Age, stage, and radiotherapy, but not primary tumor site, affects the outcome of patients with malignant rhabdoid tumors

Successful multimodality management of extrarenal extracranial malignant rhabdoid tumour of the left sciatic nerve mimicking a neurofibroma

Extrarenal extracranial malignant rhabdoid tumour (MRT) is a rare and highly aggressive tumour representing <1% of paediatric soft tissue malignancies. Only a few cases of MRT of the thigh arising from the sciatic nerve have been reported in medical literature to date. A 5-year-old girl presented with progressively increasing painless lump in the posterior aspect of the left thigh. A contrast-enhanced magnetic resonance imaging (MRI) of the left thigh showed a 4.7 × 5 × 10.5 cm well-marginated, lobulated, homogeneously enhancing lesion in the posterior compartment of the left thigh along the course of the sciatic nerve. She underwent en bloc excision of the left sciatic nerve tumour and end-to-end anastomosis of the left sciatic nerve with a right sural nerve graft. Histopathological and immunohistochemical examination of the surgical specimen revealed a malignant rhabdoid tumour. INI-1 immunoexpression was lost in the tumour cells. The metastatic workup was essentially normal. Subsequently, she received post-operative radiotherapy to the tumour bed (50.4 Gray in 28 fractions over 5.5 weeks) followed by six cycles of multiagent chemotherapy with ICE (Ifosfamide, Carboplatin, and Etoposide) regimen. On the last follow-up visit, 20 months after surgery, she was in complete clinical and radiological response. Aggressive multimodality management comprising radical resection of tumour, post-operative radiotherapy to the tumour bed, and multiagent chemotherapy with ICE regimen can lead to favourable outcomes in patients with this rare tumour.

Radiation Therapy Plays an Important Role in the Treatment of Atypical Teratoid/Rhabdoid Tumors: Analysis of the EU-RHAB Cohorts and Their Precursors

PURPOSE

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare malignancy of the central nervous system in young children with a dismal prognosis. Prognostic markers have been extensively investigated but have not been validated. The role of radiation therapy (RT) remains controversial. We evaluated the impact of RT as part of multimodality treatment by analyzing data of a European AT/RT cohort.

METHODS AND MATERIALS

We retrospectively analyzed data of the European Registry for Rhabdoid Tumors and its precursors. Primary endpoints were progression-free survival (PFS) and overall survival (OS). Potential impact of prognostic factors was analyzed using univariable and multivariable Cox regression analyses with RT as a time-dependent factor.

RESULTS

Data of 186 children (118 male, 68 female) treated from 1990 to 2016 were evaluable. The median age at diagnosis was 1.57 years (range, 0.01-26.70 years); 47% (87/186) of the patients were under the age of 18 months. Sixty-nine percent (128/186) received RT (focal RT, n = 93; craniospinal treatment with local boost, n = 34; spinal irradiation, n = 1). The median follow-up duration of the entire cohort was 1.73 years (range, 0.06-20.11 years). The estimated PFS and OS rates were 48% (95% CI, 41%-55%) and 72% (95% CI, 65%-78%) at 1 year and 33% (95% CI, 26%-40%) and 49% (95% CI, 41%-56%) at 2 years, respectively. On multivariable analysis, RT was an independent significant prognostic factor for PFS (hazard ratio, 0.45; 95% CI, 0.27-0.75; P = .002) and OS (hazard ratio, 0.54; 95% CI, 0.32-0.93; P = .025).

CONCLUSIONS

This analysis confirms the relevance of local therapies. RT was an independent prognostic factor for outcomes in children experiencing AT/RT. However, long-term sequelae have to be carefully evaluated and considered given the young age at time of RT.

Origins of Second Malignancies in Children and Mutational Footprint of Chemotherapy in Normal Tissues

Pediatric cancers are rare diseases, and children without known germline predisposing conditions who develop a second malignancy during developmental ages are extremely rare. We present four such clinical cases and, through whole-genome and error-correcting ultra-deep duplex sequencing of tumor and normal samples, we explored the origin of the second malignancy in four children, uncovering different routes of development. The exposure to cytotoxic therapies was linked to the emergence of a secondary acute myeloid leukemia. A common somatic mutation acquired early during embryonic development was the driver of two solid malignancies in another child. In two cases, the two tumors developed from completely independent clones diverging during embryogenesis. Importantly, we demonstrate that platinum-based therapies contributed at least one order of magnitude more mutations per day of exposure than aging to normal tissues in these children.

SIGNIFICANCE

Using whole-genome and error-correcting ultra-deep duplex sequencing, we uncover different origins for second neoplasms in four children. We also uncover the presence of platinum-related mutations across 10 normal tissues of exposed individuals, highlighting the impact that the use of cytotoxic therapies may have on cancer survivors. See related commentary by Pacyna and Nangalia, p. 900. This article is featured in Selected Articles from This Issue, p. 897.

Mediastinal malignant rhabdoid tumor in an infant: A rare case report

Mediastinal malignant rhabdoid tumor (MRT) is an exceedingly rare and aggressive neoplasm, particularly uncommon in infants. We present the case of a previously healthy 7-month-old male infant with mediastinal MRT. The patient initially presented with left eyelid ptosis and was otherwise asymptomatic. Initial investigations, including brain MRI, yielded unremarkable results, and the infant was discharged with vitamin B supplements. However, he was readmitted a week later with prolonged fever, poor feeding, diarrhea, and respiratory distress. Despite an initial diagnosis of bronchiolitis/viral respiratory tract infection, the patient's condition rapidly deteriorated. Subsequent evaluation revealed mediastinal MRT as the underlying cause. This case underscores the diagnostic challenges associated with mediastinal MRT in infants and highlights the importance of considering rare neoplastic etiologies in atypical clinical presentations.

Malignant Extrarenal Rhabdoid tumor derived from the greater omentum: A case report and literature review

BACKGROUND

Malignant extrarenal rhabdoid tumor (MERT) is a rare and highly metastatic tumor, which is more than 75% of patients dying within 6 months of initial diagnosis, and it often leads to misdiagnosis and delayed treatment.

CASE

This paper reports a 16-year-old girl who presented with the chief complaint of acute abdominal pain. She underwent laparoscopic exploration and excisional biopsy, then pathological examination and immunohistochemistry revealed "extrarenal malignant rhabdomyoma." One month after operation, she died of intra-abdominal hemorrhage and multiple organ dysfunction.

CONCLUSION

MERT were often misdiagnosed and had a poor prognosis. The surgery and chemotherapy are usually beneficial to prolong the survival time of patients with MERT.

Atypical teratoid rhabdoid tumor in a lower middle‑income country: Challenges to cure

Atypical teratoid rhabdoid tumor (ATRT) is a rare type of potentially fatal childhood brain tumor. The present study aimed to examine the overall survival (OS) and event-free survival (EFS) outcomes of pediatric patients with ATRT and to analyze the impact of different prognostic factors, including age, sex, tumor site and size, metastatic disease, the extent of resection, radiotherapy, and chemotherapy, on survival. The present study included 47 patients with ATRT treated at the Children's Cancer Hospital of Egypt (Cairo, Egypt) between July 2007 and December 2017. These patients were treated according to the Dana-Farber Cancer Institute protocol 02-294 for 51 weeks. Various prognostic factors, including age, sex, tumor size and initial metastatic status, exhibited no impact on the radiological response measured at 6 weeks and at the end of treatment. The primary tumor site significantly affected the response to treatment at 6 weeks (P=0.008). Toxicity-related mortality occurred in 29.8% of patients. The median duration of the treatment protocol was 66.9 weeks. The duration of treatment was in the present cohort was longer than the actual 51 weeks of the protocol due to prolonged supportive care of the included patients. Patients who encountered toxicity received reduced dose of chemotherapy in the subsequent cycles in the protocol. Age, initial metastatic status, tumor site and resection extent did not significantly affect the patient outcomes. Preoperative tumor size significantly affected the EFS (P=0.03) and OS (P=0.04). Radiotherapy administration significantly affected the OS (P<0.001) and EFS (P<0.001). The median EFS and OS of patients were 9.3 and 10.3 months, respectively. A total of 24 (51.1%) patients exhibited disease progression or recurrence. The progression sites were local (n=6), metastatic (n=9) or both local and metastatic (n=9). The results of the present study demonstrated that the therapeutic regimen should be patient-adjusted to maintain the treatment intensity and avoid toxicity-related mortality. In lower middle-income countries, short and intensified induction followed by consolidation of treatment, either by single or tandem autologous stem cell transplant, is needed to avoid prolonged exposure to myelosuppression and toxicity-related mortality.

Extracranial malignant rhabdoid tumors in children: high mortality even with the help of an aggressive clinical approach

This paper aims to explore the epidemiology, clinical characteristics, and prognosis of extracranial malignant rhabdoid tumors (eMRTs) in children. A systematic review and meta-analysis of studies published in PUBMED, MEDLINE, Web of Science, Embase, Cochrane, and China National Knowledge Infrastructure (CNKI) was conducted. The search was limited to studies published between Jan 1, 1990 to Dec 31, 2022, with the last search done on Jan 31, 2023. We identified 496 papers through the literature search, and 12 retrospective cohort studies with 398 patients were included. The pooled age at diagnosis for malignant rhabdoid tumor of the kidney (MRTK) was 10.009 months (95%CI (7.542-12.476)), while extracranial malignant rhabdoid tumor (EERT) was 25.917 months (95%CI (17.304-34.530)). Among the 398 patients with eMRTs, chemotherapy treatment rate (86.8% (95%CI (74.4-96.0%))) was more frequently than radiotherapy treatment (45.4% (95%CI (38.1-52.6%))). The rate of metastasis in all patients was 41.4% (95%CI (33.9-48.9%)), in which the lung metastasis was occupied 70.4% (95%CI (58.0-81.6%)). SMARCB1/INI1 mutation was up to 93.2% (95%CI (81.3-99.8%)). The rate of total surgical resection was 50.4% (95%CI (35.2-65.6%)), while pooled proportion of death in all patients was 68.7% (95%CI (56.9-79.5%)).     Conclusion: EMRTs are highly malignant tumors associated with high mortality rates. The loss of SMARCB1/INI1 gene and the protein expression is observed in the vast majority of eMRTs patients. Patients that suffered MRTK are younger than patients with extrarenal EERT and are more prone to lung metastasis, but there is no significant difference in overall survival, possibly due to the higher rate of R0 resection of primary tumors in MRTK.     Trial registration: The study was registered on PROSPERO with registration number CRD42023400985. What is Known: • Malignant rhabdoid tumor (MRT) is a rare and highly malignant tumor that may originate from embryonic stem cells. The incidence of MRT is exceptionally low, estimated at 0.00006%. • Malignant rhabdoid tumor of the kidney (MRTK) and extrarenal extra-cranial malignant rhabdoid tumor (EERT) tend to manifest between 11 to 18 months of age, with a 5-year survival rate of approximately 17%-36%. What is New: • There is no comprehensive meta-analysis or large-scale case series that reported to systematically introduce the eMRTs clinic outcome and prog-nosis based on largely pooled data. • This study performed a meta-analysis through an extensive literature search and clinical data analysis in order to mainly explore the clinical characteris-tics and prognosis of eMRTs, improving the understanding of eMRTs in children..

Prognostic Factors in Pediatric Alveolar Rhabdomyosarcoma: SEER Analysis of 277 Cases

Alveolar rhabdomyosarcoma (ARMS) is a rare but highly aggressive cancer predominantly affecting children and adolescents. This study explores prognostic factors for pediatric and adolescent ARMS, using the Surveillance, Epidemiology, and End Results (SEER) database. Leveraging SEER data (2000-2019), we analyzed 277 cases. Employing Kaplan-Meier survival analysis and Cox proportional hazards models, we identified significant prognostic factors. Gender distribution was nearly equal (56.0% boys, 44.0% girls), with the majority (70.8%) from the white ethnic group. Primary tumors were predominantly in extremities (37.2%). Distant metastases significantly increased mortality risk (hazard ratio [HR], 3.13; 95% CI: 2.14-4.58) and regional lymph node involvement raised mortality risk (HR, 1.36; 95% CI: 0.96-1.92). Chemotherapy-only treatment had higher mortality risk than chemoradiotherapy (HR, 1.16; 95% CI: 0.97-2.67). Conclusively, our study identifies distant metastases, regional lymph node involvement, and treatment modality as crucial predictors of overall survival in pediatric ARMS.

Role of radiotherapy in the management of rare gynaecological cancers

There are a large number of gynaecological cancers with rare histologies, for which the available data are limited and usually retrospective. Because of their rarity and poor prognosis, the management of these cancers must be centralized in expert centres, for both histological diagnosis and treatment. With the exception of sarcomas, most endometrial or cervical cancers with rare histologies respond to the same radiation treatment modalities than cancers with more common histologies, although there are some specificities regarding treatments such as neuroendocrine carcinomas (chemotherapy with platinum and etoposide, major role of surgery). For localized or locally advanced ovarian cancer, external beam radiotherapy has a role in the management of hypercalcaemic small cell carcinoma of the ovary. This article summarizes the current role of external beam radiotherapy and brachytherapy in the management of cancers of the uterine cervix, uterine corpus and ovaries, with rare or very rare histologies, and with localized or locally advanced stages.

Targeting epigenetic aberrations of sarcoma in CRISPR era

Sarcomas are rare malignancies that exhibit diverse biological, genetic, morphological, and clinical characteristics. Genetic alterations, such as gene fusions, mutations in transcriptional machinery components, histones, and DNA methylation regulatory molecules, play an essential role in sarcomagenesis. These mutations induce and/or cooperate with specific epigenetic aberrations required for the growth and maintenance of sarcomas. Appropriate mouse models have been developed to clarify the significance of genetic and epigenetic interactions in sarcomas. Studies using the mouse models for human sarcomas have demonstrated major advances in our understanding the developmental processes as well as tumor microenvironment of sarcomas. Recent technological progresses in epigenome editing will not only improve the studies using animal models but also provide a direct clue for epigenetic therapies. In this manuscript, we review important epigenetic aberrations in sarcomas and their representative mouse models, current methods of epigenetic editing using CRISPR/dCas9 systems, and potential applications in sarcoma studies and therapeutics.

Targeting EZH2 in SMARCB1-deficient sarcomas: Advances and opportunities to potentiate the efficacy of EZH2 inhibitors

Soft tissue sarcomas (STSs) are rare mesechymal malignancies characterized by distintive molecular, histological and clinical features. Many STSs are considered as predominatly epigenetic diseases due to underlying chromatin deregulation. Discovery of deregulated functional antagonism between the chromatin remodeling BRG1/BRM-associated (BAFs) and the histone modifying Polycomb repressor complexes (PRCs) has provided novel actionable targets. In epithelioid sarcoma (ES), extracranial, extrarenal malignant rhabdoid tumors (eMRTs) and synovial sarcoma (SS), the total or partial loss of the BAF core subunit SMARCB1, driven by different alterations, is associated with PRC2 deregulation and dependency on its enzymatic subunit, EZH2. In these SMARCB1-deficient STSs, aberrant EZH2 expression and/or activity emerged as a druggable vulnerability. Although preclinical investigation supported EZH2 targeting as a promising therapeutic option, clinical studies demonstrated a variable response to EZH2 inhibitors. Actually, whereas the clinical benefit recorded in ES patients prompted the FDA approval of the EZH2 inhibitor tazemetostat, the modest and sporadic responses observed in eMRT and SS patients highlighted the need to deepen mechanistic as well as pharmacological investigations to improve drug effectiveness. We summarize the current knowledge of different mechanisms driving SMARCB1 deficiency and EZH2 deregulation in ES, eMRT and SS along with preclinical and clinical studies of EZH2-targeting agents. Possible implication of the PRC2- and enzymatic-independent functions of EZH2 and of its homolog, EZH1, in the response to anti-EZH2 agents will be discussed together with combinatorial strategies under investigation to improve the efficacy of EZH2 targeting in these tumors.

Recent insights into the SWI/SNF complex and the molecular mechanism of hSNF5 deficiency in rhabdoid tumors

Genetic information encoded by DNA is packaged in the nucleus using the chromatin structure. The accessibility of transcriptional elements in DNA is controlled by the dynamic structural changes of chromatin for the appropriate regulation of gene transcription. Chromatin structure is regulated by two general mechanisms, one is histone modification and the other is chromatin remodeling in an ATP-dependent manner. Switch/sucrose nonfermentable (SWI/SNF) complexes utilize the energy from ATP hydrolysis to mobilize nucleosomes and remodel the chromatin structure, contributing to conformational changes in chromatin. Recently, the inactivation of encoding genes for subunits of the SWI/SNF complexes has been documented in a series of human cancers, accounting for up to almost 20% of all human cancers. For example, human SNF5 (hSNF5), the gene that encodes a subunit of the SWI/SNF complexes, is the sole mutation target that drives malignant rhabdoid tumors (MRT). Despite remarkably simple genomes, the MRT has highly malignant characteristics. As a key to understanding MRT tumorigenesis, it is necessary to fully examine the mechanism of chromatin remodeling by the SWI/SNF complexes. Herein, we review the current understanding of chromatin remodeling by focusing on SWI/SNF complexes. In addition, we describe the molecular mechanisms and influences of hSNF5 deficiency in rhabdoid tumors and the prospects for developing new therapeutic targets to overcome the epigenetic drive of cancer that is caused by abnormal chromatin remodeling.

Establishment and characterization of NCC-MRT1-C1: a novel cell line of malignant rhabdoid tumor

Malignant rhabdoid tumor (MRT) is a sarcoma histologically characterized by rhabdoid cells and genetically characterized by loss of function of the chromatin remodeling complex SWI/SNF induced by SMARCB1 gene deficiency. MRT mainly occurs in children, may arise in various locations, but is predominantly in the central nervous system (CNS) and kidney. Although MRT exhibits poor prognosis, standard treatment has not yet been established due to its extreme rarity. Patient-derived cancer cell lines are critical tools for basic and pre-clinical research in the development of chemotherapy. However, none of the MRT cell lines was derived from adult patients, and only one cell line was derived from the MRT of a soft tissue, despite the clinical behavior of MRT varying according to patient age and anatomic site. Herein, we reported the first cell line of MRT isolated from the soft tissue of an adult patient and named it NCC-MRT1-C1. NCC-MRT1-C1 cells showed a biallelic loss of the SMARCB1 gene. NCC-MRT1-C1 cells demonstrated rapid proliferation, spheroid formation, invasion capability in vitro, and tumorigenesis in nude mice. Screening of antitumor agents in NCC-MRT1-C1 cells resulted in the identification of six effective drugs. In conclusion, we report the first MRT cell line from the soft tissue of an adult patient. We believe that NCC-MRT1-C1 is a useful tool for developing novel chemotherapies for MRT.

Clinical predictors of survival for patients with atypical teratoid/rhabdoid tumors

PURPOSE

Atypical teratoid/rhabdoid tumors (AT/RTs) are malignant central nervous system (CNS) neoplasms of the young. Our study analyzed a large AT/RT cohort from the National Cancer Database (NCDB) to elucidate predictors of short-term mortality and overall survival (OS).

METHODS

Information was collected on patients with histologically confirmed AT/RT using the NCDB (2004-2016). Kaplan-Meier analysis indicated OS. Prognostic factors for 30-day mortality, 90-day mortality, and OS were determined via multivariate Cox proportional hazards (CPH) and logistic regression models.

RESULTS

Our cohort of 189 patients had a median age of 1 year (IQR [1, 4]) and tumor size of 4.7 ± 2.0 cm at diagnosis. Seventy-two percent were under 3 years old; 55.6% were male and 71.0% were Caucasian. Fifty (27.2%) patients received only surgery (S) (OS = 5.91 months), 51 (27.7%) received surgery and chemotherapy (S + CT) (OS = 11.2 months), and 9 (4.89%) received surgery and radiotherapy (S + RT) (OS = 10.3 months). Forty-five (24.5%) received S + CT + RT combination therapy (OS = 45.4 months), 13 (17.1%) received S + CT + BMT/SCT (bone marrow or stem cell transplant) (OS = 55.5 months), and 16 (8.70%) received S + CT + RT + BMT/SCT (OS = 68.4 months). Bivariate analysis of dichotomized age (HR = 0.550, 95% CI [0.357, 0.847], p = 0.0067) demonstrated significantly increased patient survival if diagnosed at or above 1 year old. On multivariate analysis, administration of S + CT + RT, S + CT + BMT/SCT, or S + CT + RT + BMT/SCT combination therapy predicted significantly (p < 0.05) increased OS compared to surgery alone.

CONCLUSION

AT/RTs are CNS tumors where those diagnosed under 1 year old have a significantly worse prognosis. Our study demonstrates that while traditional CT, RT, and BMT/SCT combination regimens prolong life, overall survival in this population is still low.

Infants and Newborns with Atypical Teratoid Rhabdoid Tumors (ATRT) and Extracranial Malignant Rhabdoid Tumors (eMRT) in the EU-RHAB Registry: A Unique and Challenging Population

Simple Summary

Malignant rhabdoid tumors (MRT) are deadly tumors that predominantly affect infants and young children. Even when considering the generally young age of these patients, the treatment of infants below the age of six months represents a particular challenge due to the vulnerability of this patient population. The aim of our retrospective study was to assess the available information on prognostic factors, genetics, toxicity of treatment and long-term outcomes of MRT. We confirmed that, in a cohort of homogenously treated infants with MRT, significant predictors of outcome were female sex, localized stage, absence of a GLM and maintenance therapy, and these significantly favorably influence prognosis. Stratification-based biomarker-driven tailored trials may be a key option to improve survival rates.

Abstract

Introduction: Malignant rhabdoid tumors (MRT) predominantly affect infants and young children. Patients below six months of age represent a particularly therapeutically challenging group. Toxicity to developing organ sites limits intensity of treatment. Information on prognostic factors, genetics, toxicity of treatment and long-term outcomes is sparse. Methods: Clinical, genetic, and treatment data of 100 patients (aged below 6 months at diagnosis) from 13 European countries were analyzed (2005–2020). Tumors and matching blood samples were examined for SMARCB1 mutations using FISH, MLPA and Sanger sequencing. DNA methylation subgroups (ATRT-TYR, ATRT-SHH, and ATRT-MYC) were determined using 450 k / 850 k-profiling. Results: A total of 45 patients presented with ATRT, 29 with extracranial, extrarenal (eMRT) and 9 with renal rhabdoid tumors (RTK). Seventeen patients demonstrated synchronous tumors (SYN). Metastases (M+) were present in 27% (26/97) at diagnosis. A germline mutation (GLM) was detected in 55% (47/86). DNA methylation subgrouping was available in 50% (31 / 62) with ATRT or SYN; for eMRT, methylation-based subgrouping was not performed. The 5-year overall (OS) and event free survival (EFS) rates were 23.5 ± 4.6% and 19 ± 4.1%, respectively. Male sex (11 ± 5% vs. 35.8 ± 7.4%), M+ stage (6.1 ± 5.4% vs. 36.2 ± 7.4%), presence of SYN (7.1 ± 6.9% vs. 26.6 ± 5.3%) and GLM (7.7 ± 4.2% vs. 45.7 ± 8.6%) were significant prognostic factors for 5-year OS. Molecular subgrouping and survival analyses confirm a previously described survival advantage for ATRT-TYR. In an adjusted multivariate model, clinical factors that favorably influence the prognosis were female sex, localized stage, absence of a GLM and maintenance therapy. Conclusions: In this cohort of homogenously treated infants with MRT, significant predictors of outcome were sex, M-stage, GLM and maintenance therapy. We confirm the need to stratify which patient groups benefit from multimodal treatment, and which need novel therapeutic strategies. Biomarker-driven tailored trials may be a key option.

Update of pediatric soft tissue tumors with review of conventional MRI appearance-part 2: vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas

There are numerous soft tissue tumors and tumor-like conditions in the pediatric population. Magnetic resonance imaging is the most useful modality for imaging these lesions. Although certain soft tissue lesions exhibit magnetic resonance features characteristic of a specific diagnosis, most lesions are indeterminate, and a biopsy is necessary for diagnosis. We provide a detailed update of soft tissue tumors and tumor-like conditions that occur in the pediatric population, emphasizing each lesion's conventional magnetic resonance imaging appearance, using the recently released 5^th edition of the World Health Organization Classification of Soft Tissue and Bone Tumors as a guide. In part one of this review, pediatric tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors are discussed. In part two, vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas are reviewed. Per the convention of the WHO, these lesions involve the connective, subcutaneous, and other non-parenchymatous organ soft tissues, as well as the peripheral and autonomic nervous system.

Current and Emerging Therapeutic Approaches for Extracranial Malignant Rhabdoid Tumors

Extracranial malignant rhabdoid tumors (extracranial MRT) are rare, highly aggressive malignancies affecting mainly infants and children younger than 3 years. Common anatomic sites comprise the kidneys (RTK – rhabdoid tumor of kidney) and other soft tissues (eMRT – extracranial, extrarenal malignant rhabdoid tumor). The genetic origin of these diseases is linked to biallelic pathogenic variants in the genes SMARCB1, or rarely SMARCA4, encoding subunits of the SWI/SNF chromatin-remodeling complex. Even if extracranial MRT seem to be quite homogeneous, recent epigenome analyses reveal a certain degree of epigenetic heterogeneity. Use of intensified therapies has modestly improved survival for extracranial MRT. Patients at standard risk profit from conventional therapies; most high-risk patients still experience a dismal course and often therapy resistance. Discoveries of clinical and molecular hallmarks and the exploration of experimental therapeutic approaches open exciting perspectives for clinical and molecularly stratified experimental treatment approaches. To ultimately improve the outcome of patients with extracranial MRTs, they need to be characterized and stratified clinically and molecularly. High-risk patients need novel therapeutic approaches including selective experimental agents in phase I/II clinical trials.

A Systematic Review and Meta-Analysis of Malignant Rhabdoid and Small Cell Undifferentiated Liver Tumors: A Rational for a Uniform Classification

Simple Summary

Malignant rhabdoid tumors of the liver are very rare pediatric liver tumors with a devastating prognosis. It is currently unclear which histological subtypes of pediatric liver tumors belong to this entity and how these tumors should be treated. In this systematic review with meta-analysis, we analyzed all reports on pediatric patients with malignant rhabdoid liver tumors, but also with so-called small cell undifferentiated liver tumors. This is another rare liver tumor subtype that has recently been regarded to belong to the entity of rhabdoid tumors by some authors. The main result of this study is that these two tumor subtypes show large overlap on several levels and even mixtures of both histological patterns have been documented. Our meta-analysis provides an evidence base for the recommendation to classify these two tumor subtypes as one entity. We showed that treatment of these tumors with hepatoblastoma directed chemotherapy is ineffective and that a therapy with chemotherapy regimens initially applied for soft tissue sarcoma is associated with a significantly better survival. This study represents the highest level of evidence available for these rare liver tumors.

Abstract

Background: Rhabdoid liver tumors in children are rare and have a devastating prognosis. Reliable diagnosis and targeted treatment approaches are urgently needed. Immunohistochemical and genetic studies suggest that tumors formerly classified as small cell undifferentiated hepatoblastoma (SCUD) belong to the entity of malignant rhabdoid tumors of the liver (MRTL), in contrast to hepatoblastomas with focal small cell histology (F-SCHB). This may have relevant implications on therapeutic approaches. However, studies with larger cohorts investigating the clinical relevance of the histological and genetic similarities for patients are lacking. Purpose: To analyze possible similarities and differences in patient characteristics, tumor biology, response to treatment, and clinical course of patients with MRTL, SCUD and F-SCHB. Applied therapeutic regimens and prognostic factors are investigated. Methods: A systematic literature search of MEDLINE, Web of Science, and CENTRAL was performed for this PRISMA-compliant systematic review. All studies of patients with MRTL, SCUD and F-SCHB that provided individual patient data were included. Demographic, histological, and clinical characteristics of the three subgroups were compared. Overall survival (OS) was estimated with the Kaplan–Meier method and prognostic factors investigated in a multivariable Cox regression model. Protocol registered: PROSPERO 2021 CRD42021258760. Results: Fifty-six studies with a total of 118 patients were included. The two subgroups MRTL and SCUD did not differ significantly in baseline patient characteristics. However, heterogenous diagnostic and therapeutic algorithms were applied. Large histological and clinical overlap between SCUD and MRTL could be shown. Two-year OS was 22% for MRTL and 13% for SCUD, while it was significantly better in F-SCHD (86%). Chemotherapeutic regimens for hepatoblastoma proved to be ineffective for both SCUD and MRTL, but successful in F-SCHB. Soft tissue sarcoma chemotherapy was associated with significantly better survival for MRTL and SCUD, but was rarely applied in SCUD. Patients who did not undergo surgical tumor resection had a significantly higher risk of death. Conclusions: While F-SCHB is a subtype of HB, SCUD should be classified and treated as a type of MRTL. Surgical tumor resection in combination with intensive, multi-agent chemotherapy is the only chance for cure of these tumors. Targeted therapies are highly needed to improve prognosis. Currently, aggressive regimens including soft tissue sarcoma chemotherapy, extensive resection, radiotherapy or even liver transplantation are the only option for affected children.

Uncommon and peculiar soft tissue sarcomas: Multidisciplinary review and practical recommendations. Spanish Group for Sarcoma research (GEIS -GROUP). Part II

Among all Soft Tissue sarcomas there are some subtypes with low incidence and/or peculiar clinical behaviour, that need to be consider separately. Most of them are orphan diseases, whose biological characteristics imply a clearly different diagnostic and therapeutic approach from other more common sarcoma tumors. We present a brief and updated multidiciplinary review, focused on practical issues, aimed at helping clinicians in decision making. In this second part we review these subtypes: Alveolar Soft Part Sarcoma, Epithelioid Sarcoma, Clear Cell Sarcoma, Desmoplastic Small Round Cell Tumor, Rhabdoid Tumor, Phyllodes Tumor, Tenosynovial Giant Cell Tumors, Myoepithelial Tumor, Perivascular Epithelioid Cell Neoplasms (PEComas), Extraskeletal Myxoid Chondrosarcoma, NTRK-fusions Sarcomas. Most of them present their own radiological and histopathological feautures, that are essential to know in order to achieve early diagnosis. In some of them, molecular diagnosis is mandatory, not only in the diagnosis, but also to plan the treatment. On the other hand, and despite the low incidence, a great scientific research effort has been made to achieve new treatment opportunities for these patients even with approved indications. These include new treatments with targeted therapies and immunotherapy, which today represent possible therapeutic options. It is especially important to be attentive to new and potential avenues of research, and to promote the conduct of specific clinical trials for rare sarcomas.

Characteristics and Outcomes in Pediatric Non-Central Nervous System Malignant Rhabdoid Tumors: A Report from the National Cancer Database

BACKGROUND

Pediatric non-central nervous system (CNS) malignant rhabdoid tumors (MRTs) are rare and aggressive malignancies without standard treatment strategies. The National Cancer Database (NCDB) was utilized to describe the incidence, characteristics, treatment strategies, and outcomes in pediatric patients.

METHODS

Patients <18 years of age and diagnosed with non-CNS MRTs were analyzed from the NCDB from 2004 to 2014. Log-rank tests compared differences in Kaplan-Meier survival distributions. Univariate and multivariable Cox proportional hazard regression models identified predictors of mortality.

RESULTS

Overall, 202 patients were identified. Soft tissue tumors were most common and metastatic disease was present at diagnosis in 34.2% of patients. The 1- and 5-year overall survival (OS) rates were 48.8% and 35.9%, respectively. Multivariable analysis revealed that age <1 year and the presence of metastasis were negative prognostic indicators (p = 0.058). The 1- and 5-year OS rates were 59.9% and 46.5%, respectively, for patients who received surgical intervention (n = 143) compared with 12.3% and 7.4%, respectively, for those treated nonoperatively (n = 59; p < 0.01). Surgical resection was associated with improved outcomes on univariate analysis, although it was no longer an independent predictor of survival on multivariate analysis (p = 0.18). In the cohort of surgical patients, the presence of residual disease trended towards clinically significant worse outcomes (p = 0.13).

CONCLUSIONS

Patients with non-CNS MRTs who were diagnosed in infancy and had metastatic disease had worse survival outcomes. Although surgical resection was associated with improved survival in non-CNS MRTs, it was not independently associated with survival on multivariate analysis. Efforts to improve survival may instead depend on improving chemotherapeutic strategies and developing targeted therapies.

An analysis of the diagnosis, clinical characteristics, treatment, and survival outcomes of 36 extracranial malignant rhabdoid tumor patients

BACKGROUND

Extracranial malignant Rhabdoid tumors (eMRTs) are rare but aggressive lesions in young children. This work aimed to review and analyze the diagnosis, clinical characteristics, treatment, and survival of eMRTs so as to summarize experience for future therapy.

METHODS

A total of 36 eMRT cases were treated between January 2008 and August 2019 according to Shanghai Children's Medical Center (SCMC) multimodal protocol of mixed surgery, radiation and chemotherapy involving vincristine, carboplatin, doxorubicin, etoposide, cyclophosphamide and ifosfamide. We collected information including: age at diagnosis, tumor location, disease stage, therapy, outcomes, etc. Overall survival (OS) and event free survival (EFS) were calculated and risk factors for survival were analyzed.

RESULTS

The patients had a median age of 1.80 years at diagnosis (range, 1.4 m-13.42 years), and were followed up for 9.17 months in median (range, 4 d-11.14 y). A total of 16 patients achieved complete remission (CR), and 7 survived without reoccurrence till December 2019. The 3-year EFS was 17.4% (95% CI: 11.0-23.8%) with a 3-year OS of 23.4% (95% CI: 15.8-31.0%). Recurrence was found only in children younger than the median age (1.80 y). Localized staging (Log Rank P=0.039 for OS and P=0.021) and older age (Log Rank P=0.016 for OS and P=0.002 for EFS) were associated with improved outcome. Younger age (Cox regression, OS, OR =2.610, 95% CI: 1.147-5.937, P=0.022; EFS, OR =3.401, 95% CI: 1.495-7.752, P=0.004) were independent risk factors for death and recurrence.

CONCLUSIONS

Those eMRTs treated according to SCMC protocol turned out to have poor outcomes. Higher staging at diagnosis and reoccurrence in younger patients remain major threats to the prognosis.

Malignant rhabdoid tumor of the kidney in an adult with loss of INI1 expression and mutation in the SMARCB1 gene

A 57-year-old man with left flank pain was referred to our institute. Computed tomography scans revealed two enhancing masses in the left kidney. The clinical diagnosis was renal cell carcinoma (RCC). He underwent a radical nephrectomy with an adrenalectomy. Two well-circumscribed solid masses in the hilum and the lower pole (4.5 × 3.5 cm and 7.0 × 4.1 cm) were present. Poorly cohesive uniform round to polygonal epithelioid cells making solid sheets accounted for most of the tumor area. The initial diagnosis was RCC, undifferentiated with rhabdoid features. As the tumor showed loss of INI1 expression and a mutation in the SMARCB1 gene on chromosome 22, the revised diagnosis was a malignant rhabdoid tumor (MRT) of the kidney. To date, only a few cases of renal MRT in adults have been reported. To the best of our knowledge, this is the first report of MRT in the native kidney of an adult demonstrating a SMARCB1 gene mutation, a hallmark of MRT.

Advances in the Diagnosis and Management of Neonatal Sarcomas

Neonatal sarcomas comprise a heterogeneous group of rare soft tissue neoplasms that present unique diagnostic and therapeutic challenges. Recent advances in molecular profiling have improved diagnostic capabilities and reveal novel therapeutic targets. Clinical trials demonstrate differences in behavior between sarcoma subtypes that allow for better clinical management. Surgical resection has been replaced with a multimodal approach that includes chemotherapy and radiotherapy. Despite these advances, neonates with sarcoma continue to fare worse than histologically similar sarcomas in older children, likely reflecting differences in tumor biology and the complexities of neonatal medicine. This review focuses on recent advances in managing neonatal sarcomas.

Factors Affecting the Outcomes of Patients with Malignant Rhabdoid Tumors: A Population-Based Study

Objective: Malignant rhabdoid tumor (MRT) is a rare but aggressive malignancy. It has been a long time since data on this tumor have been updated. Methods: We retrospectively reviewed patients from the SEER database who were pathologically diagnosed with MRT and analyzed incidence rates, clinical features and survival using Stata 12.0. Results: In total, 544 patients were included in the epidemiological analysis. There were two peak periods of MRT incidence: patients younger than 4 years and those older than 70 years. Further survival analysis showed that the survival of children (especially younger than 1 year) was markedly worse than that of adults (P<0.01), and different primary sites were associated with different age groups and survival outcomes. The central nervous system (CNS) was the most common primary site (50.00%), followed by the kidney (15.66%). Patients with MRTs that originated from the digestive system experienced worse survival outcomes than those with MRTs originating from other locations. Primary site surgery conferred survival benefits to patients with renal and digestive system MRTs (HR = 0.06, CI: 0.02-0.23, P<0.01; HR=0.10, CI: 0.02-0.48, P<0.01), whereas radiotherapy conferred benefits to patients with CNS, bone and soft tissue MRTs (HR=0.22, CI: 0.15-0.34, P<0.01; HR=0.44, CI: 0.21-0.90 P=0.03). Conclusions: Our results indicate that age and the primary site of MRT are critical clinical factors that affect patient survival and treatment choices. Primary site tumor resection should be considered for renal and digestive system MRTs, and systematic therapy, including surgery and radiotherapy, should be recommended for the treatment of CNS, bone and soft tissue MRTs.

Clinical and genetic risk factors define two risk groups of extracranial malignant rhabdoid tumours (eMRT/RTK)

INTRODUCTION

Extracranial rhabdoid tumours are rare, highly aggressive malignancies primarily affecting young children. The EU-RHAB registry was initiated in 2009 to prospectively collect data of rhabdoid tumour patients treated according to the EU-RHAB therapeutic framework.

METHODS

We evaluated 100 patients recruited within EU-RHAB (2009-2018). Tumours and matching blood samples were examined for SMARCB1 mutations by sequencing and cytogenetics.

RESULTS

A total of 70 patients presented with extracranial, extrarenal tumours (eMRT) and 30 with renal rhabdoid tumours (RTK). Nine patients demonstrated synchronous tumours. Distant metastases at diagnosis (M+) were present in 35% (35/100), localised disease (M0) with (LN+) and without (LN-) loco-regional lymph node involvement in 65% (65/100). SMARCB1 germline mutations (GLM) were detected in 21% (17/81 evaluable) of patients. The 5-year overall survival (OS) and event-free survival (EFS) rates were 45.8 ± 5.4% and 35.2 ± 5.1%, respectively. On univariate analyses, age at diagnosis (≥12 months), M0-stage, absence of synchronous tumours, absence of a GLM, gross total resection (GTR), radiotherapy and achieving a CR were significantly associated with favourable outcomes. In an adjusted multivariate model presence of a GLM, M+ and lack of a GTR were the strongest significant negative predictors of outcome.

CONCLUSIONS

We suggest to stratify patients with localised disease (M0), GTR+ and without proof of a GLM (5-year OS 72.2 ± 9.9%) as 'standard risk'. Patients presenting with one of the features M+ and/or GTR- and/or GLM+ belong to a high risk group (5-year, OS 32.5 ± 6.2%). These patients need novel therapeutic strategies such as combinations of targeted agents with conventional chemotherapy or novel experimental approaches ideally within international phase I/II trials.

The forkhead box M1 (FOXM1) expression and antitumor effect of FOXM1 inhibition in malignant rhabdoid tumor

PURPOSE

Malignant rhabdoid tumor (MRT) is a rare, highly aggressive sarcoma with an uncertain cell of origin. Despite the existing standard of intensive multimodal therapy, the prognosis of patients with MRT is very poor. Novel antitumor agents are needed for MRT patients. Forkhead box transcription factor 1 (FOXM1) is overexpressed and is correlated with the pathogenesis in several human malignancies. In this study, we identified the clinicopathological and prognostic values of the expression of FOXM1 and its roles in the progression of MRT.

METHODS

We investigated the FOXM1 expression levels and their clinical significance in 23 MRT specimens using immunohistochemistry and performed clinicopathologic and prognostic analyses. We also demonstrated correlations between the downregulation of FOXM1 and oncological characteristics using small interfering RNA (siRNA) and FOXM1 inhibitor in MRT cell lines.

RESULTS

Histopathological analyses revealed that primary renal MRTs showed significantly low FOXM1 protein expression levels (p = 0.032); however, there were no significant differences in other clinicopathological characteristics or the survival rate. FOXM1 siRNA and FOXM1 inhibitor (thiostrepton) successfully downregulated the mRNA and protein expression of FOXM1 in vitro and the downregulation of FOXM1 inhibited cell proliferation, drug resistance to chemotherapeutic agents, migration, invasion, and caused the cell cycle arrest and apoptosis of MRT cell lines. A cDNA microarray analysis showed that FOXM1 regulated FANCD2 and NBS1, which are key genes for DNA damage repair.

CONCLUSION

This study demonstrates that FOXM1 may serve as a promising therapeutic target for MRT.

Small cell carcinoma of the ovary hypercalcemic type (SCCOHT): Comprehensive management of a newly diagnosed young adult

SCCOHT is an aggressive malignancy linked to alterations of SMARCA4. We describe the diagnosis and therapy of a 32 year old who received multi-agent chemotherapy and underwent a second look operation with HIPEC followed by high-dose chemotherapy with stem cell transplant. Supportive care, oncofertility, and genetic counseling are described.

Genomic and Immunologic Characterization of INI1-Deficient Pediatric Cancers

PURPOSE

Several aggressive pediatric cancers harbor alterations in SMARCB1, including rhabdoid tumors, epithelioid sarcoma, and chordoma. As tumor profiling has become more routine in clinical care, we investigated the relationship between SMARCB1 genetic variants identified by next-generation sequencing (NGS) and INI1 protein expression. Therapeutic approaches for INI1-deficient tumors are limited. Early reports suggest a potential role for immune checkpoint inhibition in these patients. Thus, we also investigated PD-L1 and CD8 expression in INI1-negative pediatric brain and solid tumors.

EXPERIMENTAL DESIGN

We performed immunohistochemistry (IHC) for INI1 and immune markers (PD-L1, CD8, and CD163) and NGS on tumor samples from 43 pediatric patients who had tumors with INI1 loss on previous IHC or SMARCB1 genomic alterations on prior somatic sequencing.

RESULTS

SMARCB1 two-copy deletions and inactivating mutations on NGS were associated with loss of INI1 protein expression. Single-copy deletion of SMARCB1 was not predictive of INI1 loss in tumor histologies not known to be INI1-deficient. In the 27 cases with INI1 loss and successful tumor sequencing, 24 (89%) had a SMARCB1 alteration detected. In addition, 47% (14/30) of the patients with INI1-negative tumors had a tumor specimen that was PD-L1 positive and 60% (18/30) had positive or rare CD8 staining. We report on 3 patients with INI1-negative tumors with evidence of disease control on immune checkpoint inhibitors.

CONCLUSIONS

A significant proportion of the INI1-negative tumors express PD-L1, and PD-L1 positivity was associated with extracranial tumor site. These results suggest that clinical trials of immune checkpoint inhibitors are warranted in INI1-negative pediatric cancers.

Local Stage Dependent Necessity of Radiation Therapy in Rhabdoid Tumors of the Kidney (RTK)

PURPOSE

Rhabdoid tumor of the kidney (RTK) is one of the most aggressive childhood renal tumors. Overall survival ranges from 22% to 47%. The indication for radiation therapy (RT) in usually very young patients is an ongoing discussion. Recent protocols recommend RT independent of local stage, the latter being a good discriminator in other childhood kidney tumors. In this study, we analyze the evidence for RT in regard to risk factors, including tumor stage.

METHODS AND MATERIALS

This study analyzed 58 patients with RTK from Austria, Switzerland, and Germany treated in the framework of 4 consecutive, prospective renal/rhabdoid tumor studies from 1991 to 2014. All treatment protocols included multimodality treatment, including high-intensity chemotherapy, surgery, and RT.

RESULTS

Local stage distribution was not applicable, I, II, and III in 1, 6, 11, and 40, respectively. Twenty-nine (50%) patients had stage IV disease at diagnosis. Thirty-seven patients (64%) achieved complete remission, and 49% (18/37) relapsed. Thirty-four patients (60%) patients had progressive disease and died, 17 had local disease, 10 had combined disease, and 7 had distant disease; 2 treatment-related deaths were reported (3%). Twenty-one patients received RT during first-line treatment, 18 of them to all involved sites. Eight of the 34 cases of progressive disease occurred in irradiated patients. The local failure rate of treated patients with local stage II or III disease was 29% (6/18) in patients irradiated to all sites compared with 68% (15/22) in nonirradiated patients. One of 6 stage I patients received RT, and 1 patient experienced distant relapse (2-year progression-free and overall survival both 83% ± 15%). Progression-free survival for local stage II and III disease treated with RT, adjusted for early relapse or treatment abandonment, was 67% ± 11%, compared with 15% ± 7% without RT (P < .0001).

CONCLUSION

The 68% local failure rate in nonirradiated patients underlines the importance of local treatment. Our experience supports the use of RT for local control in higher stage disease. In contrast, no local relapse in 6 local stage I patients, including 5 nonirradiated patients, suggests omission of RT in this favorable subset of usually infant patients with RTK.

Multimodal Management of Congenital Orbital Malignant Rhabdoid Tumor: Review of Literature and Report of a Rare Case

BACKGROUND

Malignant rhabdoid tumor (MRT) is a rare and aggressive tumor with a dismal prognosis. It commonly arises in the brain (65%), soft tissues (26%), and the kidney (9%). Primary orbital involvement is extremely rare. Although it has been mostly described in children below 2 years old, presentation at birth is sparsely reported.

OBSERVATION

We have described a case of congenital orbital MRT, who presented with rapidly progressive right-sided proptosis and was initially treated with subtotal resection and postoperative chemotherapy with ICE (Ifosfamide, Carboplatin, Etoposide) regimen. On local progression the child was treated with palliative radiotherapy (20 Gy) to the right orbit and second-line chemotherapy with VAC (Vincristine, Adriamycin, Cyclophosphamide) regimen. Unfortunately he died due to progressive disease 4 months after the initial diagnosis.

CONCLUSIONS

This report highlights the importance of awareness of orbital MRT as a differential diagnosis of rapidly progressing proptosis in the neonatal period. This tumor is often refractory to conventional multimodality treatment and more intensive and innovative treatment approaches are clearly needed in future.

Proteomic research in sarcomas - current status and future opportunities

Sarcomas are a rare group of mesenchymal cancers comprising over 70 different histological subtypes. For the majority of these diseases, the molecular understanding of the basis of their initiation and progression remains unclear. As such, limited clinical progress in prognosis or therapeutic regimens have been made over the past few decades. Proteomics techniques are being increasingly utilised in the field of sarcoma research. Proteomic research efforts have thus far focused on histological subtype characterisation for the improvement of biological understanding, as well as for the identification of candidate diagnostic, predictive, and prognostic biomarkers for use in clinic. However, the field itself is in its infancy, and none of these proteomic research findings have been translated into the clinic. In this review, we provide a brief overview of the proteomic strategies that have been employed in sarcoma research. We evaluate key proteomic studies concerning several rare and ultra-rare sarcoma subtypes including, gastrointestinal stromal tumours, osteosarcoma, liposarcoma, leiomyosarcoma, malignant rhabdoid tumours, Ewing sarcoma, myxofibrosarcoma, and alveolar soft part sarcoma. Consequently, we illustrate how routine implementation of proteomics within sarcoma research, integration of proteomics with other molecular profiling data, and incorporation of proteomics into clinical trial studies has the potential to propel the biological and clinical understanding of this group of complex rare cancers moving forward.

Malignant Rhabdoid Tumor of the Mediastinum: A Case Report and Literature Review

Malignant rhabdoid tumor (MRT) of the mediastinum is an aggressive tumor that is extremely rare. To date, only 24 cases of the mediastinal MRT have been reported in adults and 9 cases in the pediatric age group under the age of 18 years. We report a rare case of such tumor and review the literature on its clinical and imaging features as well as its treatment and prognostic outcomes.

Clinical and Prognostic Characteristics of 53 Cases of Extracranial Malignant Rhabdoid Tumor in Children. A Single-Institute Experience from 2007 to 2017

BACKGROUND

The aim of this study is to add to the current knowledge regarding extracranial malignant rhabdoid tumor (MRT), a rare and highly aggressive tumor that occurs most commonly in infants and young children.

PATIENTS AND METHODS

A retrospective medical record review was conducted on 53 patients with pathologically confirmed MRT in Beijing Children's Hospital between January 2007 and October 2017.

RESULTS

Fifty-three patients were diagnosed with MRT at a median age of 16 months, including 32 cases of malignant rhabdoid tumor of the kidney (MRTK) and 21 cases of extrarenal extracranial rhabdoid tumor (EERT). Fourteen (14/32, 43.75%) patients with MRTK and five (5/21, 23.81%) patients with EERT had metastases at diagnosis, and quite a few number of cases occurred tumor rupture (26.42%). Among the 53 patients, 40 (75.47%) patients died, 10 (18.87%) patients survived, and 3 patients (5.66%) were lost to follow-up. Among the 40 dead patients, 38 patients died from rapid progression of the disease or tumor recurrence, and 2 patients died of severe postoperative complications. Most of the recurrent or relapsed cases (94.11%) occurred within 8 months, with a median time of 76 days after diagnosis. The overall survival rates of 3 years and 5 years for the entire cohort were 23.71% and 18.44%, respectively. After survival analysis, it was clear that a younger age at diagnosis and distant stage patients had relatively poor outcomes. The effect of treatment was the most difficult to analyze because patients were not treated uniformly. Statistically significant differences in survival were noted among patients treated with standard chemotherapy, total resection, and radiotherapy.

CONCLUSION

Extracranial MRT is still a highly aggressive tumor in children. Younger patients and those suffering from metastatic disease were most likely to have a poor outcome because of rapid progression or recurrence of the tumor.

IMPLICATIONS FOR PRACTICE

This is the largest single-institutional report that investigates the clinical characteristics and outcomes of extracranial malignant rhabdoid tumor (MRT) in China. Our study showed that gross hematuria and tumor rupture were typical characteristics of malignant rhabdoid tumor of the kidney. After survival analysis, it was found that the advanced stage of the tumor and an age ≤12 months at diagnosis were significantly associated with poorer survival. Although extracranial MRT is still a highly aggressive tumor in children, multimodal treatment approach, including chemotherapy, surgery, and radiotherapy, should be employed for this disease.

Overall Survival of Primary Intracranial Atypical Teratoid Rhabdoid Tumor Following Multimodal Treatment: A Pooled Analysis of Individual Patient Data

No standard treatment protocol to guide the management of the primary central nervous system atypical teratoid rhabdoid tumors (ATRTs). To evaluate the efficacy of GTR (gross total resection), RT (radiotherapy), CCMT (conventional chemotherapy), or intensified chemotherapy (ICMT) and verify the optimal treatment strategy. A total of 501 cases (18 cases from our center and 483 cases from published literature) were eligible for analysis. Clinical characteristics were reviewed, and overall survival (OS) of each combined treatment modality was compared. These prior publication data were processed according to PRISMA guidelines. This study included 265 (52.9%) males and 216 (43.1%) females. The median age of the cohort was 2.2 years with 295 (58.9%) cases younger than 3 years. GTR was achieved in 217 (43.3%) patients. Initial adjuvant CCMT, CCMT plus intrathecal chemotherapy (ITCMT), CCMT plus high-dose chemotherapy (HDCMT), and CCMT plus ITCMT and HDCMT were administered in 228 (45.5%), 78 (15.6%), 55 (11.0%), and 24 (4.8%) patients, respectively. Radiotherapy (RT) was prescribed in 266 (53.1%) patients. Fewer patients younger than 3 years old received RT (21.9% vs 33.0%, p < 0.001, chi-square test). The OS of the entire cohort at 1, 3, and 5 years were 56.6, 35.9, and 30.8%, respectively. After adjusting for age and sex, GTR (HR 0.630; p < 0.001), RT (HR = 0.295; p < 0.001), CCMT (HR = 0.382; p < 0.001), and ICMT (HR = 0.209; p < 0.001) were independent prognostic factors. The 3-year OS of surgery alone, surgery plus CCMT, surgery plus RT, surgery plus ICMT, surgery plus CCMT and RT, and surgery plus ICMT and RT were 8.9, 13.4, 23.7, 37.4, 48.3, and 68.5%, respectively. When taking into consideration the extent of tumor resection (n = 462), GTR followed by RT, CCMT, intrathecal chemotherapy, and high-dose chemotherapy provided the best OS (5-year OS 88.2%). In younger children, adjuvant ICMT had a greater 3-year OS than adjuvant RT alone (34.0% vs 0%, p = .001). This study identified independent favorable predictors for OS of ATRTs and distinguished significantly different OS following various treatment modalities. If tolerable, intensive treatment with GTR followed by adjuvant RT and ICMT is recommended. Intensified CCMT could be an alternative to avoid radiological radiotoxicity for younger children CRD42018098841.

SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus): a clinicopathologic entity distinct from undifferentiated carcinoma

Small cell carcinoma of the ovary, hypercalcemic type is a rare, aggressive malignancy which usually occurs in young women and is characterized by mutations in SMARCA4, with few other alterations. We recently encountered uterine tumors with morphologic, immunohistochemical, and genetic similarities to small cell carcinoma of the ovary, hypercalcemic type. Herein we report the clinicopathologic and molecular features (using a targeted massively parallel sequencing [MPS] assay) of these tumors. The cases were diagnosed on cervical and endometrial biopsies (n = 2, 34, and 29 years) or hysterectomy and bilateral salpingo-oophorectomy (n = 3, 25, 33, and 58 years). The tumors were composed of sheets of large atypical epithelioid cells with prominent rhabdoid morphology, indistinguishable from the "large cell" variant of small cell carcinoma of the ovary, hypercalcemic type. In three cases, the ovaries were pathologically examined to exclude a primary ovarian malignancy. Immunohistochemically, four of four cases showed SMARCA4 loss, and were negative or only focally positive for keratins, EMA, and claudin-4. One of three cases was positive for WT-1. Targeted MPS was successfully performed on 4 of 5 tumors, and showed recurrent mutations in SMARCA4, with few other alterations. Of the cases diagnosed on hysterectomy, all had extensive lymphovascular invasion, extra-uterine spread, and marked infiltrative growth. These tumors were uniformly aggressive; all patients died of disease (median survival 7 months, range 1-43 months). We propose this entity be called "SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus)", a term which describes both the tumor's underlying molecular abnormality and its morphology. Its unique clinicopathologic and molecular features differentiate it from other related malignancies, including undifferentiated endometrial carcinoma, small cell carcinoma of the ovary (hypercalcemic type), and epithelioid sarcoma. We review and discuss previously reported "rhabdoid tumors of the uterus;" while they are a heterogenous group of tumors, some of them are likely examples of this entity. Correctly identifying cases of SMARCA4-deficient uterine sarcoma from histologic mimics is important as it may have prognostic, predictive, and germline implications.

Rhabdoid tumor of the liver: Report of 6 pediatric cases treated at a single institute

BACKGROUND

Rhabdoid tumors (RTs) of the liver are rare, aggressive and nonsecreting malignancies occurring mainly during the first year of life. Definition of RT relies on characteristic morphology and on the inactivation of the SMARCB1 tumor suppressor gene. The aim of this study was to analyze clinical data, treatments and outcomes in our patients.

PATIENTS AND METHODS

6 cases of patients treated in our institution for RT of the liver between January 2007 and January 2015 are reported. Variables examined included age at diagnosis, tumor stage, treatment and long-term survival.

RESULTS

Median age at diagnosis was 5months (range: 4-23). Normal for age serum AFP levels was observed in all patients. No patient presented with metastasis at diagnosis. The diagnosis of RT based on the loss of SMARCB1 was made early in 4 patients. The 2 others were initially diagnosed as nonsecreting hepatoblastomas. Median follow-up was 6years (range: 2-9). All patients received chemotherapy, with variable regimens depending on initial diagnosis, followed by surgical resection. Three patients (50%) died of disease. Two of them were mistaken for nonsecreting hepatoblastomas at diagnosis and had recurrence shortly after completion of treatment. The third one presented a cardiac right atrium thrombus. Three patients (50%) are long-term survivors; they received multimodal therapy including chemotherapy according to protocol EpSSG NRSTS consisting of doxorubicin and surgical removal of the tumor performed within 3months after diagnosis. One patient had adjuvant radiotherapy.

CONCLUSION

According to our results, search of SMARCB1 mutation or alternatively immunohistochemical assay for SMARCB1 in nonsecreting hepatoblastomas is mandatory to exclude RT. Chemotherapy according to EpSSG NRSTS protocol together with a surgical treatment seems justified to improve long-term survival.

TYPE OF STUDY

Retrospective study.

LEVEL OF EVIDENCE

Level IV.

Extraordinary disease-free survival in a rare malignant extrarenal rhabdoid tumor: a case report and review of the literature

BACKGROUND

Malignant extrarenal rhabdoid tumor of the gastrointestinal tract is rarely reported in the literature. It is characterized by poor prognosis and aggressive metastatic features. A literature review evidenced only 19 cases, with poor outcome.

CASE PRESENTATION

We report a case of a colonic "pure" malignant extrarenal rhabdoid tumor with metastatic nodes in a 65-year-old Caucasian man. He was treated surgically with no recurrence, no adjuvant chemotherapy, and with 4-year survival without disease at the time of the submission of this article.

CONCLUSIONS

We present an extraordinary case of long-term survival due to the extended surgical treatment. We believe that the absence of organ metastasis at presentation is a positive prognostic factor, although pathology confirmed node involvement (13/38 positive) on microscopy.