Epidemiology, Incidence, and Survival of Rhabdomyosarcoma Subtypes: SEER and ICES Database Analysis

Giant spindle cell rhabdomyosarcoma in an adult thorax: A case report

Spindle cell rhabdomyosarcoma (SCRM), a rare and distinct subtype of RM, predominantly affects children. While SCRM can manifest in the head and neck regions of adults, primary occurrences in the thorax are exceedingly uncommon. In the present study, a 24-year-old female patient was admitted to the Affiliated Hospital of Zunyi Medical University (Zunyi, China) with a 10-month history of dull pain in the right side of the chest. The patient had previously received treatment for right-sided tuberculous pleurisy at another hospital for 6 months, but the symptoms persisted, and the chest pain progressively worsened. A chest computed tomography scan now revealed a large mass in the right thorax. Pathological examination following surgical resection confirmed a diagnosis of SCRM. The patient did not undergo standardized postoperative chemoradiotherapy and the 5-year follow-up examination indicated tumor recurrence. Primary thoracic SCRM is a rare tumor that morphologically resembles other spindle cell tumors. Immunohistochemistry is crucial for an accurate diagnosis, and surgical resection remains the primary treatment approach. The clinicopathological features, molecular genetic characteristics and biological behavior of SCRM are largely unknown due to its rarity. Consequently, large-sample studies are essential to enhance the understanding of this tumor and advance precision medicine treatments.

The Other Site of Rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma (RMS) is a rare malignant soft tissue sarcoma (STS), accounting for almost 50% of pediatric STSs. Due to its heterogeneity, RMS presents challenges in diagnosis and treatment, with prognosis varying depending on multiple factors. Tumors localized in the other site (OTH)-including the paraspinal, perianal, thoracic, abdominal, pelvic, and perineal regions-are generally classified as unfavorable. This study assesses the clinical features and prognoses of RMS in OTH locations depending on its site of origin.

METHODS

An explorative analysis of RMS cases from the SEER 17 database 2000-2020 was conducted. Patients of all ages with histologically confirmed RMS as primary malignant disease classified under OTH, were included. OTH was categorized in four granular site classifications. Overall survival (OS) and disease-specific survival (DSS) were analyzed using Kaplan-Meier estimators. Factors independently influencing survival, including a site classification model presented in this study, were identified through Cox regression analysis.

RESULTS

Out of 4168 patients with RMS, 990 cases of RMS with the OTH site met the inclusion criteria. The median age was 16 years. The predominant histological subtypes were embryonal (33.0%) and alveolar (25.5%). Most tumors were ≥ 5 cm (median 9 cm) and located primarily in the pelvic region (41.5%). The 3-, 5-, and 10-year OS rates were 45.4% ± 3.332 (95% CI), 40.7 ± 3.332, and 38.6% ± 3.332, respectively, while DSS rates were 43.3% ± 3.136 (95% CI), 38.3% ± 3.136, and 35.1% ± 3.332. In the multivariate analysis age, histological type, site in a granular categorization, stage, regional lymph node examination, and regional lymph node involvement (pathologically proven) were independently associated with survival. Through both univariate and multivariate analyses, an OTH favorable group could be established. The OTH favorable group consists of the anal region, gallbladder and biliary tract, and breast.

CONCLUSION

RMS in OTH shows significant differences in prognosis, putting the current categorization as unfavorable into question and making a more detailed classification necessary. Furthermore, pathological regional lymph node assessment is specifically in the OTH localization recommended.

Impact of age on survival according to molecular tumor findings in children and adolescents with soft-tissue and bone sarcoma: The BIOSCA project

BACKGROUND

Adolescents (15-19 years) with sarcoma are known to have significantly worse survival than children (0-14 years). One possible reason may be that the adolescent sarcomas exhibit specific biological characteristics resulting in differences in clinical presentation and treatment resistance behaviors. The BIOSCA project aims to further explore these age-related differences in survival accounting for molecular tumor characteristic in children and adolescents with sarcoma.

METHODS

A retrospective national population-based observational study with documented somatic genetic analyses was conducted between 2011 and 2016 of all patients aged from 0 to 17 years with a diagnosis of sarcoma using the National Registry of Childhood Cancers Database.

RESULTS

A total of 1637 children (0-9years: 40%), preadolescents (10-14years: 35%) and adolescents (15-17 years: 25%) with a diagnosis of bone (N = 845) or soft-tissue (N = 792) sarcoma were included. Adolescents had significantly worse outcome for undifferentiated small round cell sarcoma (USRCS), alveolar rhabdomyosarcoma (ARMS), and epithelioid sarcoma. Five-year overall survivals were worse among CIC-rearranged USRCS cases (47% [95%CI:21-69]) as compared to other USRCS, and PAX3::FOXO1 ARMS patients (44% [95%CI:32-55]) as compared to other ARMS. Adjusting for stage and genomic-profiling status, adolescents with USRCS were 1.6-fold more likely to die than children (P = 0.05), while the difference in survival between age of ARMS patients was weaken. Indeed, the prevalence of PAX3::FOXO1 increased significantly with age.

CONCLUSION

Age was an independent prognostic factor of outcome only in patients with USRCS, while the association between age and survival of patients with ARMS could be partly explained by differences in prevalence of PAX3::FOXO1.

Isolated Pancreatic Metastasis in a Patient With Orbital Rhabdomyosarcoma: A Report of a Rare Case

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents and its occurrence in adults is extremely rare. There are three major subtypes of RMS of which alveolar RMS (ARMS) has the worst prognosis and tends to metastasize to unusual locations such as the pancreas. We present a case of a 19-year-old male with a rapidly enlarging right orbital mass, the imaging of which revealed it to be an infiltrative lesion with extension into the nasal cavity, ethmoid sinuses, and intracranial involvement. Histopathology confirmed the diagnosis of ARMS. A staging CT scan showed an enlarged and hypoenhancing pancreas; the histopathology test confirmed ARMS metastasis. It is important to consider pancreatic involvement in patients with ARMS, as it may be misinterpreted with other pathologies such as pancreatitis and pancreatic lymphoma. Metastasis to the pancreas can significantly alter the clinical approach and staging, underscoring the need for accurate diagnosis and staging in these patients.

Botryoid-type Embryonal Rhabdomyosarcoma: A Comprehensive Clinicopathologic and Molecular Appraisal With Cross-comparison to its Conventional-type Counterpart

Embryonal rhabdomyosarcoma (ERMS) is the most common subtype of RMS, occurring in soft tissue and visceral sites of young children, and is associated with favorable outcomes. A subset occurs in mucosal-lined luminal structures, displaying a unique grape-like growth termed as "botryoid-type." To further delineate the differences between conventional (cERMS) and botryoid-type (bERMS) RMS, we performed a comparative histologic review and comprehensive molecular profiling of 48 cases (25 bERMS and 23 cERMS). All tumors were subjected to a hybridization capture-based targeted matched tumor-normal DNA NGS assay. The mean age was 17 and 7 years for bERMS and cERMS, respectively. Most bERMS were female with a predilection for the gynecologic tract (75%), while cERMS had a slight male predominance and were preferentially located in abdominopelvic and paratesticular sites (30%, each). All bERMS exhibited an exophytic, bulbous architecture accompanied by a subepithelial "cambium layer." Distinctive germline alterations were detected, with DICER1 (18%) and FH (6%) mutations only in bERMS, and rare TP53, VHL, and APC mutations in cERMS. Similarly, contrasting somatic genomic landscapes were observed, with frequent DICER1 (52%, P**<0.0001) and TP53 (36%, P*<0.05) alterations exclusively in bERMS. Cartilaginous differentiation was only observed in DICER1-mutated bERMS. All patients had longitudinal follow-up. bERMS patients with somatic/germline DICER1 mutations showed significantly improved recurrence-free survival compared with that of DICER1-wild type patients (P*<0.05). Moreover, bERMS showed improved disease-specific survival compared with that of cERMS, with 8% versus 30% (P*<0.05) dead of disease, respectively. In summary, we compare the molecular underpinnings of the largest cohort of bERMS and cERMS with targeted DNA sequencing and long-term follow-up data. Our findings reveal divergent genomic topographies between the 2 groups, with bERMS showing unique germline and somatic abnormalities, including enrichment in DICER1 and TP53 alterations, and a trend towards improved survival.

Arsenic sulfide enhances radiosensitivity in rhabdomyosarcoma via activating NFATc3-RAG1 mediated DNA double strand break (DSB)

Rhabdomyosarcoma (RMS) represents one of the most lethal soft-tissue sarcomas in children. The toxic trace element arsenic has been reported to function as a radiosensitizer in sarcomas. To investigate the role of arsenic sulfide (As4S4) in enhancing radiation sensitization in RMS, this study was conducted to elucidate its underlying mechanism in radiotherapy. The combination of As4S4 and radiotherapy showed significant inhibition in RMS cells, as demonstrated by the cell counting kit-8 (CCK-8) assay and flow cytometry. Subsequently, we demonstrated for the first time that As4S4, as well as the knockdown of NFATc3 led to double-strand break (DSB) through increased expression of RAG1. In vivo experiment confirmed that co-treatment efficiently inhibited RMS growth. Furthermore, survival analysis of a clinical cohort consisting of 59 patients revealed a correlation between NFATc3 and RAG1 expression and overall survival (OS). Cox regression analysis also confirmed the independent prognostic significance of NFATc3 and RAG1.Taken together, As4S4 enhances radiosensitivity in RMS via activating NFATc3-RAG1 mediated DSB. NFATc3 and RAG1 are potential therapeutic targets. As4S4 will hopefully serve as a prospective radio-sensitizing agent for RMS.

Preclinical models for the study of pediatric solid tumors: focus on bone sarcomas

Sarcomas comprise between 10-15% of all pediatric malignancies. Osteosarcoma and Ewing sarcoma are the two most common pediatric bone tumors diagnosed in children and young adults. These tumors are commonly treated with surgery and/or radiation therapy and combination chemotherapy. However, there is a strong need for the development and utilization of targeted therapeutic methods to improve patient outcomes. Towards accomplishing this goal, pre-clinical models for these unique malignancies are of particular importance to design and test experimental therapeutic strategies prior to being introduced to patients due to their origination site and propensity to metastasize. Pre-clinical models offer several advantages for the study of pediatric sarcomas with unique benefits and shortcomings dependent on the type of model. This review addresses the types of pre-clinical models available for the study of pediatric solid tumors, with special attention to the bone sarcomas osteosarcoma and Ewing sarcoma.

Incidence, survival, and mortality of cancer in children and young adolescents in Belgium and the Netherlands in 2004-2015: A comparative population-based study

International comparisons of cancer surveillance measures may provide insight into inequalities in registration practices, etiological factors, and treatment strategies. This study aimed to compare incidence, survival, and mortality of cancer in children and young adolescents between Belgium and the Netherlands. All children (0-14 years) and young adolescents (15-17 years) diagnosed with cancer between 2004 and 2015 were selected from the population-based cancer registries of Belgium (N = 4739) and the Netherlands (N = 7322). Differences in incidence and mortality were expressed as standardized rate ratios (SRR; BE/NL). Five-year observed survival was calculated using the Kaplan-Meier method. During 2004-2015, the overall cancer incidence among children and young adolescents was similar in both countries. Incidence of neuroblastoma was significantly higher in Belgian children (2010-2015: SRR = 1.3, 95% CI 1.0-1.6). Five-year survival of all malignant cancers was comparable in 2010-2015, exceeding 80% in both age groups. Remarkable differences in survival existed in children for malignant central nervous system (CNS) tumors in 2004-2009 (BE = 62%, NL = 45%), for acute myeloid leukemia (BE = 68%, NL = 78%) and rhabdomyosarcomas (BE = 60%, NL = 79%) in 2010-2015, and for neuroblastoma in both periods (2004-2009: BE = 76%, NL = 64%; 2010-2015: BE = 82%, NL = 64%). Overall cancer mortality in children decreased by approximately 3 percent-points annually in both countries, but was slightly lower in Belgium in 2004-2009 (SRR = 0.9, 95% CI 0.7-1.0). Despite differences for specific cancer types, overall cancer incidence, survival, and mortality were comparable between Dutch and Belgian children and young adolescents in 2010-2015. Variability in screening, diagnosis, and registration practices probably explains the observed differences in incidence and survival of neuroblastoma and malignant CNS tumors.

Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine contrast-enhanced ultrasound guidelines: Multiparametric imaging and EUS-guided sampling in rare pancreatic tumors. Benign mesenchymal pancreatic tumors

The focus of the review is on primary benign mesenchymal pancreatic tumors and their imaging appearance. These tumors are extremely rare. Usually, they are not diagnosed until postoperative histology is available, and so even benign tumors have undergone extensive pancreatic resection. The very limited data on abdominal and EUS findings including contrast-enhanced techniques of these pancreatic lesions are summarized here. Case reports will be presented for some of these rare tumors with application of modern ultrasound and endosonographic techniques.

A systematic review of combined surgery and brachytherapy approaches for children and young people with relapsed and refractory rhabdomyosarcoma (Local-REFoRMS)

Approximately one third of children with rhabdomyosarcoma relapse or have refractory disease. Treatment approaches include a combination of systemic therapies and local therapies, directed at tumour site(s). This review was conducted to evaluate the effectiveness and safety of the combination of surgery and brachytherapy as local therapy for treating children and young people with relapsed/refractory rhabdomyosarcoma. This review identified studies based on a previous systematic review looking at the treatments for children and young people under 18 years old with relapsed/refractory rhabdomyosarcoma. Studies conducted after 2000 were included. Survival outcomes, relapse rates, adverse events and functional outcomes were extracted. From 16,965 records identified in the baseline systematic review, 205 included the words 'AMORE' or 'brachytherapy', and were screened for eligibility in this substudy. Thirteen studies met the inclusion criteria for Local-REFoRMS, including over 55 relapsed and refractory rhabdomyosarcoma patients. Most studies were retrospective cohort studies conducted within Europe. Most patients had embryonal disease within the head and neck or bladder/prostate regions, and received local therapy for first relapse. Approximately one quarter of patients relapsed following surgery and brachytherapy, with local relapses occurring more than metastatic relapse. Adverse events and functional outcomes were infrequently reported, but related to the site of surgery and brachytherapy. Study quality was limited by inconsistent reporting and potential selection bias. Outcomes following surgery and brachytherapy for a selected group of relapsed and refractory rhabdomyosarcoma show reasonable benefits, but reporting was often unclear and based on small sample sizes.

Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine contrast-enhanced ultrasonography guidelines: multiparametric imaging and EUS-guided sampling in rare pancreatic tumors. Mesenchymal pancreatic tumors of intermediate biological behaviour

The focus of the review is on mesenchymal pancreatic tumors with intermediate biological behavior and their imaging appearance. Similar to benign and malignant mesenchymal pancreatic tumors, these tumors are extremely rare. The diagnosis is often confirmed only by postoperative histology. The very limited data on abdominal ultrasound and EUS findings including contrast-enhanced techniques of these pancreatic lesions are summarized here.

Molecular Imaging with PET-CT and PET-MRI in Pediatric Musculoskeletal Diseases

Molecular imaging has emerged as an integral part of oncologic imaging. Given the physiologic changes that precede anatomic changes, molecular imaging can enable early detection of disease and monitoring of response. [18F] Fluorodeoxyglucose (FDG) Positron emission tomography (PET) is the predominant molecular imaging modality used in oncologic assessment and can be performed using PET/CT or PET/MR. In pediatric patients, PET/MRI imaging is generally preferred due to low radiation exposure and PET/MRI is particularly advantageous for imaging musculoskeletal (MSK) diseases, as MRI provides superior characterization of tissue changes as compared to CT. In this article, we provide an overview of the typical role of PET CT/MRI in assessment of some common pediatric malignancies and benign MSK diseases with case examples. We also discuss the relative advantages of PET/MRI compared to PET/CT, and review published data with a primary focus on the use of PET/MR.

68 Ga-Pentixafor PET/CT for in-vivo mapping of CXCR4 receptors as potential radiotheranostic targets in soft tissue and bone sarcoma: preliminary results

OBJECTIVE

To evaluate the diagnostic utility of 68 Ga-Pentixafor PET/CT for in vivo imaging of CXCR4 receptors in soft tissue/bone sarcoma.

METHODS

Ten (7M: 3F; mean age = 24.7 ± 14.2 years) consecutive patients with clinical and radiological evidence of bone/soft tissue sarcoma were recruited prospectively whole body 68 Ga-Pentixafor PET/CT imaging was performed at 60-min after tracer administration. After performing standard CT, PET acquisition from head to toe was done (3 min/bed position) in a caudocranial direction. PET/CT data was reconstructed and SUV max , SUV mean values, target-to-background ratio (TBR) and active tumor volume (cc) were computed for the tracer avid lesions. Histopathological and IHC analysis was performed on the surgically excised primary tumors. CXCR4 receptors' intensity was evaluated by visual scoring.

RESULTS

The mean SUV max and SUV mean values in the primary tumors were 4.80 ± 1.0 (3.9-7.7) and 2.40 ± 0.60 (0.9-4.0). The mean TBR and tumor volume (cc) were 1.84 ± 1.3 and 312.2 ± 285. Diagnosis of osteosarcoma in 7, chondrosarcoma, leiomyosarcoma and synovial sarcoma in 1 patient each was confirmed on HP analysis. Distant metastatic lesions were seen in 3/10 patients. Nuclear CXCR4 receptors' positivity was seen in 5, cytoplasmic in 4 and both pattern seen in 1 patient. The mean CXCR4 receptors' intensity was found to be 7.6 ± 2. The highest SUV max value of 7.7 was observed in the patient having both cytoplasmic and nuclear CXCR4 expression. SUV max was found to be poorly correlated ( r  = 0.441) with CXCR4 expression.

CONCLUSION

68 Ga-Pentixafor PET/CT detects CXCR4 receptors over-expressed in sarcoma, its radio-theranostics potential needs detailed evaluation.

Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine guidelines: Rare pancreatic tumors, ultrasound and contrast-enhanced ultrasound features-Malignant mesenchymal tumors

Rare malignant mesenchymal pancreatic tumors are systematized and reported in this review. The focus is on the appearance on imaging. The present overview summarizes the data and shows that not every pancreatic tumor corresponds to the most common entities of ductal adenocarcinoma or neuroendocrine tumor.

Analyzing socio-environmental determinants of bone and soft tissue cancer in Indonesia

BACKGROUND

This study is designed to explore the potential impact of individual and environmental residential factors as risk determinants for bone and soft tissue cancers, with a particular focus on the Indonesian context. While it is widely recognized that our living environment can significantly influence cancer development, there has been a notable scarcity of research into how specific living environment characteristics relate to the risk of bone and soft tissue cancers.

METHODS

In a cross-sectional study, we analyzed the medical records of oncology patients treated at Prof. Suharso National Referral Orthopedic Hospital. The study aimed to assess tumor malignancy levels and explore the relationships with socio-environmental variables, including gender, distance from the sea, sunrise time, altitude, and population density. Data were gathered in 2020 from diverse sources, including medical records, Google Earth, and local statistical centers. The statistical analyses employed Chi-square and logistic regression techniques with the support of Predictive Analytics SoftWare (PASW) Statistics 18.

RESULTS

Both bivariate and multivariate analyses revealed two significant factors associated with the occurrence of bone and soft tissue cancer. Age exhibited a statistically significant influence (OR of 5.345 and a p-value of 0.000 < 0.05), indicating a robust connection between cancer development and age. Additionally, residing within a distance of less than 14 km from the sea significantly affected the likelihood of bone and soft tissue cancers OR 5.604 and p-value (0.001 < 0.05).

CONCLUSIONS

The study underscores the strong association between age and the development of these cancers, emphasizing the need for heightened vigilance and screening measures in older populations. Moreover, proximity to the sea emerges as another noteworthy factor influencing cancer risk, suggesting potential environmental factors at play. These results highlight the multifaceted nature of cancer causation and underscore the importance of considering socio-environmental variables when assessing cancer risk factors. Such insights can inform more targeted prevention and early detection strategies, ultimately contributing to improved cancer management and patient outcomes.

Local Treatment of Children Suffering From Parameningeal Rhabdomyosarcoma: A Retrospective Single-Center Study From China

BACKGROUND

Treatment for parameningeal rhabdomyosarcoma (PM-RMS) has been a challenge since local control is difficult. The goal of this study was to analyse the impact of different local treatment approaches on childhood PM-RMS patients and help dispel the doubt that whether secondary radical surgery (SRS) should be encouraged in the management of PM-RMS.

METHODS

A total of 17 children with PM-RMS who received unified systemic chemotherapy and individualized local therapy such as radiotherapy (RT) and/or SRS were included in this retrospective study. The overall survival (OS) and event free survival (EFS) were compared between groups adopting different local strategies.

RESULTS

The 3-year OS and EFS of our PM-RMS patients was 75.5% and 56.5% respectively. The OS and EFS of patients who received SRS were both significantly lower than that of the non-SRS group (3-year OS: 50.0% vs 90.0%, P = .031; 3-year EFS: 33.3% vs 60.6%, P = .020). The OS and EFS of the patients who received RT was higher than that of the patients of the non-RT group (3-year OS: 85.6% vs 0%, P = .001; 3-year EFS: 64.0% vs 0%, P = .011).

CONCLUSION

This study illustrates that SRS was associated with poor prognosis of PM-RMS and should not be routinely performed. Optimized RT strategies along with more intensive chemotherapy may be alternative options to improve the survival of patients with PM-RMS. Multi-center, large sample and prospective studies are needed to further validate these findings.

Inhibition of NAD+-Dependent Metabolic Processes Induces Cellular Necrosis and Tumor Regression in Rhabdomyosarcoma Models

PURPOSE

Deregulated metabolism in cancer cells represents a vulnerability that may be therapeutically exploited to benefit patients. One such target is nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD+ salvage pathway. NAMPT is necessary for efficient NAD+ production and may be exploited in cells with increased metabolic demands. We have identified NAMPT as a dependency in rhabdomyosarcoma (RMS), a malignancy for which novel therapies are critically needed. Here we describe the effect of NAMPT inhibition on RMS proliferation and metabolism in vitro and in vivo.

EXPERIMENTAL DESIGN

Assays of proliferation and cell death were used to determine the effects of pharmacologic NAMPT inhibition in a panel of ten molecularly diverse RMS cell lines. Mechanism of the clinical NAMPTi OT-82 was determined using measures of NAD+ and downstream NAD+-dependent functions, including energy metabolism. We used orthotopic xenograft models to examine tolerability, efficacy, and drug mechanism in vivo.

RESULTS

Across all ten RMS cell lines, OT-82 depleted NAD+ and inhibited cell growth at concentrations ≤1 nmol/L. Significant impairment of glycolysis was a universal finding, with some cell lines also exhibiting diminished oxidative phosphorylation. Most cell lines experienced profound depletion of ATP with subsequent irreversible necrotic cell death. Importantly, loss of NAD and glycolytic activity were confirmed in orthotopic in vivo models, which exhibited complete tumor regressions with OT-82 treatment delivered on the clinical schedule.

CONCLUSIONS

RMS is highly vulnerable to NAMPT inhibition. These findings underscore the need for further clinical study of this class of agents for this malignancy.

Small bowel metastasis from embryonal rhabdomyosarcoma of the extremity- a case report

Rhabdomyosarcoma is the most common soft tissue tumour in children and adolescents, but extremely rare in adults with comparatively worse outcomes. Metastatic disease is not uncommon, but intra-abdominal metastases are exceedingly rare. We report an unusual case of ileal metastases from an upper extremity rhabdomyosarcoma in a 17-year-old male who presented with abdominal pain during a routine follow-up visit. Laparotomy and ileocecectomy for a perforated ileal mass confirmed metastatic embryonal rhabdomyosarcoma with 1 out of 14 positive lymph node metastases. This case demonstrates that, although rare, intra-abdominal metastases should be considered when patients with a rhabdomyosarcoma present with abdominal complaints.

Complete loss of TP53 and RB1 is associated with complex genome and low immune infiltrate in pleomorphic rhabdomyosarcoma

Rhabdomyosarcoma accounts for roughly 1% of adult sarcomas, with pleomorphic rhabdomyosarcoma (PRMS) as the most common subtype. Survival outcomes remain poor for patients with PRMS, and little is known about the molecular drivers of this disease. To better characterize PRMS, we performed a broad array of genomic and immunostaining analyses on 25 patient samples. In terms of gene expression and methylation, PRMS clustered more closely with other complex karyotype sarcomas than with pediatric alveolar and embryonal rhabdomyosarcoma. Immune infiltrate levels in PRMS were among the highest observed in multiple sarcoma types and contrasted with low levels in other rhabdomyosarcoma subtypes. Lower immune infiltrate was associated with complete loss of both TP53 and RB1. This comprehensive characterization of the genetic, epigenetic, and immune landscape of PRMS provides a roadmap for improved prognostications and therapeutic exploration.

SIX1 as a Novel Immunohistochemical Marker in the Differential Diagnosis of Rhabdomyosarcoma

Background: Differential diagnosis of rhabdomyosarcoma (RMS) is challenging. Sineoculis homeobox homolog 1 (SIX1) is an oncogene involved in skeletal muscle differentiation. We compared protein expression patterns of SIX1 in RMS and its most common differential diagnoses. Methods: SIX1 immunohistochemistry in 36 RMS and in 33 tumors from seven differential diagnostic subtypes were evaluated. The fraction of SIX1 positive tumor cells was scored by three independent observers. Results: A majority (75%) of the evaluated RMS expressed SIX1 in at least 50% of tumor cells and all except one RMS had more than 25% positive tumor cells. Neuroblastoma had less than 1% SIX1 positive tumor cells. Gonadoblastoma, malignant rhabdoid tumor, and Ewing sarcoma had 10% or less positive tumor cells. Pleuropulmonary blastoma exhibited 26-50% positive tumor cells and synovial sarcoma >50% positive cells. Conclusion: SIX1 immunohistochemistry is positive in most RMS, and occasionally in some tumors within the differential diagnoses of RMS.

A dysfunctional miR-1-TRPS1-MYOG axis drives ERMS by suppressing terminal myogenic differentiation

Rhabdomyosarcoma is the most common pediatric soft tissue tumor, comprising two major subtypes: the PAX3/7-FOXO1 fusion-negative embryonal and the PAX3/7-FOXO1 fusion-positive alveolar subtype. Here, we demonstrate that the expression levels of the transcriptional repressor TRPS1 are specifically enhanced in the embryonal subtype, resulting in impaired terminal myogenic differentiation and tumor growth. During normal myogenesis, expression levels of TRPS1 have to decrease to allow myogenic progression, as demonstrated by overexpression of TRPS1 in myoblasts impairing myotube formation. Consequentially, myogenic differentiation in embryonal rhabdomyosarcoma in vitro as well as in vivo can be achieved by reducing TRPS1 levels. Furthermore, we show that TRPS1 levels in RD cells, the bona fide model cell line for embryonal rhabdomyosarcoma, are regulated by miR-1 and that TRPS1 and MYOD1 share common genomic binding sites. The myogenin (MYOG) promoter is one of the critical targets of TRPS1 and MYOD1; we demonstrate that TRPS1 restricts MYOG expression and thereby inhibits terminal myogenic differentiation. Therefore, reduction of TRPS1 levels in embryonal rhabdomyosarcoma might be a therapeutic approach to drive embryonal rhabdomyosarcoma cells into myogenic differentiation, thereby generating postmitotic myotubes.

Fine-Needle Aspiration of Sarcomas Metastatic to Lymph Nodes: A Cytomorphologic Study over a 10-Year Period

INTRODUCTION

Metastasis of sarcomas to lymph nodes is an uncommon event in its natural history. We aimed to present our experience with fine-needle aspiration (FNA) of metastatic sarcomas to lymph nodes over a 10-year period.

MATERIAL AND METHODS

The cytopathology archives were searched for FNA of lymph nodes involved by metastatic sarcomas. Available clinicopathologic data were recorded. All slides were retrieved and reviewed.

RESULTS

Thirty-three lymph nodes, from 30 patients, with metastatic soft tissue sarcomas were identified. The lymph node metastases occurred in 16 males and 14 females (median age, 56 years). The size of the lymph nodes ranged from 1.2 to 7.5 cm (median size, 2.9 cm). The inguinal lymph nodes were the most commonly involved nodes, followed by thoracic and cervical neck nodes. The most common metastatic soft tissue sarcoma encountered was Kaposi sarcoma (n = 7, 23.3%), followed by angiosarcoma (n = 6, 20%) and rhabdomyosarcoma (n = 6, 20%). The most common site of primary soft tissue sarcoma was the head and neck (n = 8, 26.6%), followed by lower extremity (n = 7, 23.3%). The initial diagnosis of sarcoma was established in 6 cases. Seventen patients had metachronous involvement of lymph nodes, while the remaining patients had synchronous involvement. Seventen patients died of disease, and the survival after lymph node metastasis ranged from 1 to 43 months.

CONCLUSION

FNA is an accurate and effective method in the diagnosis of metastatic sarcoma to lymph nodes. Knowledge of clinical findings and primary tumor diagnosis along with careful assessment of the cytomorphology is extremely helpful for an accurate diagnosis of metastases.

Survival Outcomes of Ewing Sarcoma and Rhabdomyosarcoma by High- versus Low-Volume Cancer Centres in British Columbia, Canada

Due to the rarity and complexity of treatment for Ewing sarcoma and rhabdomyosarcoma, studies demonstrate improved patient outcomes when managed by a multidisciplinary team at high-volume centres (HVCs). Our study explores the difference in outcomes of Ewing sarcoma and rhabdomyosarcoma patients based on the centre of initial consultation in British Columbia, Canada. This retrospective study assessed adults diagnosed with Ewing sarcoma and rhabdomyosarcoma between 1 January 2000 and 31 December 2020 undergoing curative intent therapy in one of five cancer centres across the province. Seventy-seven patients were included, 46 seen at HVCs and 31 at low-volume centres (LVCs). Patients at HVCs were younger (32.1 vs. 40.8 years, p = 0.020) and more likely to receive curative intent radiation (88% vs. 67%, p = 0.047). The time from diagnosis to first chemotherapy was 24 days shorter at HVCs (26 vs. 50 days, p = 0.120). There was no significant difference in overall survival by treatment centre (HR 0.850, 95% CI 0.448-1.614). Variations in care exist amongst patients treated at HVCs vs. LVCs, which may reflect differences in access to resources, clinical specialists, and varying practice patterns across centres. This study can be used to inform decisions regarding triaging and centralization of Ewing sarcoma and rhabdomyosarcoma patient treatment.

Impact of race and ethnicity on presentation and outcomes of patients treated on rhabdomyosarcoma clinical trials: A report from the Children's Oncology Group

BACKGROUND

Racial and ethnic disparities have been demonstrated in pediatric and adult cancers. However, there is no consensus on whether such disparities exist in the presentation, treatment, and outcome of patients with rhabdomyosarcoma (RMS).

METHODS

Patient information from the seven most recent RMS clinical trials was obtained from the Children's Oncology Group (COG). Chi-squared analyses were used to compare patient, tumor, and treatment characteristics across racial and ethnic groups. Pairwise analyses comparing Non-Hispanic Black (NHB) versus Non-Hispanic White (NHW) racial groups and Hispanic versus NHW ethnic groups were conducted for significant characteristics. Kaplan-Meier method and Wilcoxon signed-rank tests were performed to analyze outcomes.

RESULTS

In the overall cohort (n = 2157), patients' self-identified race/ethnicity was: 0.4% American Indian/Alaska Native, 2.6% Asian, 12.6% Hispanic, 0.2% Native American/other Pacific Islander, 12.8% NHB, 61.9% NHW, and 9.6% unknown. Six characteristics differed by race/ethnicity: age, histology, IRS group, invasiveness, metastatic disease, and FOXO1 fusion partner. Five were significant in pairwise comparisons: NHB patients were more likely to present at age ≥ 10 years and with invasive tumors than NHW patients; Hispanic patients were more likely to present with alveolar histology, metastatic disease, and IRS group IV disease than NHW patients. No differences were found in event free or overall survival of the entire cohort, in risk group-based subset analyses, or among patients with high-risk characteristics significant on pairwise analysis.

CONCLUSIONS

While NHB and Hispanic patients enrolled in COG trials presented with higher risk features than NHW patients, there were no outcome differences by racial or ethnic group.

The MYC-YBX1 Circuit in Maintaining Stem-like Vincristine-Resistant Cells in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is a pediatric soft tissue sarcoma that causes significant devastation, with no effective therapy for relapsed disease. The mechanisms behind treatment failures are poorly understood. Our study showed that treatment of RMS cells with vincristine led to an increase in CD133-positive stem-like resistant cells. Single cell RNAseq analysis revealed that MYC and YBX1 were among the top-scoring transcription factors in CD133-high expressing cells. Targeting MYC and YBX1 using CRISPR/Cas9 reduced stem-like characteristics and viability of the vincristine-resistant cells. MYC and YBX1 showed mutual regulation, with MYC binding to the YBX1 promoter and YBX1 binding to MYC mRNA. The MYC inhibitor MYC361i synergized with vincristine to reduce tumor growth and stem-like cells in a zebrafish model of RMS. MYC and YBX expression showed a positive correlation in RMS patients, and high MYC expression correlated with poor survival. Targeting the MYC-YBX1 axis holds promise for improving survival in RMS patients.

Detection of circulating tumor-derived material in peripheral blood of pediatric sarcoma patients: A systematic review

BACKGROUND

Detection of circulating tumor-derived material (cTM) in the peripheral blood (PB) of cancer patients has been shown to be useful in early diagnosis, prediction of prognosis, and disease monitoring. However, it has not yet been thoroughly evaluated for pediatric sarcoma patients.

METHODS

We searched the PubMed and EMBASE databases for studies reporting the detection of circulating tumor cells, circulating tumor DNA, and circulating RNA in PB of pediatric sarcoma patients. Data on performance in identifying cTM and its applicability in diagnosis, and evaluation of tumor characteristics, prognostic factors, and treatment response was extracted from publications.

RESULTS

A total of 79 studies were assigned for the present systematic review, including detection of circulating tumor cells (116 patients), circulating tumor DNA (716 patients), and circulating RNA (2887 patients). Circulating tumor cells were detected in 76% of patients. Circulating DNA was detected in 63% by targeted NGS, 66% by shallow WGS, and 79% by digital droplet PCR. Circulating RNA was detected in 37% of patients.

CONCLUSION

Of the cTM from Ewing's sarcoma and rhabdomyosarcoma ctDNA proved to be the best target for clinical application including diagnosis, tumor characterization, prognosis, and monitoring of disease progression and treatment response. For osteosarcoma the most promising targets are copy number alterations or patient specific micro RNAs, however, further investigations are needed to obtain consensus on clinical utility.

Evaluation of the Immunological Response of Childhood Cancer Patients Treated with a Personalized Peptide Vaccine for Refractory Soft Tissue Tumor: A Four-Case Series

This case series aimed to evaluate the peptide-specific immunoglobulin G (IgG) response, clinical effectiveness, and the safety of a personalized peptide vaccine (PPV) in four children with refractory solid cancer. Although the pre-vaccination IgG responses were suppressed, IgG levels against the vaccinated peptides after 12 vaccinations were increased in all three cases who received at least 12 vaccinations. Vaccination-related adverse effects were grade 1 injection-site local skin lesions. One patient, whose diagnosis was relapsed rhabdomyosarcoma, remains in sustained remission after 37 months. Although the pre-vaccination immune response in this patient was low, IgG levels against 2 of the 4 peptide vaccines were increased after the sixth vaccination, followed by a strong increase at the eighteenth vaccination against all 4 peptides, with a >100-fold increase vs. 2 peptides. The remaining three patients exhibited progressive disease and eventually died of their original cancer. The results of the current case series suggest that in cases of childhood solid tumors, when the tumor is controlled at the time of entry PPV may have some consolidation effect. Therefore, PPV could be a new immunotherapy modality for refractory childhood solid tumors.

Cancer Stem Cells in Sarcomas: In Vitro Isolation and Role as Prognostic Markers: A Systematic Review

Sarcomas are a diverse group of neoplasms with an incidence rate of 15% of childhood cancers. They exhibit a high tendency to develop early metastases and are often resistant to available treatments, resulting in poor prognosis and survival. In this context, cancer stem cells (CSCs) have been implicated in recurrence, metastasis, and drug resistance, making the search for diagnostic and prognostic biomarkers of the disease crucial. The objective of this systematic review was to analyze the expression of CSC biomarkers both after isolation from in vitro cell lines and from the complete cell population of patient tumor samples. A total of 228 publications from January 2011 to June 2021 was retrieved from different databases, of which 35 articles were included for analysis. The studies demonstrated significant heterogeneity in both the markers detected and the CSC isolation techniques used. ALDH was identified as a common marker in various types of sarcomas. In conclusion, the identification of CSC markers in sarcomas may facilitate the development of personalized medicine and improve treatment outcomes.

Feasibility and Toxicity of Interval-Compressed Chemotherapy in Asian Children and Young Adults with Sarcoma

Twelve Asian patients with sarcoma received interval-compressed (ic-) chemotherapy scheduled every 14 days with a regimen of vincristine (2 mg/m²), doxorubicin (75 mg/m²), and cyclophosphamide (1200-2200 mg/m²) (VDC) alternating with a regimen of ifosfamide (9000 mg/m²) and etoposide (500 mg/m²) (IE), with filgrastim (5-10 mcg/kg/day) between cycles. Carboplatin (800 mg/m²) was added for CIC-rearranged sarcoma. The patients were treated with 129 cycles of ic-VDC/IE with a median interval of 19 days (interquartile range [IQR], 15-24 days. Median nadirs (IQR) were neutrophil count, 134 (30-396) × 10⁶/L at day 11 (10-12), recovery by day 15 (14-17) and platelet count, 35 (23-83) × 10⁹/L at day 11 (10-13), recovery by day 17 (14-21). Fever and bacteremia were observed in 36% and 8% of cycles, respectively. The diagnoses were Ewing sarcoma (6), rhabdomyosarcoma (3), myoepithelial carcinoma (1), malignant peripheral nerve sheath tumor (1), and CIC-DUX4 Sarcoma (1). Seven of the nine patients with measurable tumors responded (one CR and six PR). Interval-compressed chemotherapy is feasible in the treatment of Asian children and young adults with sarcomas.

Rhabdomyosarcoma mimicking lymphoma

Background

Rhabdomyosarcoma (RMS) is a malignant soft tissue tumor that accounts for approximately one-half of soft tissue sarcomas in childhood age groups. Metastatic RMS is a rare condition that occurs in less than 25% of patients at diagnosis and can have variable clinical presentations.

Case presentation

Here we report a 17-year-old boy with history of weight loss, fever and generalized bone pain admitted for severe hypercalcemia. The definite diagnosis of RMS was performed with immune-phenotyping of the metastatic lymph-node biopsy. The primary tumor site was not found. His bone scan showed diffuse bone metastasis and significant soft tissue technetium uptake due to extra-osseous calcification.

Conclusion

Metastatic RMS can mimic lymphoproliferative disorders at presentation. Clinicians must be aware of this diagnosis especially in young adults.

Naturally occurring canine sarcomas: Bridging the gap from mouse models to human patients through cross-disciplinary research partnerships

Fueled by support from the National Cancer Institute's "Cancer Moonshot" program, the past few years have witnessed a renewed interest in the canine spontaneous cancer model as an invaluable resource in translational oncology research. Increasingly, there is awareness that pet dogs with cancer provide an accessible bridge to improving the efficiency of cancer drug discovery and clinical therapeutic development. Canine tumors share many biological, genetic, and histologic features with their human tumor counterparts, and most importantly, retain the complexities of naturally occurring drug resistance, metastasis, and tumor-host immune interactions, all of which are difficult to recapitulate in induced or genetically engineered murine tumor models. The utility of canine models has been particularly apparent in sarcoma research, where the increased incidence of sarcomas in dogs as compared to people has facilitated comparative research resulting in treatment advances benefitting both species. Although there is an increasing awareness of the advantages in using spontaneous canine sarcoma models for research, these models remain underutilized, in part due to a lack of more permanent institutional and cross-institutional infrastructure to support partnerships between veterinary and human clinician-scientists. In this review, we provide an updated overview of historical and current applications of spontaneously occurring canine tumor models in sarcoma research, with particular attention to knowledge gaps, limitations, and growth opportunities within these applications. Furthermore, we propose considerations for working within existing veterinary translational and comparative oncology research infrastructures to maximize the benefit of partnerships between veterinary and human biomedical researchers within and across institutions to improve the utility and application of spontaneous canine sarcomas in translational oncology research.

Is the Number of National Database Research Studies in Musculoskeletal Sarcoma Increasing, and Are These Studies Reliable?

BACKGROUND

Large national databases have become a common source of information on patterns of cancer care in the United States, particularly for low-incidence diseases such as sarcoma. Although aggregating information from many hospitals can achieve statistical power, this may come at a cost when complex variables must be abstracted from the medical record. There is a current lack of understanding of the frequency of use of the Surveillance, Epidemiology, and End Results (SEER) database and the National Cancer Database (NCDB) over the last two decades in musculoskeletal sarcoma research and whether their use tends to produce papers with conflicting findings.

QUESTIONS/PURPOSES

(1) Is the number of published studies using the SEER and NCDB databases in musculoskeletal sarcoma research increasing over time? (2) What are the author, journal, and content characteristics of these studies? (3) Do studies using the SEER and the NCDB databases for similar diagnoses and study questions report concordant or discordant key findings? (4) Are the administrative data reported by our institution to the SEER and the NCDB databases concordant with the data in our longitudinally maintained, physician-run orthopaedic oncology dataset?

METHODS

To answer our first three questions, PubMed was searched from 2001 through 2020 for all studies using the SEER or the NCDB databases to evaluate sarcoma. Studies were excluded from the review if they did not use these databases or studied anatomic locations other than the extremities, nonretroperitoneal pelvis, trunk, chest wall, or spine. To answer our first question, the number of SEER and NCDB studies were counted by year. The publication rate over the 20-year span was assessed with simple linear regression modeling. The difference in the mean number of studies between 5-year intervals (2001-2005, 2006-2010, 2011-2015, 2016-2020) was also assessed with Student t-tests. To answer our second question, we recorded and summarized descriptive data regarding author, journal, and content for these studies. To answer our third question, we grouped all studies by diagnosis, and then identified studies that shared the same diagnosis and a similar major study question with at least one other study. We then categorized study questions (and their associated studies) as having concordant findings, discordant findings, or mixed findings. Proportions of studies with concordant, discordant, or mixed findings were compared. To answer our fourth question, a coding audit was performed assessing the concordance of nationally reported administrative data from our institution with data from our longitudinally maintained, physician-run orthopaedic oncology dataset in a series of patients during the past 3 years. Our orthopaedic oncology dataset is maintained on a weekly basis by the senior author who manually records data directly from the medical record and sarcoma tumor board consensus notes; this dataset served as the gold standard for data comparison. We compared date of birth, surgery date, margin status, tumor size, clinical stage, and adjuvant treatment.

RESULTS

The number of musculoskeletal sarcoma studies using the SEER and the NCDB databases has steadily increased over time in a linear regression model (β = 2.51; p < 0.001). The mean number of studies per year more than tripled during 2016-2020 compared with 2011-2015 (39 versus 13 studies; mean difference 26 ± 11; p = 0.03). Of the 299 studies in total, 56% (168 of 299) have been published since 2018. Nineteen institutions published more than five studies, and the most studies from one institution was 13. Orthopaedic surgeons authored 35% (104 of 299) of studies, and medical oncology journals published 44% (130 of 299). Of the 94 studies (31% of total [94 of 299]) that shared a major study question with at least one other study, 35% (33 of 94) reported discordant key findings, 29% (27 of 94) reported mixed key findings, and 44% (41 of 94) reported concordant key findings. Both concordant and discordant groups included papers on prognostic factors, demographic factors, and treatment strategies. When we compared nationally reported administrative data from our institution with our orthopaedic oncology dataset, we found clinically important discrepancies in adjuvant treatment (19% [15 of 77]), tumor size (21% [16 of 77]), surgery date (23% [18 of 77]), surgical margins (38% [29 of 77]), and clinical stage (77% [59 of 77]).

CONCLUSION

Appropriate use of databases in musculoskeletal cancer research is essential to promote clear interpretation of findings, as almost two-thirds of studies we evaluated that asked similar study questions produced discordant or mixed key findings. Readers should be mindful of the differences in what each database seeks to convey because asking the same questions of different databases may result in different answers depending on what information each database captures. Likewise, differences in how studies determine which patients to include or exclude, how they handle missing data, and what they choose to emphasize may result in different messages getting drawn from large-database studies. Still, given the rarity and heterogeneity of sarcomas, these databases remain particularly useful in musculoskeletal cancer research for nationwide incidence estimations, risk factor/prognostic factor assessment, patient demographic and hospital-level variable assessment, patterns of care over time, and hypothesis generation for future prospective studies.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Resistance and endurance exercise training improves muscle mass and the inflammatory/fibrotic transcriptome in a rhabdomyosarcoma model

BACKGROUND

Rhabdomyosarcoma (RMS) is an aggressive soft tissue sarcoma that most often develops in children. Chemoradiation therapy is a standard treatment modality; however, the detrimental long-term skeletal muscle consequences of this therapy in juvenile cancer survivors include muscle atrophy and fibrosis resulting in decreased physical performance. Using a novel model of murine resistance and endurance exercise training, we investigate its role in preventing the long-term effects of juvenile RMS plus therapy.

METHODS

Four-week-old male (n = 10) and female (n = 10) C57Bl/6J mice were injected with M3-9-M RMS cell into the left gastrocnemius with the right limb serving as an internal control (CON). Mice received a systemic vincristine injection and then five doses of 4.8 Gy of gamma radiation localized to the left hindlimb (RMS + Tx). Mice were then randomly divided into either sedentary (SED) or resistance and endurance exercise training (RET) groups. Changes in exercise performance, body composition, myocellular adaptations and the inflammatory/fibrotic transcriptome were assessed.

RESULTS

RET improved endurance performance (P < 0.0001) and body composition (P = 0.0004) compared to SED. RMS + Tx resulted in significantly lower muscle weight (P = 0.015) and significantly smaller myofibre cross-sectional area (CSA) (P = 0.014). Conversely, RET resulted in significantly higher muscle weight (P = 0.030) and significantly larger Type IIA (P = 0.014) and IIB (P = 0.015) fibre CSA. RMS + Tx resulted in significantly more muscle fibrosis (P = 0.028), which was not prevented by RET. RMS + Tx resulted in significantly fewer mononuclear cells (P < 0.05) and muscle satellite (stem) cells (MuSCs) (P < 0.05) and significantly more immune cells (P < 0.05) than CON. RET resulted in significantly more fibro-adipogenic progenitors (P < 0.05), a trend for more MuSCs (P = 0.076) than SED and significantly more endothelial cells specifically in the RMS + Tx limb. Transcriptomic changes revealed significantly higher expression of inflammatory and fibrotic genes in RMS + Tx, which was prevented by RET. In the RMS + Tx model, RET also significantly altered expression of genes involved in extracellular matrix turnover.

CONCLUSIONS

Our study suggests that RET preserves muscle mass and performance in a model of juvenile RMS survivorship while partially restoring cellular dynamics and the inflammatory and fibrotic transcriptome.

Practice Pattern Variability in the Management of Regional Lymph Node Metastasis in Extremity and Trunk Soft Tissue Sarcoma: A Survey of the Society of Surgical Oncology and Musculoskeletal Tumor Society Membership

BACKGROUND

Regional lymph node metastasis in extremity and trunk soft tissue sarcoma (ETSTS) is rare with no standardized management. We sought to determine management patterns for regional lymph node metastasis in ETSTS.

METHODS

A survey regarding the management of ETSTS lymph node metastasis was distributed to the membership of the Musculoskeletal Tumor Society (MSTS) and the Society of Surgical Oncology (SSO) in January 2022. The survey queried the type of training (surgical oncology, orthopedic oncology), details of their practice setting, and management decisions of hypothetical ETSTS scenarios that involved potential or confirmed lymph node metastasis.

RESULTS

The survey was distributed to 349 MSTS members (open rate of 63%, completion rate 21%) and 3026 SSO members (open rate of 55%, completion rate 4.7%) and was completed by 214 respondents, of whom 73 (34.1%) and 141 (65.9%) were orthopedic oncology and surgical oncology fellowship-trained, respectively. The majority of respondents practiced in an academic setting (n = 171, 79.9%) and treat >10 extremity sarcoma cases annually (n = 138, 62.2%). In scenarios with confirmed nodal disease for clear cell and epithelioid sarcoma, surgical oncologists were inclined to perform lymphadenectomy, while orthopedic oncologists were inclined to offer targeted lymph node excision with adjuvant radiation (p < 0.001). There was heterogeneity of responses regarding the management of nodal disease regardless of training background.

CONCLUSION

Self-reported management of nodal disease in ETSTS was variable among respondent groups with differences and similarities based on training background. These data highlight the variability of practice for nodal disease management and the need for consensus-based guidelines.

About a Large Botryoid Rhabdomyosarcoma in a Little Girl: Management Difficulties and Literature Review

Background

Rhabdomyosarcoma (RMS) is a rare high-grade malignant tumor and the most common soft-tissue sarcoma, which occurs in young girl over 5 years old. Multimodality treatment associating with surgery, chemotherapy, and/or radiotherapy culminate in a >70% overall 5-year survival. This is the first case reported in 30 years of practice in Côte d'Ivoire, low- and middle-income country (LMIC).

Objective

To summarize clinical data, the significant alternative chemotherapy efficiency and difficulties related to the prognosis evaluation in an LMIC.

Case

A 2-year-old girl had been examined for a large mass in the vulvar region and clitoris. We carried out a biopsy for histopathologist exam. This allows pathologic, genetic, and biological characterization of nonmetastatic botryoid rhabdomyosarcoma. A multidisciplinary team decision of neoadjuvant chemotherapy was retained combining vincristine, cyclophosphamide, and actinomycin D or alternatively with Adriamycin. After 3 weeks of chemotherapy, significant volumetric reduction of tumor was observed. Yet a surgical removal was proposed but not performed because the patient has no longer consulted our medical center and was lost to follow-up. Therefore, we cannot assess the long-term evolution and prognosis.

Conclusion

Embryonal RMS (ERMS) of clitoris is a rare malignant tumor of infant. Histology and immunohistochemistry are essential for diagnostic but unavailable in our context. We want to emphasize on the difficulties encountered in treatment and prognosis assessment. The primary free surgical removal of the vulva with adjuvant chemotherapy and/or radiotherapy must then be implemented in our practice.

A Review of Noninfectious Diseases Masquerading as Acute Mastoiditis

OBJECTIVE

Acute mastoiditis is commonly attributed to infection. Rarely do clinicians encounter cases that do not respond to traditional antibiotics or surgical management. The goal of this study was to systematically review the literature to characterize diseases masquerading as acute infectious mastoiditis.

DATA SOURCES

PubMed, Embase, and Scopus.

REVIEW METHODS

A systematic review was performed to identify all publications that reported on diseases with presentations mimicking acute mastoiditis, defined as postauricular redness, swelling, and tenderness. We included clinical prospective studies, retrospective studies, and case series/reports. Exclusion criteria included non-English articles, letters/commentaries, abstracts, and review articles.

RESULTS

Out of 3339 results, 35 studies met final inclusion criteria. In children, 11 diseases were reported to mimic mastoiditis, including solid tumors, hematologic diseases, and autoimmune/inflammatory diseases. The most common disease in children was Langerhans cell histiocytosis, followed by rhabdomyosarcoma and acute myelogenous leukemia. In adults, 8 additional diseases were reported. The most common disease in adults was squamous cell carcinoma, followed by nasopharyngeal carcinoma and Langerhans cell histiocytosis. Presenting symptoms are reviewed, as well as characteristic radiographic, laboratory, and intraoperative features that may assist with diagnosis. A diagnostic algorithm for atypical cases of acute mastoiditis is proposed.

CONCLUSION

A small but significant group of diseases in children and adults can mimic acute mastoiditis. In such cases, history and examination alone may be insufficient to reach a diagnosis, and further investigation may be necessary. Otolaryngologists should always be mindful of the possibility that noninfectious pathologies may present with a constellation of symptoms similar to mastoiditis.

Creating a data commons: The INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT)

In this article, we will discuss the genesis, evolution, and progress of the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT), which aims to foster international research and collaboration focused on pediatric soft tissue sarcoma. We will begin by highlighting the current state of clinical research for pediatric soft tissue sarcomas, including rhabdomyosarcoma and non-rhabdomyosarcoma soft tissue sarcoma. We will then explore challenges and research priorities, describe the development of INSTRuCT, and discuss how the consortium aims to address key research priorities.

Imaging Hallmarks of Sarcoma Progression Via X-ray Computed Tomography: Beholding the Flower of Evil

Simple Summary

Sarcomas represent the largest group of rare solid tumors that arise from mesenchymal stem cells and are a leading cause of cancer death in individuals younger than 20 years of age. There is an immediate need for the development of an algorithm for the early accurate diagnosis of sarcomas due to the high rate of diagnostic inaccuracy, which reaches up to 30%. X-ray computed tomography is a non-invasive imaging technique used to obtain detailed internal images of the human or animal body in clinical practice and preclinical studies. We summarized the main imaging features of soft tissue and bone sarcomas, and noted the development of new molecular markers to reach tumor type-specific imaging. Also, we demonstrated the possibility of the use X-ray computed microtomography for non-destructive 3D visualization of sarcoma progression in preclinical studies. Finding correlations between X-ray computed tomography modalities and the results of the histopathological specimen examination may significantly increase the accuracy of diagnostics, which leads to the initiation of appropriate management in a timely manner and, consequently, to improved outcomes.

Abstract

Sarcomas are a leading cause of cancer death in individuals younger than 20 years of age and represent the largest group of rare solid tumors. To date, more than 100 morphological subtypes of sarcomas have been described, among which epidemiology, clinical features, management, and prognosis differ significantly. Delays and errors in the diagnosis of sarcomas limit the number of effective therapeutic modalities and catastrophically worsen the prognosis. Therefore, the development of an algorithm for the early accurate diagnosis of sarcomas seems to be as important as the development of novel therapeutic advances. This literature review aims to summarize the results of recent investigations regarding the imaging of sarcoma progression based on the use of X-ray computed tomography (CT) in preclinical studies and in current clinical practice through the lens of cancer hallmarks. We attempted to summarize the main CT imaging features of soft-tissue and bone sarcomas. We noted the development of new molecular markers with high specificity to antibodies and chemokines, which are expressed in particular sarcoma subtypes to reach tumor type-specific imaging. We demonstrate the possibility of the use of X-ray computed microtomography (micro-CT) for non-destructive 3D visualization of solid tumors by increasing the visibility of soft tissues with X-ray scattering agents. Based on the results of recent studies, we hypothesize that micro-CT enables the visualization of neovascularization and stroma formation in sarcomas at high-resolution in vivo and ex vivo, including the novel techniques of whole-block and whole-tissue imaging. Finding correlations between CT, PET/CT, and micro-CT imaging features, the results of the histopathological specimen examination and clinical outcomes may significantly increase the accuracy of soft-tissue and bone tumor diagnostics, which leads to the initiation of appropriate histotype-specific management in a timely manner and, consequently, to improved outcomes.

Pediatric rhabdomyosarcoma incidence and survival in the United States: An assessment of 5656 cases, 2001-2017

BACKGROUND

While rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents, past epidemiology studies of this malignancy used data that covered <30% of the US population. Therefore, we evaluated RMS incidence using data from U.S. Cancer Statistics (USCS) and survival trends using the National Program of Cancer Registries (NPCR), which covers 100% and 94% of the U.S. population, respectively.

METHODS

Incidence and survival were assessed for pediatric patients diagnosed with RMS during 2003-2017 and 2001-2016, respectively. Both demographic and clinical variables were evaluated. Age-adjusted incidence rates, average annual percent change (AAPC), and 5-year relative survival (RS) were calculated, all with corresponding 95% confidence intervals (CIs). Cox regression models were used to evaluate the impact of demographic and clinical variables on survival.

RESULTS

We identified 5656 primary RMS cases in USCS during 2003-2017. The age-adjusted incidence rate was 4.58 per 1 million (95% CI: 4.46-4.70) with an AAPC of 0.3% (95% CI: -0.7 to 1.2%). In NPCR, 5-year RS for all cases was 68.0% (95% CI: 66.6-69.3%). In multivariable analyses, non-Hispanic (NH) Black cases had worse survival compared with NH White cases (hazard ratio [HR] = 1.16, 95% CI: 1.01-1.33).

CONCLUSION

The incidence and survival rates were stable in the largest and most comprehensive population-based analysis for pediatric RMS cases in the U.S. Additionally, we observed a survival disparity among NH Black cases. Findings from this study could inform interventions to address disparities, risk stratification strategies, and clinical trial design.

Primary rhabdomyosarcoma of the ethmoid sinus with orbital extension and metastasis to the pancreatic body

This case report highlights the need for clinicians to monitor patients with rhabdomyosarcoma for pancreatic metastasis to ensure that proper treatment is quickly provided, thereby improving outcomes.

Precision Medicine Highlights Dysregulation of the CDK4/6 Cell Cycle Regulatory Pathway in Pediatric, Adolescents and Young Adult Sarcomas

Simple Summary

This review provides an overview of clinical features and current therapies in children, adolescents, and young adults (AYA) with sarcoma. It highlights the basic and clinical findings on the cyclin-dependent kinases 4 and 6 (CDK4/6) cell cycle regulatory pathway in the context of the precision medicine-based molecular profiles of the three most common types of pediatric and AYA sarcomas—osteosarcoma (OS), rhabdomyosarcoma (RMS), and Ewing sarcoma (EWS).

Abstract

Despite improved therapeutic and clinical outcomes for patients with localized diseases, outcomes for pediatric and AYA sarcoma patients with high-grade or aggressive disease are still relatively poor. With advancements in next generation sequencing (NGS), precision medicine now provides a strategy to improve outcomes in patients with aggressive disease by identifying biomarkers of therapeutic sensitivity or resistance. The integration of NGS into clinical decision making not only increases the accuracy of diagnosis and prognosis, but also has the potential to identify effective and less toxic therapies for pediatric and AYA sarcomas. Genome and transcriptome profiling have detected dysregulation of the CDK4/6 cell cycle regulatory pathway in subpopulations of pediatric and AYA OS, RMS, and EWS. In these patients, the inhibition of CDK4/6 represents a promising precision medicine-guided therapy. There is a critical need, however, to identify novel and promising combination therapies to fight the development of resistance to CDK4/6 inhibition. In this review, we offer rationale and perspective on the promise and challenges of this therapeutic approach.

CD147 Promotes Tumorigenesis via Exosome-Mediated Signaling in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is an aggressive childhood soft-tissue tumor, with propensity for local invasion and distant metastasis. Exosomes are secreted vesicles that mediate paracrine signaling by delivering functional proteins and miRNA to recipient cells. The transmembrane protein CD147, also known as Basigin or EMMPRIN, is enriched in various tumor cells, as well as in tumor-derived exosomes, and has been correlated with poor prognosis in several types of cancer, but has not been previously investigated in RMS. We investigated the effects of CD147 on RMS cell biology and paracrine signaling, specifically its contribution to invasion and metastatic phenotype. CD147 downregulation diminishes RMS cell invasion and inhibits anchorage-independent growth in vitro. While treatment of normal fibroblasts with RMS-derived exosomes results in a significant increase in proliferation, migration, and invasion, these effects are reversed when using exosomes from CD147-downregulated RMS cells. In human RMS tissue, CD147 was expressed exclusively in metastatic tumors. Altogether, our results demonstrate that CD147 contributes to RMS tumor cell aggressiveness, and is involved in modulating the microenvironment through RMS-secreted exosomes. Targeted inhibition of CD147 reduces its expression levels within the isolated exosomes and reduces the capacity of these exosomes to enhance cellular invasive properties.

Malignant Rhabdoid Tumor of the Kidney in a Child With Xeroderma Pigmentosum: Incidence or Coincidence?

Malignant rhabdoid tumor of the kidney (MRTK) is a rare aggressive malignant rhabdoid tumor that mainly affects children. At the onset of the disease, the usual clinical manifestations are gross hematuria, abdominal pain, and abdominal distension. The prognosis remains poor. Patients with rhabdoid tumors (RT) are treated according to institutional preferences that combine surgery, radiation therapy, and chemotherapy. The authors present the rare case of a child with xeroderma pigmentosum (XP) who presented with an abdominal mass accompanied by hematuria and abdominal pain. The radiological and histological results were congruent with the MRTK. The patient received preoperative chemotherapy but unfortunately died of septic shock. This case highlights the importance of being aware of MRTK and its fatal complications, as well as the increased risk of kidney tumors in patients with XP.

An Exceptionally Rare Primary Epithelioid Rhabdomyosarcomas of the Stomach: A Case Report

Rhabdomyosarcoma (RMS) is a common soft tissue tumor in adults, but RMS's causes and risk factors are unknown. We present a case of a 62-year-old man with RMS who presented with feelings of fullness after meals and vomiting for the previous five months with anorexia and weight loss for four months. He reported feeling a rolling mass in his belly that moves from left to right. He was initially diagnosed with gastric outlet obstruction due to stomach carcinoma. During the surgical operation, we noted the gross appearance was unlike typical adenocarcinoma or lymphoma of the stomach. Histopathological evaluation of the specimen confirmed a diagnosis of primary epithelial RMS of the stomach. When treating RMS, expertise in immunohistochemistry, molecular biology, genetics, or ultrastructure may be necessary. Information on the appropriate laboratory investigations and management protocol is limited, but an early diagnosis can change the course of treatment and improve patient outcomes.

Pleomorphic Rhabdomyosarcoma: A Systematic Review with Outcome Analysis and Report of a Rare Abdominal Wall Lesion

Introduction. Pleomorphic rhabdomyosarcoma (RMS) is an aggressive and rare malignant neoplasm with a poor prognosis. As its name suggests, this tumor exhibits extensive pleomorphism with features of skeletal muscle differentiation. Due to its rarity, its diagnosis is often a clinical and pathological challenge. Since only small case series and a few scattered case reports exist in the literature, the impact of different demographic features, tumor site, and/or treatment modality on patient outcomes has yet to be extensively studied. Methods. We report a case of a pleomorphic RMS presenting atypically as an abdominal wall mass. We have also analyzed the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) database to determine the factors affecting the outcome of this neoplasm. Moreover, we present a review and summary of pleomorphic RMS cases arising from the abdominal wall reported in the English language literature. Results. We found two hundred and forty-two cases of pleomorphic RMS in the SEER database. The majority of the patients were diagnosed after the age of 40, with the age of diagnosis showing a unimodal distribution. The majority of the patients were Caucasian (82%) and male (59%). Age of diagnosis, tumor stage, and surgical management significantly affected the patients' outcome, while patients' ethnicity, sex, or tumor site did not affect the outcome. We only found five previously reported cases of pleomorphic RMS arising from the abdominal wall. Conclusions. Pleomorphic RMS arising from the abdominal wall is extremely rare. Our data sheds light on the factors affecting the outcome of pleomorphic RMS. We have also discussed the challenges involving the histopathological diagnosis of this rare neoplasm and how to best approach this task.

Combined inhibition of BET bromodomain and mTORC1/2 provides therapeutic advantage for rhabdomyosarcoma by switching cell death mechanism

Aberrant activation of multiple complex signaling pathways underlies the pathogenesis of rhabdomyosarcoma (RMS), which remains a cause of mortality in approximately 30% of children with RMS. Bromodomain and extraterminal (BET) domain chromatin remodeling regulates several of these pathways. Here, we targeted bromodomain 4 (BRD4) in combination with another molecular metabolic tumor driver, the Akt/mTOR signaling pathway, to provide a highly effective treatment for this neoplasm. We demonstrated that a nexus of these two molecular pathways underlies RMS pathogenesis. Our data show that the combined inhibition of the BET bromodomain and mTORC1/2 signaling abrogates aggressive RMS growth. Thus, the bromodomain inhibitor RVX-208 significantly augmented the therapeutic effects of the dual mTORC1/2 inhibitors, OSI-027 and PP242, both in vitro and in a human xenograft murine model. Drug-treated residual tumors showed a decrease in the activation of underlying signaling mechanisms characterized by a reduction in the expression of p-AKT, p-mTOR, p-p70S6K, cyclin D1, and proliferation. Our ChIP-seq data demonstrated that RVX-208 effectively blocked BRD4 occupancy on its target promoters. ChIP-qPCR assays further confirmed that RVX-208 treatment resulted in a significant decrease in H3K27ac and H4K8ac signals at their target loci. While single RVX-208 treatment induces apoptosis and a single mTORC1/2 inhibitor induces macropinocytosis, their combined treatment led to necroptosis-mediated cell death. These data suggest that combined treatment with drugs targeting BRD4 and mTORC1/2 may be an effective therapeutic intervention for drug-resistant RMS.