Assessment of Medical Students' Knowledge of Imaging Methods for Bone Sarcomas.

Cancer is a leading cause of death in Brazil and worldwide. However, Brazilian medical education fails to include oncology as an essential topic. This creates a gap between the health status of the population and medical education. Bone sarcomas fall into both the group of malignant neoplasms and rare diseases and are thus doubly influenced by misinformation. To assess medical students' knowledge of imaging diagnostic methods for bone sarcomas. A cross-sectional, quantitative study was undertaken by obtaining the responses of medical students to a questionnaire containing radiographic images and questions about the radiological aspects of bone sarcomas. The categorical variables were compared using the chi-square test. The level of significance was 5% for all the tests. SPSS software version 25.0 was used for the analysis. A total of 325 responses were collected, with 72% of the participants having no interest in oncology and 55.6-63.9% not knowing how to diagnose a periosteal reaction on bone radiography. Only 11.1-17.1% of the students correctly interpreted the radiographic image of osteosarcoma. Medical students fail to correctly interpret images of bone sarcomas. It is important to promote oncology undergraduate education in general and to include the approach to bone sarcomas in this context.

CT features of osteosarcoma lung metastasis: a retrospective study of 127 patients.

OBJECTIVE: Osteosarcoma lung metastases have a wide variety of CT presentations, representing a challenge for radiologists. Knowledge of atypical CT patterns of lung metastasis is important to differentiate it from benign lung disease and synchronous lung cancer, as well as to determine the extent of primary disease. The objective of this study was to analyze CT features of osteosarcoma lung metastasis before and during chemotherapy. METHODS: Two radiologists independently reviewed chest CT images of 127 patients with histopathologically confirmed osteosarcoma treated between May 10, 2012 and November 13, 2020. The images were divided into two groups for analysis: images obtained before chemotherapy and images obtained during chemotherapy (initial CT examination). RESULTS: Seventy-five patients were diagnosed with synchronous or metachronous lung metastases. The most common CT findings were nodules (in 95% of the patients), distributed bilaterally (in 86%), with no predominance regarding craniocaudal distribution (in 71%). Calcification was observed in 47%. Less common findings included intravascular lesions (in 16%), cavitation (in 7%), and the halo sign (in 5%). The primary tumor size was significantly greater (i.e., > 10 cm) in patients with lung metastasis. CONCLUSIONS: On CT scans, osteosarcoma lung metastases typically appear as bilateral solid nodules. However, they can have atypical presentations, with calcification being the most common. Knowledge of the typical and atypical CT features of osteosarcoma lung metastasis could play a key role in improving image interpretation in these cases.

Hallazgos tomográficos en paciente con osteosarcoma condroblástico mandibular recidivante de alto grado / Tomographic Findings in a Patient with Recurrent High - Grade Chondroblastic Osteosarcoma of the Jaw

Hallazgos de lesión expansiva que compromete la región hemifacial izquierda, con plano de clivaje sobre las estructuras adyacentes, que genera cambios líticos sobre la rama mandibular izquierda, en el cuerpo y la región del cóndilo mandibular. La lesión tiene un diámetro aproximado de 12,5 cm, con múltiples calcificaciones en su interior, que genera efecto de masa sobre las estructuras del piso de la boca y desvía la columna de la vía aérea en sentido dextroconvexo, sin evidenciar estenosis significativa(AU)

Peri-osteosarcoma adipose computed tomography attenuation and volume for predicting chemotherapy response in pediatric patients.

BACKGROUND: The chemosensitivity of osteosarcoma patients to MTX is closely related to prognosis. There is currently a lack of advance prediction methods for MTX sensitivity. OBJECTIVE: We proposed novel peri-osteosarcoma fat parameters based on computed tomography (CT) to evaluate the chemotherapy response preoperatively and calculate the correlation between image characteristics and methotrexate (MTX) blood concentration and systemic inflammation. MATERIALS AND METHODS: Pediatric patients with osteosarcoma (OS) who were treated with high-dose MTX were retrospectively studied and grouped according to postoperative Huvos classification. Clinical data were collected and reviewed. Image characteristics including peri-osteosarcoma fat volume and fat attenuation index were measured using the threshold method based on CT images. Statistical significance, correlation and prediction performance were performed. RESULTS: Eighteen patients (good response (GR) group/poor response (PR) group: 10/8) was enrolled. MTX peak value at 6 h differed significantly between the two groups which was significantly higher in GR group (745.1 µmol/L vs 529.0 µmol/L p = 0.001). Peri-osteosarcoma fat attenuation index was significantly lower in GR group compared with that in PR group (- 104.90 vs. - 97.19, p < 0.0001). MTX blood concentration at 6 h negatively correlated with peri-osteosarcoma fat attenuation index (R = - 0.519, p = 0.027). In addition, 6 h MTX blood concentration (OR 0.974; 95% CI 0.951-0.998, p = 0.037) and FAI (OR 2.108; 95% CI 1.047-4.243, p = 0.037) were, respectively, independently related to good response to chemotherapy. The prediction performance on chemotherapy response of peri-osteosarcoma fat attenuation index and 6 h MTX blood concentration were both good with the comparable area under the ROC curve (0.950, 95% CI 0.856-1.000 and 0.963, 95% CI 0.878-1.00). CONCLUSIONS: Peri-osteosarcoma fat parameters based on CT were associated with the chemotherapy response and the MTX blood concentration, but not with the systemic inflammation. Combined with the requirement of current clinical practice, peri-osteosarcoma fat parameters may have the potential to be valuable image characteristics for monitoring chemotherapy response in OS pediatric patients.

Machine learning-based CT radiomics features for the prediction of pulmonary metastasis in osteosarcoma.

OBJECTIVE: This study aims to build machine learning-based CT radiomic features to predict patients developing metastasis after osteosarcoma diagnosis. METHODS AND MATERIALS: This retrospective study has included 81 patients with a histopathological diagnosis of osteosarcoma. The entire dataset was divided randomly into training (60%) and test sets (40%). A data augmentation technique for the minority class was performed in the training set, along with feature's selection and model's training. The radiomic features were extracted from CT's image of the local osteosarcoma. Three frequently used machine learning models tried to predict patients with lung metastases (MT) and those without lung metastases (non-MT). According to the higher area under the curve (AUC), the best classifier was chosen and applied in the testing set with unseen data to provide an unbiased evaluation of the final model. RESULTS: The best classifier for predicting MT and non-MT groups used a Random Forest algorithm. The AUC and accuracy results of the test set were bulky (accuracy of 73% [ 95% coefficient interval (CI): 54%; 87%] and AUC of 0.79 [95% CI: 0.62; 0.96]). Features that fitted the model (radiomics signature) derived from Laplacian of Gaussian and wavelet filters. CONCLUSIONS: Machine learning-based CT radiomics approach can provide a non-invasive method with a fair predictive accuracy of the risk of developing pulmonary metastasis in osteosarcoma patients. ADVANCES IN KNOWLEDGE: Models based on CT radiomic analysis help assess the risk of developing pulmonary metastases in patients with osteosarcoma, allowing further studies for those with a worse prognosis.

Osteosarcoma of the hard palate in a dog - case report / [Osteossarcoma em palato duro de cão - relato de caso]

The osteosarcoma (OSA) is the most diagnosed primary bone cancer in canine patients. This work reports a case of a canine, six years old, mongrel, female, intact, with an OSA in the hard palate. Physical examination detected a firm mass in the palate. Thoracic radiographs, hematological and biochemical exams, histopathological exams and computed tomography were requested. A chondroblastic OSA was diagnosed and the tumor was characterized by immunohistochemistry. There was never evidence of metastasis in this case. The treatment consisted of the combination of conventional chemotherapy, metronomic chemotherapy, and palliative care, aiming at greater survival and well-being of the patient since surgical excision was not possible due to the location and extension of the tumor. Osteogenic sarcomas of the hard palate are rarely seen and described in the literature. In this article we present a characterization of the osteosarcoma with uncommon localization in the hard palate.(AU)

O osteossarcoma (OSA) é a neoplasia óssea primária mais diagnosticada em pacientes caninos. Este trabalho relata o caso de um canino, com seis anos de idade, sem raça definida, fêmea, não castrado, apresentando OSA em região de palato duro. Ao exame clínico, constatou-se uma massa de consistência firme em região palatina. Além do exame clínico, foram solicitadas radiografias torácicas, exames hematológicos e bioquímicos, exames histopatológicos e tomografia computadorizada. Fora então dado o diagnóstico de OSA condroblástico, e o tumor foi caracterizado pela imuno-histoquímica. Não foram observadas evidências de metástases nesse caso. O tratamento instituído consistiu na combinação de quimioterapia convencional, quimioterapia metronômica e cuidados paliativos, almejando maior sobrevida e bem-estar do paciente, uma vez que a excisão cirúrgica não foi possível devido à localização e à extensão do tumor. Neste artigo, apresentou-se uma caracterização do osteossarcoma com localização incomum no palato duro.(AU)

A rare case of a metastatic giant cell-rich osteosarcoma of the mandible: Update and differential diagnostic considerations.

A metastatic giant cell-rich osteosarcoma (GCRO) to the jaws is an exceedingly rare neoplasm. To date, fewer than 10 cases have been reported in the English language literature. In this article, we describe an additional case of a metastatic GCRO that presented the diagnostic challenge of a painless mass in the posterior mandible of a 19-year-old girl who exhibited rapid and aggressive local growth. The lesion was confirmed radiologically as an ill-defined expansive osteolytic mass showing cortical perforation. Microscopically, the presence of osteoclast-like giant cells permeated with atypical oval and rounded mesenchymal cells in a fibrovascular stroma, cellular atypia, and scarce osteoid formation were observed. Immunohistochemistry revealed the Ki-67 proliferative index in 50% of positive cells, positivity for vimentin and CD68, as well as scarce positivity for CDK4. The patient's medical history involved a GCRO in the proximal ulna. This report highlights the aggressive behavior of GCRO and its high capacity for metastasis to different parts of the body. Clinicians, pathologists, and surgeons should be aware of the giant cell-rich variant of osteosarcoma of the jaws, an imminent "wolf in a sheep's skin", because its indolent but unrelenting growth and dissemination, with radiographic and histologic characteristics that may represent a diagnostic pitfall regarding aggressive central giant cell lesions of the jaws.

Fibroblastic osteosarcoma in a white-eared opossum (Didelphis albiventris) / Osteossarcoma fibroblástico em gambá-de-orelha-branca (Didelphis albiventris)

Osteosarcoma is characterized by the production of osteoid or woven bone, using neoplastic osteoblasts. It is the most common primary bone neoplasm in canines and humans. This neoplasm was previously reported in all vertebrate classes, including a wide variety of mammals. However, there is no case report describing this neoplasm in Didelphis albiventris. Therefore, the objective of this manuscript is to describe the clinical-pathological aspects of fibroblastic osteosarcoma in D. albiventris. A wild adult male white-eared opossum (D. albiventris) arrived at the zoological park of the "Universidade de Caxias do Sul" with a swollen left thoracic limb. After a general clinical examination, the animal was transferred to the Veterinary Clinic of "Universidade de Caxias do Sul" for radiographic examination of the left thoracic limb and thorax. Additionally, some material was collected through fine needle aspiration (FNA) for cytologic evaluation. The radiographic findings and cytologic evaluation indicated osteosarcoma. The animal was euthanized due to severe clinical conditions and guarded prognosis. During necropsy, macroscopic analysis of the viscera was performed, fragments of various organs were collected and fixed in 10% neutral buffered formalin. All fragments were processed following routine histological techniques. The histopathological evaluation confirmed osteosarcoma, which was classified as a fibroblastic subtype. Case reports are crucial for the knowledge of incidence, prevalence, and behavior of the current mentioned disease, as well as other diseases, in species with such limited information. In order to obtain a decisive diagnosis, a few different examination methods were associated. Although the observations presented are based on a single case, this neoplasm had a similar clinical presentation to that described in other species.(AU)

O osteossarcoma é caracterizado pela produção de osteoide ou osso imaturo, por osteoblastos neoplásicos. É a neoplasia óssea primária mais comum em caninos e humanos. Essa neoplasia já foi relatada em todas as classes de vertebrados, incluindo uma grande variedade de mamíferos. Não havendo descrição dessa neoplasia até o momento em Didelphis albiventris. O objetivo deste trabalho é descrever aspectos clínico-patológicos de um caso de osteossarcoma fibroblástico em D. albiventris. Chegou para atendimento no Zoológico da Universidade de Caxias do Sul um gambá-de-orelha-branca (D. albiventris), macho, adulto, de vida livre com aumento de volume no membro torácico esquerdo. Após avaliação clínica geral, o animal foi encaminhado para a Clínica Veterinária da Universidade de Caxias do Sul para realização de radiografia do membro torácico esquerdo e de tórax, sendo também realizada coleta de material por punção aspirativa por agulha fina (PAAF) para avaliação citológica. Os achados radiográficos e da avaliação citológica foram sugestivos de osteossarcoma. Devido ao estado clínico grave e prognóstico reservado optou-se pela eutanásia. Durante a necropsia realizou-se a análise macroscópica das vísceras, foram coletados fragmentos de diversos órgãos, fixados em formalina 10%, processados pelas técnicas histológicas de rotina. Na avaliação histopatológica confirmou-se a suspeita de osteossarcoma sendo classificado no subtipo fibroblástico. A descrição de relatos é fundamental para conhecimento da incidência, prevalência e comportamento desta e de outras doenças em espécies que as informações são limitadas. A associação de diferentes métodos de exames foram necessários para a obtenção de um diagnóstico definitivo. Embora as observações apresentadas se baseiem em um caso único, esta neoplasia possuiu apresentação clínica semelhante a descrita em outras espécies.(AU)

Manual and semiautomatic segmentation of bone sarcomas on MRI have high similarity.

The aims of this study were to evaluate the intra- and interobserver reproducibility of manual segmentation of bone sarcomas in magnetic resonance imaging (MRI) studies and to compare manual and semiautomatic segmentation methods. This retrospective study included twelve osteosarcoma and eight Ewing sarcoma MRI studies performed prior to any therapeutic intervention. All cases were histopathologically confirmed. Three radiologists used 3D-Slicer software to perform manual segmentation of bone sarcomas in a blinded and independent manner. One radiologist segmented manually and also performed semiautomatic segmentation with the GrowCut tool. Segmentation exercises were timed for comparison. The dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to evaluate similarity between the segmentation results and further statistical analyses were performed to compare DSC, HD, and volumetric results. Manual segmentation was reproducible with intraobserver DSC varying from 0.83 to 0.97 and HD from 3.37 to 28.73 mm. Interobserver DSC of manual segmentation showed variation from 0.73 to 0.97 and HD from 3.93 to 33.40 mm. Semiautomatic segmentation compared to manual segmentation resulted in DSCs of 0.71-0.96 and HDs of 5.38-31.54 mm. Semiautomatic segmentation required significantly less time compared to manual segmentation (P value ≤0.05). Among all situations compared, tumor volumetry did not show significant statistical differences (P value >0.05). We found excellent intra- and interobserver agreement for manual segmentation of osteosarcoma and Ewing sarcoma. There was high similarity between manual and semiautomatic segmentation, with a significant reduction of segmentation time using the semiautomatic method.

Manual and semiautomatic segmentation of bone sarcomas on MRI have high similarity

The aims of this study were to evaluate the intra- and interobserver reproducibility of manual segmentation of bone sarcomas in magnetic resonance imaging (MRI) studies and to compare manual and semiautomatic segmentation methods. This retrospective study included twelve osteosarcoma and eight Ewing sarcoma MRI studies performed prior to any therapeutic intervention. All cases were histopathologically confirmed. Three radiologists used 3D-Slicer software to perform manual segmentation of bone sarcomas in a blinded and independent manner. One radiologist segmented manually and also performed semiautomatic segmentation with the GrowCut tool. Segmentation exercises were timed for comparison. The dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to evaluate similarity between the segmentation results and further statistical analyses were performed to compare DSC, HD, and volumetric results. Manual segmentation was reproducible with intraobserver DSC varying from 0.83 to 0.97 and HD from 3.37 to 28.73 mm. Interobserver DSC of manual segmentation showed variation from 0.73 to 0.97 and HD from 3.93 to 33.40 mm. Semiautomatic segmentation compared to manual segmentation resulted in DSCs of 0.71−0.96 and HDs of 5.38−31.54 mm. Semiautomatic segmentation required significantly less time compared to manual segmentation (P value ≤0.05). Among all situations compared, tumor volumetry did not show significant statistical differences (P value >0.05). We found excellent intra- and interobserver agreement for manual segmentation of osteosarcoma and Ewing sarcoma. There was high similarity between manual and semiautomatic segmentation, with a significant reduction of segmentation time using the semiautomatic method.

Primary osteosarcoma of the skull in teenager.

Osteosarcoma of the skull is a rare primary malignant bone tumour in children, representing 1-2% of all cranial tumours. We describe a case of a 17-year-old adolescent with chondroblastic osteosarcoma of the parietal-occipital bone and no distant metastases at presentation treated with neoadjuvant chemotherapy, surgery and, later, concurrent chemoradiotherapy. The patient suffered progressive disease and died 15 months after diagnosis. There are at least 15 paediatric cases of osteosarcoma of the skull described in the literature. Due to its rarity, there are no broad prospective studies on this entity, which has distinctive features when compared to other craniofacial tumours, carrying a worse prognosis. Complete surgical resection is needed for long-term survival, whereas chemotherapy and radiotherapy have still questionable indications.

What Are the Complications of Allograft Reconstructions for Sarcoma Resection in Children Younger Than 10 Years at Long-term Followup?

BACKGROUND: Preservation of limb function after resection of malignant bone tumors in skeletally immature children is challenging. Resection of bone sarcomas and reconstruction with an allograft in patients younger than 10 years old is one reconstructive alternative. However, long-term studies analyzing late complications and limb length discrepancy at skeletal maturity are scarce; this information would be important, because growth potential is altered in these patients owing to the loss of one physis during tumor resection. QUESTIONS/PURPOSES: At a minimum followup of 10 years after reconstructions in children younger than 10 years of age at the time of reconstruction, we asked what is (1) the limb length discrepancy at skeletal maturity and how was it managed; (2) the risk of amputation; (3) the risk of allograft removal; and (4) the risk of second surgery resulting from complications? METHODS: Between 1994 and 2006, we performed 22 bone allografts after bone sarcoma resections in children younger than 10 years of age. Of those, none were lost to followup before the minimum followup of 10 years was reached, and an additional six had died of disease (of whom three died since our last report on this group of patients), leaving 16 patients whom we studied here. Followup on these patients was at a mean of 13.5 years (range, 10-22 years). During the period in question, no other treatments (such as extendible prostheses, amputations, etc) were used. The mean age at the time of the original surgery was 7 years (range, 2-10 years), and the mean age of the 16 alive patients at last followup was 20 years (range, 15-28 years). This series included 10 boys and six girls with 14 osteosarcomas and two Ewing sarcomas. Ten reconstructions were performed with an intercalary allograft and six with an osteoarticular allograft. The growth plate was uninvolved in three patients, whereas in the remaining 13, the growth plate was included in the resection (seven intercalary and six osteoarticular allografts). Limb length discrepancy at skeletal maturity was measured with full-length standing radiographs, and data were collected by retrospective study of a longitudinally maintained institutional database. The risk of amputation, allograft removal, and secondary surgery resulting from a complication was calculated by a competing-risk analysis method. RESULTS: We observed no limb length discrepancy at skeletal maturity in the three patients with intercalary resections in whom we preserved the physes on both sides of the joint (two femurs and one tibia); however, one patient developed malalignment that was treated with corrective osteotomy of the tibia. The remaining 13 patients developed limb length discrepancy as a result of loss of one physis. Seven patients (four femurs, two tibias, and one humerus) developed shortening of ≤ 3 cm (mean, 2.4 cm; range, 1-3 cm) and no lengthening was performed. Six patients developed > 3 cm of limb discrepancy at skeletal maturity (all distal femoral reconstructions). In four patients this was treated with femoral lengthening, whereas two declined this procedure (each with 6 cm of shortening). In the four patients who had a lengthening procedure, one patient had a final discrepancy of 4 cm, whereas the other three had equal limb lengths at followup. The risk of amputation was 4% (95% confidence interval [CI], 0-15) and none occurred since our previous report. The risk of allograft removal was 15% (95% CI, 1-29) and none occurred since our previous report on this group of patients. The risk of other operations resulting from a complication was 38% (95% CI, 19-57). Eleven patients underwent a second operation resulting from a complication (three local recurrences, five fractures, one infection, one nonunion, and one tibial deformity), of which three were performed since our last report on this group of patients. CONCLUSIONS: Limb length inequalities and subsequent procedures to correct them were common in this small series of very young patients as were complications resulting in operative procedures, but overall most allografts remained in place at long-term followup. In skeletally immature children, bone allograft is one alternative among several that are available (such as rotationplasty and endoprosthesis), and future studies with long followup may be able to compare the available options with one another. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Osteosarcoma primario de mama en una paciente con antecedentes de tratamiento radioterápico loco-regional por carcinoma in situ mamario / Primary breast osteosarcoma in a patient with a history of locoregional radiotherapy treatment for breast carcinoma in situ

RESUMEN El cáncer de mama es el tumor más prevalente a nivel mundial entre las mujeres. A pesar de que la supervivencia global alcanza cifras cercanas al 90%, sigue suponiendo un importante problema sanitario y económico para la población. Los sarcomas primarios de mama suponen menos del 1% de estas neoplasias, pero sus tasas de recidiva y mortalidad son elevadas. Dado que no existen pruebas de imagen específicas para el diagnóstico, la confirmación de dicha entidad supone un reto a nivel histopatológico. El tratamiento del osteosarcoma de mama es principalmente quirúrgico, con la extirpación de la tumoración con márgenes adecuados, que será trascendental para el pronóstico de las pacientes. No se ha demostrado que sea necesaria una disección axilar, ni un tratamiento adyuvante estándar de quimioterapia ni radioterapia, salvo casos indicados. Presentamos el caso de una paciente postmenopaúsica que tras haber desarrollado un carcinoma ductal in situ de mama tratado de forma satisfactoria, desarrolla dos años posterior a la finalización del tratamiento radioterápico, y en la misma localización del tumor inicial, un osteosarcoma primario de mama de rápido crecimiento atribuible al efecto de la radioterapia administrada.

ABSTRACT Breast cancer is the most prevalent tumor worldwide among women. Despite the fact that overall survival reaches figures close to 90%, it continues to be an important health and economic problem for the population. Primary breast sarcomas account for less than 1% of these neoplasms but their rates of recurrence and mortality are high. Given that there are no specific imaging tests for diagnosis, confirmation of this entity is a challenge at the histopathological level. The treatment of the OSM is mainly surgical with the removal of the tumor with adequate margins, which will be transcendental for the prognosis of the patients. It has not been demonstrated that an axillary dissection is required, nor a standard adjuvant treatment of chemotherapy or radiotherapy, unless indicated. We present the case of a postmenopausal patient who, after having developed a ductal carcinoma in situ of the breast (DCIS) successfully treated, developed two years after the end of the radiotherapy treatment, and in the same location of the initial tumor, an osteosarcoma primary breast of rapid growth attributable to the effect of radiotherapy administered.