Atypical teratoid rhabdoid tumors: a population-based clinical outcomes study involving 174 patients from the Surveillance, Epidemiology, and End Results database (1973-2010)

Modeling human brain rhabdoid tumor by inactivating tumor suppressor genes in induced pluripotent stem cells

Atypical teratoid/rhabdoid tumor (ATRT) is a rare childhood malignancy that originates in the central nervous system. Over ninety-five percent of ATRT patients have biallelic inactivation of the tumor suppressor gene SMARCB1. ATRT has no standard treatment, and a major limiting factor in therapeutic development is the lack of reliable ATRT models. We employed CRISPR/Cas9 gene-editing technology to knock out SMARCB1 and TP53 genes in human episomal induced pluripotent stem cells (Epi-iPSCs), followed by brief neural induction, to generate an ATRT-like model. The dual knockout Epi-iPSCs retained their stemness with the capacity to differentiate into three germ layers. High expression of OCT4 and NANOG in neurally induced knockout spheroids was comparable to that in two ATRT cell lines. Beta-catenin protein expression was higher in SMARCB1-deficient cells and spheroids than in normal Epi-iPSC-derived spheroids. Nucleophosmin, Osteopontin, and Ki-67 proteins were also expressed by the SMARCB1-deficient spheroids. In summary, the tumor model resembled embryonal features of ATRT and expressed ATRT biomarkers at mRNA and protein levels. Ribociclib, PTC-209, and the combination of clofilium tosylate and pazopanib decreased the viability of the ATRT-like cells. This disease modeling scheme may enable the establishment of individualized tumor models with patient-specific mutations and facilitate high-throughput drug testing.

Sellar atypical teratoid/rhabdoid tumor in adults: survival analysis of treatment strategies. Illustrative case

BACKGROUND

Atypical teratoid/rhabdoid tumor (ATRT) is a rare, highly aggressive central nervous system tumor predominantly found in children. Limited information exists on ATRT in adults, posing challenges in diagnosis and treatment. This study presents the case of an adult patient with ATRT in the sellar region and explores the impact of different treatment regimens on patient survival.

OBSERVATIONS

A 60-year-old female with an ATRT underwent resection of the tumor, followed by adjuvant chemoradiotherapy. Molecular genetic analysis revealed compound heterozygous SMARCB1 point mutations. Survival analysis was performed on previously published adult ATRT cases, comparing treatment approaches. The cohort's overall median survival was 6 months, with patients receiving combined chemoradiotherapy showing the longest median survival of 23.5 months. Statistical analysis demonstrated a significant difference in survival between patients treated with surgery alone and those receiving surgery followed by chemoradiotherapy (p < 0.001). However, no significant difference was observed between patients treated with surgery alone and those with postoperative radiotherapy (p = 0.105).

LESSONS

Early initiation of adjuvant chemoradiotherapy following surgery improves survival outcomes in adult patients with ATRT. Because of limited data on standardized treatment protocols for adults with ATRT, further research and larger-scale studies are needed to establish effective treatment guidelines for this population.

MRI features of pediatric atypical teratoid rhabdoid tumors and medulloblastomas of the posterior fossa

BACKGROUND

Atypical teratoid rhabdoid tumor (AT/RT) occurs at a younger age and is associated with a worse prognosis than medulloblastoma; however, these two tumor entities are mostly indistinguishable on neuroimaging. The aim of our study was to differentiate AT/RT and medulloblastoma based on their clinical and MRI features to enhance treatment planning and outcome prediction.

METHODS

From 2005-2021, we retrospectively enrolled 16 patients with histopathologically diagnosed AT/RT and 57 patients with medulloblastoma at our institute. We evaluated their clinical data and MRI findings, including lesion signals, intratumoral morphologies, and peritumoral/distal involvement.

RESULTS

The age of children with AT/RT was younger than that of children with medulloblastoma (2.8 ± 4.9 [0-17] vs. 6.5 ± 4.0 [0-18], p < 0.001), and the overall survival rate was lower (21.4% vs. 66.0%, p = 0.005). Regarding lesion signals on MRI, AT/RT had a lower ADC_min (cutoff value ≤544.7 × 10^-6  mm² /s, p < 0.001), a lower ADC ratio (cutoff value ≤0.705, p < 0.001), and a higher DWI ratio (cutoff value ≥1.595, p < 0.001) than medulloblastoma. Regarding intratumoral morphology, the "tumor central vein sign" was mostly exclusive to medulloblastoma (24/57, 42.1%; AT/RT 1/16, 6.3%; p = 0.007). Regarding peritumoral invasion on T2WI, AT/RT was more prone to invasion of the brainstem (p < 0.001) and middle cerebellar peduncle (p < 0.001) than medulloblastoma.

CONCLUSIONS

MRI findings of a lower ADC value, more peritumoral invasion, and absence of the "tumor central vein sign" may be helpful to differentiate AT/RT from medulloblastoma. These distinct MRI findings together with the younger age of AT/RT patients may explain the worse outcomes in AT/RT patients.

Embryonal Tumors of the Central Nervous System with Multilayered Rosettes and Atypical Teratoid/Rhabdoid Tumors

The 2016 WHO classification of tumors of the central nervous system affected importantly the group of CNS embryonal tumors. Molecular analysis on methylome, genome, and transcriptome levels allowed better classification, identification of specific molecular hallmarks of the different subtypes of CNS embryonal tumors, and their more precise diagnosis. Routine application of appropriate molecular testing and standardized reporting are of pivotal importance for adequate prognosis and treatment, but also for epidemiology studies and search for efficient targeted therapies. As a result of this approach, the term primitive neuroectodermal tumor-PNET was removed and a new clinic-pathological entity was introduced-Embryonal tumor with multilayered rosettes (ETMR). The group of CNS embryonal tumors include also medulloblastoma, medulloepithelioma, CNS neuroblastoma, CNS ganglioneuroblastoma, atypical teratoid/rhabdoid tumor (ATRT) and their subtypes. This chapter will focus mainly on ETMR and ATRT. Embryonal tumors with multilayered rosettes and the atypical teratoid/rhabdoid tumors are undifferentiated or poorly differentiated tumors of the nervous system that originate from primitive brain cells, develop exclusively in childhood or adolescence, and are characterized by a high degree of malignancy, aggressive evolution and a tendency to metastasize to the cerebrospinal fluid. Their clinical presentation is similar to other malignant, intracranial, neoplastic lesions and depends mainly on the localization of the tumor, the rise of the intracranial pressure, and eventually the obstruction of the cerebrospinal fluid pathways. The MRI image characteristics of these tumors are largely overlappingintra-axial, hypercellular, heterogeneous tumors, frequently with intratumoral necrosis and/or hemorrhages. Treatment options for ETMR and ATRT are very restricted. Surgery can seldom achieve radical excision. The rarity of the disease hampers the establishment of a chemotherapy protocol and the usual age of the patients limits severely the application of radiotherapy as a therapeutic option. Consequently, the prognosis of these undifferentiated, malignant, aggressive tumors remains dismal with a 5-year survival between 0 and 30%.

Atypical teratoid rhabdoid tumor with intratumoral advancement: significance of active surgical approach in long-term disease (109 months) with metastatic cascade

The article presents a clinical case of atypical teratoid rhabdoid tumor with one of the longest catamnesis described in literature (109 months) and high quality of life. first, a giant tumor of the frontal lobe with advancement into a lateral ventricle was found in a female patient and totally removed. It was histologically diagnosed as primitive neuroectodermal tumor. Combination treatment consisting of radiotherapy, high-dose polychemotherapy and cellular immunotherapy including intrathecal therapy led to 4-year recurrence-free period. Recurrence of the tumor was resected. The period of the 2nd remission was 34 months. Subsequently, multistage metastasis of the tumor through cerebrospinal fluid tracts of the brain and spinal cord was observed. Twice microsurgical treatment with removal of symptomatic metastases in ventricles Iv and III was performed. In repeat morphological examinations, the tumor was verified as atypical teratoid rhabdoid tumor. The presented clinical case shows the role of active surgical tactics in effective long-term combination treatment of this severe pathology.

Sellar Atypical Teratoid/Rhabdoid Tumors (AT/RT): A Systematic Review and Case Illustration

Introduction: Atypical Teratoid/Rhabdoid tumors are rare, highly malignant tumors in adults, with a median survival of 20 months. We report a case of a sellar atypical teratoid/rhabdoid tumor in a 70-year-old female treated with intraventricular chemotherapy, followed by a systematic review of the current management of sellar AT/RTs.

Methods: A comprehensive systematic literature search was conducted on Web of Science, Scopus, and PubMed Central using the key terms “sellar” and “atypical teratoid/rhabdoid tumors”, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data, including patient demographics, histology, treatments, and overall survival were extracted and analyzed. Kaplan-Meier survival curves and log-rank analysis were used to compare survival outcomes between different treatment regimens.

Results: Our literature search disclosed 123 publications. After prespecified exclusions, 41 patients with sellar AT/RT from 30 manuscripts were identified, and 38 were included in the final analysis. Including our patient, the median age was 44 (range: 20-70) with a substantial female predominance (94.7%). Collectively, patients who received combined chemoradiation therapy had a significantly increased overall survival compared to those who received single modality or no adjuvant therapies (median OS 27 vs. 1.25 months; p=0.0052).

Conclusion: Atypical teratoid/rhabdoid tumor in the sellar region carries a poor prognosis. Adjuvant chemotherapy and radiation therapy were associated with significantly increased overall survival. Early consideration of neuro-oncology and radiation-oncology referral and management is likely beneficial in this patient population. Intrathecal chemotherapy is a treatment modality that requires further exploration given the limited options and current dismal prognosis of adult sellar AT/RT.

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.

Atypical Teratoid Rhabdoid Tumor: A Possible Oriented Female Pathology?

Atypical teratoid rhabdoid tumor is a rare lesion that occurs mainly in children can be supratentorial or infratentorial and it accounts for 1-2% of pediatric brain tumors and over 10% of central nervous system (CNS) tumors in infants, with a male preponderance up to 3 years of age, more than 50% of these occur in the cerebellum. In this report we describe four new cases of sellar AT/RTs underwent endoscopic endonasal approach and different adjuvant therapies. Our aim is to report the clinical, radiological and pathological features of these rare lesions, focusing on the possibility to perform an early diagnosis and appropriate therapeutic strategy.

Atypical Teratoid Rhabdoid Tumours Are Susceptible to Panobinostat-Mediated Differentiation Therapy

Simple Summary

Atypical teratoid rhabdoid tumour (ATRT) is an aggressive undifferentiated malignancy of the central nervous system in children. A defining feature of ATRT is the loss of the SMARCB1 gene that is essential for regulating gene expression required for normal developmental processes. We show that treatment of human ATRT cell models with the histone deacetylate inhibitor, panobinostat, inhibits tumour growth, reactivates the expression of developmental genes, and drives neuronal differentiation. These results demonstrate the therapeutic potential of panobinostat for the treatment of ATRT.

Abstract

Atypical teratoid rhabdoid tumour (ATRT) is a rare but highly aggressive undifferentiated solid tumour arising in the central nervous system and predominantly affecting infants and young children. ATRT is exclusively characterized by the inactivation of SMARCB1, a member of the SWI/SNF chromatin remodelling complex that is essential for the regulation of large sets of genes required for normal development and differentiation. Histone deacetylase inhibitors (HDACi) are a promising anticancer therapy and are able to mimic the normal acetylation functions of SMARCB1 in SMARCB1-deficient cells and drive multilineage differentiation in extracranial rhabdoid tumours. However, the potential efficacy of HDACi in ATRT is unknown. Here, we show that human ATRT cells are highly responsive to the HDACi panobinostat and that sustained treatment leads to growth arrest, increased cell senescence, decreased clonogenicity and induction of a neurogenesis gene-expression profile. Furthermore, in an orthotopic ATRT xenograft model, continuous panobinostat treatment inhibits tumour growth, increases survival and drives neuronal differentiation as shown by the expression of the neuronal marker, TUJ1. Collectively, this preclinical study supports the therapeutic potential of panobinostat-mediated differentiation therapy for ATRT.

Imaging of brain tumors in children: the basics-a narrative review

Primary pediatric brain tumors comprise a broad group of neoplasm subtypes that can be categorized based on their histological and molecular features according to the 2016 World Health Organization (WHO) classification of central nervous system (CNS) tumors. The majority of the pediatric brain tumors demonstrate a singular preference for this age group and have a unique molecular profile. The separation of certain tumor entities, including different types of embryonal tumors, low-grade gliomas, and high-grade gliomas, may have a significant impact by guiding appropriate treatment for these children and potentially changing their outcomes. Currently, the focus of the imaging diagnostic studies is to follow the molecular updates, searching for potential imaging patterns that translate this information in molecular profile results, therefore helping the final diagnosis. Due to the high impact of accurate diagnosis in this context, the scientific community has presented extensive research on imaging pediatric tumors in recent years. This article summarizes the key characteristics of the imaging features of the most common primary childhood brain tumors, categorizing them according to the recent WHO classification update, which is based on each of their molecular profiles. The purpose of this review article is to familiarize radiologists with their key imaging features and thereby improve diagnostic accuracy.

Atypical Teratoid Rhabdoid Tumors (ATRT): King Faisal Specialist Hospital and Research Centre experience

Background

Atypical teratoid rhabdoid tumor is an uncommon aggressive central nervous system tumor. All retrospective series have shown a short mean overall survival rate. Considering the rarity of the disease, few prospective clinical trials addressed treatment recommendations for such aggressive tumors, and consequently no definitive treatment guidelines have been established. In this study, we are reviewing our experience in treating atypical teratoid rhabdoid tumor patients.

Methods

We reviewed the medical charts of 43 patients with atypical teratoid rhabdoid tumor who were treated in King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia, between 1996 and 2013. We evaluated the overall survival rate and the influence of different clinical features and treatment protocols on survival.

Results

The median overall survival time was 16.9 months (95% Confidence Interval, 5.2–32.9 months) with an estimated 2- and 5-year overall survival of 41.9% ± 9.6 and 27.9% ± 9.2, respectively. Patients receiving trimodal treatment (surgery, chemotherapy, and radiotherapy) exhibited significantly better median overall survival time compared to their counterparts (P value < .001).

Conclusions

Atypical teratoid rhabdoid tumor is rare and aggressive central nervous system tumor. Despite the limitations of the study, our results support several of clinical practice development. Utilization of postoperative radiotherapy and the adoption of trimodal therapy are associated with significant improvement of median survival. Prompt management with aggressive trimodal therapy should be the standard for future treatment protocols.

Magnetic resonance imaging surrogates of molecular subgroups in atypical teratoid/rhabdoid tumor

Background

Recently, 3 molecular subgroups of atypical teratoid/rhabdoid tumor (ATRT) were identified, but little is known of their clinical and magnetic resonance imaging (MRI) characteristics.

Methods

A total of 43 patients with known molecular subgroup status (ATRT-sonic hedgehog [SHH], n = 17; ATRT-tyrosine [TYR], n = 16; ATRT-myelocytomatosis oncogene [MYC], n = 10) were retrieved from the EU-RHAB Registry and analyzed for clinical and MRI features.

Results

On MRI review, differences in preferential tumor location were confirmed, with ATRT-TYR being predominantly located infratentorially (P < 0.05). Peritumoral edema was more pronounced in ATRT-MYC compared with ATRT-SHH (P < 0.05) and ATRT-TYR (P < 0.05). Conversely, peripheral tumor cysts were found more frequently in ATRT-SHH (71%) and ATRT-TYR (94%) compared with ATRT-MYC (40%, P < 0.05). Contrast enhancement was absent in 29% of ATRT-SHH (0% of ATRT-TYR; 10% of ATRT-MYC; P < 0.05), and there was a trend toward strong contrast enhancement in ATRT-TYR and ATRT-MYC. We found the characteristic (bandlike) enhancement in 28% of ATRT as well as restricted diffusion in the majority of tumors. A midline/off-midline location in the posterior fossa was also not subgroup specific. Visible meningeal spread (M2) at diagnosis was rare throughout all subgroups.

Conclusion

These exploratory findings suggest that MRI features vary across the 3 molecular subgroups of ATRT. Within future prospective trials, MRI may aid diagnosis and treatment stratification.

Case-based review: atypical teratoid/rhabdoid tumor

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare CNS cancer that typically occurs in children younger than 3 years of age. Histologically, AT/RTs are embryonal tumors that contain a rhabdoid component as well as areas with primitive neuroectodermal, mesenchymal, and epithelial features. Compared to other CNS tumors of childhood, AT/RTs are characterized by their rapid growth, short symptomatic prodrome, and large size upon presentation, often leading to brain compression and intracranial hypertension requiring urgent intervention. For decades, the mainstay of care has been a combination of maximal safe surgical resection followed by adjuvant chemotherapy and radiotherapy. Despite advances in each of these modalities, the relative paucity of data on these tumors, their inherently aggressive course, and a lack of molecular data have limited advances in treatment over the past 3 decades. Recent large-scale, multicenter interdisciplinary studies, however, have significantly advanced our understanding of the molecular pathogenesis of these tumors. Multiple clinical trials testing molecularly targeted therapies are underway, offering hope for patients with AT/RT and their families.

Pediatric Suprasellar Atypical Teratoid Rhabdoid Tumor Arising from the Third Ventricle: A Rare Tumor at a Very Rare Location

Atypical teratoid rhabdoid tumor (ATRT) is a rare, highly malignant tumor of the central nervous system, commonly affecting children below 3 years of age, with around 300 cases reported in the literature. Suprasellar area is a very rare location for such tumor in the pediatric population, with technical difficulties in complete excision. Third ventricular ATRT is very rare. Here, we report the case of a 2-year-old male child who presented with lethargy and vomiting. He had features of raised intracranial pressure with reduced vision in both eyes. Magnetic resonance imaging of the brain revealed a heterogeneously enhancing lobulated giant lesion in the suprasellar location, occupying the third ventricle and hypothalamus with encasement of both carotids. He underwent pericoronal parasagittal craniotomy, interhemispheric transcallosal interforniceal approach and gross total excision of the lesion. Postoperatively, the child had altered sensorium and diabetes insipidus, both of which recovered over a span of 10 days. Histopathological examination of the specimen was consistent with the diagnosis of World Health Organization Grade IV ATRT. In spite of all our efforts, he succumbed to his illness 5 months postoperatively.

Atypical Teratoid Rhabdoid Tumor: Two Case Reports and an Analysis of Adult Cases with Implications for Pathophysiology and Treatment

We present the first quantitative analysis of atypical teratoid rhabdoid tumors (ATRT) in adults, including two patients from our own institutions. These are of interest as one occurred during pregnancy and one is a long-term survivor. Our review of pathological findings of 50 reported cases of adult ATRT leads us to propose a solely ectodermal origin for the tumor and that epithelial–mesenchymal transition (EMT) is a defining feature. Thus, the term ATRT may be misleading. Our review of clinical findings shows that ATRT tends to originate in mid-line structures adjacent to the CSF, leading to a high rate of leptomeningeal dissemination. Thus, we hypothesize that residual undifferentiated ectoderm in the circumventricular organs, particularly the pituitary and pineal glands, is the most common origin for these tumors. We note that if growth is not arrested soon after diagnosis, or after the first relapse/progression, death is almost universal. While typically rapidly fatal (as in our first case), long-term remission is possible (as in our second). Significant predictors of prognosis were the extent of resection and the use of chemotherapy. Glial differentiation (GFAP staining) was strongly associated with leptomeningeal metastases (chi-squared p = 0.02) and both predicted markedly worse outcomes. Clinical trials including adults are rare. ATRT is primarily a disease of infancy and radiotherapy is generally avoided in those aged less than 3 years old. Treatment options in adults differ from infants in that cranio-spinal irradiation is a viable adjunct to systemic chemotherapy in the adult population. Given the grave prognosis, this combined approach appears reasonable. As effective chemotherapy is likely to cause myelosuppression, we recommend that stem-cell rescue be available locally.

Embryonal tumors in Canadian children less than 36 months of age: results from the Canadian Pediatric Brain Tumor Consortium (CPBTC)

Embryonal tumors are a heterogeneous group of central nervous system (CNS) tumors whose subgroups have varying incidence and outcome. Despite these differences, they are often grouped as a single entity for study purposes. To date, there are no Canadian multi-institutional studies examining the incidence and outcome of all embryonal subtypes. The current study is an observational study reviewing embryonal tumors in all patients less than 36 months of age diagnosed with a CNS tumor in Canada from 1990 to 2005. Embryonal tumors accounted for 26.9% of all CNS tumors. Medulloblastomas were the highest proportion of the embryonal tumors at 61.5%. Atypical teratoid/rhabdoid tumors (AT/RT) had the second highest proportion of embryonal tumors at 18%. The proportion of primitive neuroectodermal tumors (PNET) was 16%, with 2.6 and 1.9% for congenital medulloepithelioma and ependymoblastoma tumors, respectively. AT/RT and PNET were more common in younger age groups. Medulloblastoma became more prevalent with increasing age, with its highest prevalence in the 25 to 36 month age group. Survival rates for our Canadian population at 18 and 24 months were 0.74 and 0.68 for medulloblastoma, 0.64 and 0.60 for PNET, and 0.36 and 0.29 for AT/RT, respectively. Overall, our data are comparable with published international rates for embryonal tumors. These incidence and outcome figures can guide future research into these rare tumors.

Molecular analyses reveal close similarities between small cell carcinoma of the ovary, hypercalcemic type and atypical teratoid/rhabdoid tumor

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is the most common undifferentiated ovarian malignancy diagnosed in women under age 40. We and others recently determined that germline and/or somatic deleterious mutations in SMARCA4 characterize SCCOHT. Alterations in this gene, or the related SWI/SNF chromatin remodeling gene SMARCB1, have been previously reported in atypical teratoid/rhabdoid tumors (ATRTs) and malignant rhabdoid tumors (MRTs). To further describe the somatic landscape of SCCOHT, we performed whole exome sequencing on 14 tumors and their matched normal tissues and compared their genomic alterations with those in ATRT and ovarian high grade serous carcinoma (HGSC). We confirmed that SMARCA4 is the only recurrently mutated gene in SCCOHT, and show that recurrent allelic imbalance is observed exclusively on chromosome 19p, where SMARCA4 resides. By comparing genomic alterations between SCCOHT, ATRT and HGSC, we demonstrate that SCCOHTs, like ATRTs, have a remarkably simple genome and harbor significantly fewer somatic protein-coding mutations and chromosomal alterations than HGSC. Furthermore, a comparison of global DNA methylation profiles of 45 SCCOHTs, 65 ATRTs, and 92 HGSCs demonstrates a strong epigenetic correlation between SCCOHT and ATRT. Our results further confirm that the genomic and epigenomic signatures of SCCOHT are more similar to those of ATRT than HGSC, supporting our previous hypothesis that SCCOHT is a rhabdoid tumor and should be renamed MRT of the ovary. Furthermore, we conclude that SMARCA4 inactivation is the main cause of SCCOHT, and that new distinct therapeutic approaches should be developed to specifically target this devastating tumor.

The molecular pathogenesis of schwannomatosis, a paradigm for the co-involvement of multiple tumour suppressor genes in tumorigenesis

Schwannomatosis is characterized by the predisposition to develop multiple schwannomas and, less commonly, meningiomas. Despite the clinical overlap with neurofibromatosis type 2 (NF2), schwannomatosis is not caused by germline NF2 gene mutations. Instead, germline mutations of either the SMARCB1 or LZTR1 tumour suppressor genes have been identified in 86% of familial and 40% of sporadic schwannomatosis patients. In contrast to patients with rhabdoid tumours, which are due to complete loss-of-function SMARCB1 mutations, individuals with schwannomatosis harbour predominantly hypomorphic SMARCB1 mutations which give rise to the synthesis of mutant proteins with residual function that do not cause rhabdoid tumours. Although biallelic mutations of SMARCB1 or LZTR1 have been detected in the tumours of patients with schwannomatosis, the classical two-hit model of tumorigenesis is insufficient to account for schwannoma growth, since NF2 is also frequently inactivated in these tumours. Consequently, tumorigenesis in schwannomatosis must involve the mutation of at least two different tumour suppressor genes, an occurrence frequently mediated by loss of heterozygosity of large parts of chromosome 22q harbouring not only SMARCB1 and LZTR1 but also NF2. Thus, schwannomatosis is paradigmatic for a tumour predisposition syndrome caused by the concomitant mutational inactivation of two or more tumour suppressor genes. This review provides an overview of current models of tumorigenesis and mutational patterns underlying schwannomatosis that will ultimately help to explain the complex clinical presentation of this rare disease.

The Surveillance, Epidemiology, and End Results (SEER) Program and Pathology: Toward Strengthening the Critical Relationship

The Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute collects data on cancer diagnoses, treatment, and survival for approximately 30% of the United States (US) population. To reflect advances in research and oncology practice, approaches to cancer control are evolving from simply enumerating the development of cancers by organ site in populations to including monitoring of cancer occurrence by histopathologic and molecular subtype, as defined by driver mutations and other alterations. SEER is an important population-based resource for understanding the implications of pathology diagnoses across demographic groups, geographic regions, and time and provides unique insights into the practice of oncology in the US that are not attainable from other sources. It provides incidence, survival, and mortality data for histopathologic cancer subtypes, and data by molecular subtyping are expanding. The program is developing systems to capture additional biomarker data, results from special populations, and expand biospecimen banking to enable cutting-edge cancer research and oncology practice. Pathology has always been central and critical to the effectiveness of SEER, and strengthening this relationship in this modern era of cancer diagnosis could be mutually beneficial. Achieving this goal requires close interactions between pathologists and the SEER program. This review provides a brief overview of SEER, focuses on facets relevant to pathology practice and research, and highlights the opportunities and challenges for pathologists to benefit from and enhance the value of SEER data.

Long-term survival following additive radiotherapy in patients with atypical teratoid rhabdoid tumors

BACKGROUND

Atypical teratoid rhabdoid tumor (ATRT) is a highly aggressive disease of embryonic origin accounting for <5% of all pediatric central nervous system (CNS) tumors.

PATIENTS AND METHODS

We describe a series of five cases of CNS ATRT. The first three patients underwent subtotal tumor resection. Gross total resection of the tumor was achieved in the fourth and fifth patients. Only 4 patients received chemotherapy, whereas all 5 patients received additive radiotherapy (RT). The latter included three dimensional (3D) conformal RT or intensity modulated RT (IMRT) with a median dose of 54 Gy (range 50.4-59.0 Gy) applied in daily fractions of 1.8 Gy. The median interval between surgery and RT was 5 months (range 2-11 months).

RESULTS

Two months after completion of RT, 4 patients had achieved complete radiologic remission. The median event-free survival period was 46 months (range 10-90 months). However, the first patient died 17 months after developing an out-of-field recurrence. The third patient developed a recurrence 11 months after salvage RT. The other 3 patients (cases 2, 4, and 5) remain alive with no evidence of disease 59, 46 and 90 months after therapy, respectively.

CONCLUSION

Overall, the 5 patients survived for a median of 48 months (range 25-90 months) from the time of initial diagnosis and they tolerated the RT well, without severe acute or late onset toxicities. The results imply a potential survival gain after irradiation at acceptable toxicity level.

The influence of clinical and genetic factors on patient outcome in small cell carcinoma of the ovary, hypercalcemic type

OBJECTIVE

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is an aggressive tumor, with long term survival at ~30% in early stage disease. SCCOHT is caused by germline and somatic SMARCA4 mutations, but the effect of the mutation type on patients remains unknown. Furthermore, the rarity of SCCOHT has resulted in varied treatment, with no standardized protocols. We analyzed 293 cases to determine the effect of treatment modalities and SMARCA4 mutations on patient diagnosis and outcome.

METHODS

In 293 SCCOHT patients we collected information on age and stage at diagnosis, treatment modality (surgery, chemotherapy, radiotherapy, and/or high-dose chemotherapy with autologous stem cell rescue (HDC-aSCR)), SMARCA4 mutation origin (germline/somatic), and overall survival. Cox analysis and log-rank tests were performed on 257 cases with available survival data.

RESULTS

The strongest prognostic factors were stage at diagnosis (p=2.72e-15) and treatment modality (p=3.87e-13). For FIGO stages II-IV, 5-year survival was 71% for patients who received HDC-aSCR, compared to 25% in patients who received conventional chemotherapy alone following surgery (p=0.002). Patients aged ≥40 had a worse outcome than younger patients (p=0.04). Twenty-six of 60 tested patients carried a germline SMARCA4 mutation, including all patients diagnosed <15years; carriers presented at a younger age than non-carriers (p=0.02).

CONCLUSIONS

Stage at diagnosis is the most significant prognostic factor in SCCOHT and consolidation with HDC-aSCR may provide the best opportunity for long-term survival. The large fraction of SMARCA4 germline mutations carriers warrants genetic counseling for all patients.

Primary atypical teratoid/rhabdoid tumor of the spine in an adult patient

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) is an aggressive neoplasm of the central nervous system that generally arises intracranially in patients under 2 years of age. Primary spinal AT/RT in an adult is rare.

CASE DESCRIPTION

A 23-year-old female presented with left lower extremity sciatica attributed to a magnetic resonance imaging (MRI)-documented intradural mass between L2 and L4. The lesion was biopsied (was unresectable) and treated with high-dose chemotherapy (methotrexate, vincristine, cyclophosphamide, etoposide, and cisplatin) with autologous hematopoietic stem cells rescue, followed by 2 months of radiation therapy (36 Gy to craniospinal axis, 20 Gy to lumbar region) with concurrent temozolomide; the latter was discontinued after 3 weeks due to myelosuppression. Tumor relapsed 1 year later at C7-T1 level. She was started on oral metronomic therapy, and bevacizumab was added 2 months later. Three months later, a cervical MRI showed progression of the tumor, along with new lesions in the thoracic/lumbar spine plus intracranial punctate nodular tumors. Following resection of the C7/T1 lesion, she was started on palliative alisertib; a month later, a cranial computed tomography showed progression of her disease with hydrocephalus. Treatment was discontinued, and she expired 12 months after initial diagnosis.

CONCLUSION

Primary spinal AT/RT in the adult patient is rare. The pathology is associated with early recurrence and a poor prognosis. Although potential benefits of metronomic chemotherapy and alisertib have been reported, the patient in this study did not favorably respond to these modalities.