provide a new research direction for diagnosing and treating osteosarcoma and achieving a better prognosis.

Mediastinal lymph node metastasis as a single expression of disease relapse in Ewing's sarcoma: multidisciplinary approach of two consecutive cases

Ewing's sarcoma of the bone is a rare, highly aggressive tumor that typically affects children and young adults. Progress in the treatment of Ewing's sarcoma has improved survival from about 10%, before the introduction of chemotherapy, to about 75% today for patients with localized tumors. On the contrary, metastatic disease still has a poor prognosis, and a multidisciplinary approach is essential to improve the outcome. Molecular techniques and new imaging modalities are affecting the diagnosis and classification of patients with Ewing's sarcoma. The most frequent sites of metastases in Ewing's sarcoma include lungs, bones and bone marrow. Lymph nodes are a rare site of metastatic spread, particularly in the mediastinum. In this report, we present two consecutive cases of patients with Ewing's Sarcoma, diagnosed, and treated at our institute. We focused particularly on the rarity of the atypical presentation of the disease and on the synergistic strategy to adopt as a model of networking in treating patients with rare diseases.

An Approach to Undiagnosed Bone Tumors

The radiographic appearance of primary bone tumors is important for initial diagnosis and often augments histopathological analysis. The original grading system relied on the radiographic analysis of the margin of the lesions to determine tumor aggression, which often corresponds with malignant potential. The recently developed, modified Lodwick-Madewell grading system also incorporates the appearance of lesion margins on radiographs but also considers the change in margins on serial radiographs and includes a category for clinically suspected, radiographically occult, aggressive lesions. This article reviews the prior and modified grading systems, and the concepts necessary for proper interpretation of the initial appearance of bone tumors which often determines the radiologist's recommendation for biopsy or follow-up imaging.

Clinical and Prognostic Role of 18F-FDG PET/CT in Pediatric Ewing Sarcoma

Ewing sarcoma (ES) is one of the most common pediatric solid tumors with aggressive behavior and unfavorable survival. In this study, we evaluated the diagnostic accuracy of baseline and restaging fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) scans and their possible prognostic role in pediatric ES. We evaluated 17 patients who underwent a total of 27 18F-FDG-PET/CT scans (10 for staging and 17 for restaging). The PET images were analyzed visually and semiquantitatively by measuring SUVmean, SUVmax, SUVlbm, SUVbsa, MTV, and TLG. Moreover, PET/CT results were compared with other conventional imaging (CI) results. Among 10 baseline PET/CT scan results, 9 were positive and 1 not valuable by interference; baseline PET/CT and CI were concordant in 7 cases and discordant in 2, with pulmonary micrometastases not detected by PET/CT. Among 17 restaging PET/CT scan results, 9 were positive and 8 negative; CI and restaging PET/CT were concordant in 9 cases and discordant in 8. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of restaging 18F-FDG-PET/CT were 73%, 83%, 89%, 62.5%, and 76%, respectively. After a median follow-up of 20 months, relapse/progression occurred in 8 patients and death in 5. A positive 18F-FDG-PET/CT at restaging was significantly associated with shorter overall survival compared with unremarkable PET/CT at the same timepoint, but not with progression-free survival. Instead, metabolic PET/CT features were not correlated with outcome. 18F-FDG-PET/CT showed a good diagnostic performance in pediatric ES; except for pulmonary micrometastases, PET/CT was better than CI at restaging. Only restaging PET/CT result was significantly correlated with overall survival.

Effectiveness of 18F-FDG PET/CT in the diagnosis and staging of osteosarcoma: a meta-analysis of 26 studies

BACKGROUND

Multiple trials have attempted to assess the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in osteosarcoma with results remaining inconclusive. This study aims to investigate the effectiveness of 18F-FDG PET and PET/CT in the diagnosis, staging, recurrence and metastasis formation observations of osteosarcoma through systematic review followed by meta-analysis.

METHODS

Three electronic databases, Medline/PubMed, Embase and the Cochrane Library were utilized in this study. Eligible studies that assessed the performance of 18F-FDG PET/CT for the diagnosis, staging, restaging and recurrence monitoring of osteosarcoma were retrieved utilizing specific search criteria. After screening and diluting out the non-conforming articles, all relevant articles and their data were identified and extracted to calculate the summary metrics involving sensitivity, specificity, diagnostic odd ratio (DOR), and area under the curve (AUC) to determine the effectiveness of 18F-FDG PET in diagnosing osteosarcoma clinically.

RESULTS

Out of 1976 articles searched, twenty-six studies were identified that were viable. All data from these articles, utilized in the quantitative analyses, showed after meta-analysis that when utilizing 18F-FDG PET or PET/CT it was better with a success rate of 90-100% for detecting primary lesions and distant metastases of patients with osteosarcoma. Similar results were also obtained for detecting lung and bone metastases in a subgroup analysis.

CONCLUSIONS

As such the investigation demonstrated that 18F-FDG PET and PET/CT are very accurate for the diagnosis, staging and recurrence monitoring of osteosarcoma. 18F-FDG-avid lesions should be further examined in osteosarcoma, especially for suspicious lung lesions.

Pediatric Musculoskeletal Imaging: The Indications for and Applications of PET/Computed Tomography

The use of PET/computed tomography (CT) for the evaluation and management of children, adolescents, and young adults continues to expand. The principal tracer used is 18F-fluorodeoxyglucose and the principal indication is oncology, particularly musculoskeletal neoplasms. The purpose of this article is to review the common applications of PET/CT for imaging of musculoskeletal issues in pediatrics and to introduce the use of PET/CT for nononcologic issues, such as infectious/inflammatory disorders, and review the use of 18F-sodium fluoride in trauma and sports-related injuries.

Triple primary malignancies of surface osteosarcoma of jaw, myelodysplastic syndrome and colorectal cancer as a second primary cancer detected by PET2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography: A case report

Second primary malignancy (SPM) is a severe issue for cancer survivors, particularly for osteosarcoma (OS) survivors. To date, the associations between subsequent SPM and OS have been well reported. Hematogenic and solid malignancies tend to occur following OS treatment. Reportedly, 2-[¹⁸F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is mainly used in OS patients for initial cancer staging, to evaluate the response of neoadjuvant chemotherapy, and when recurrence or metastasis is clinically suspected. The present case report describes a 70-year-old man diagnosed with three primary malignancies: jaw OS, myelodysplastic syndrome and colorectal adenocarcinoma. To the best of our knowledge, this combination of malignancies has not been reported previously. Until now, there is no specific protocol of postoperative FDG-PET for OS patients. Few studies have described OS follow-up methods; therefore, there is no consensus on proper follow-up methods. In the present case report, the colorectal early-stage SPM was observed, without any symptoms, by FDG-PET/computed tomography. To avoid overlooking solid SPMs, it is suggested that FDG-PET should be performed in the long-term follow-up of OS patients.