Search Results (7)

Objectives: Atypical teratoid/rhabdoid tumors (ATRTs) are rare, malignant central nervous system (CNS) neoplasms that predominantly affect infants and young children. While ATRT arises throughout the CNS, its extracranial counterpart, malignant rhabdoid tumor, occurs in other organs. A single-institutional cohort is reviewed to map anatomic distribution of pediatric ATRTs and to integrate a literature review to contextualize ATRT histogenesis from anatomical and embryological perspectives. Methods: A retrospective review was conducted on a cohort of 50 pediatric patients with ATRT treated over 20 years. Demographic, surgical, and neuroimaging data were correlated to define tumor location, extent, and compartmental involvement. A focused literature review synthesized molecular subclassifications and proposed cells of origin/cytogenesis. Results: Of the 50 ATRTs, 18 (36%) were infratentorial, 15 (30%) supratentorial, 11 (22%) in the pineal region, and 6 (12%) in the spinal compartment. Among infratentorial tumors, 10 were centered in the fourth ventricle, with or without extension into the cerebellopontine angle (CPA) cistern; the remainder arose in the CPA. Among ATRTs of the cerebral hemispheres, 3 showed bi-hemispheric involvement crossing the falx cerebri. ATRTs of the pineal region predominantly originated from the superior medullary velum. These topographic data were corelated with embryological and molecular information available in the literature. Conclusions: ATRTs arise across diverse neuroanatomical compartments—including intraparenchymal, intraventricular, extra-axial, and extradural sites—underscoring biological heterogeneity. Inactivation of SMARCB1 is the defining molecular event and principal oncogenic driver, although the upstream mechanisms precipitating these alterations remain incompletely resolved. Molecular subgroups—ATRT-TYR, ATRT-SHH, and ATRT-MYC—display distinct age distributions and anatomic predilections, implicating developmental context in tumor initiation. The characteristic cellular admixture of rhabdoid cells with mesenchymal and/or epithelial differentiation, together with intra- and extra-axial and occasional extradural presentations, supports a model in which at least a subset of ATRTs may originate from neural crest-derived lineages, despite little or no neural crest contribution to brain parenchyma development. Neural plate border progenitors with bipotent features represent a plausible intraparenchymal cell of origin. Definitive resolution of these origins and the mechanisms of SMARCB1 disruption will require integrated approaches. Further investigations are warranted to clarify these mechanisms. Full article

Atypical Teratoid/Rhabdoid Tumor (AT/RT) is a highly aggressive neoplasm of the central nervous system (CNS), most commonly affecting infants and young children. Originally recognized as a distinct entity following cytogenetic identification of monosomy 22 in renal Rhabdoid Tumors, AT/RT now encompasses CNS tumors characterized by SMARCB1 (INI-1) or SMARCA4 (BRG-1) alterations within the SWI/SNF chromatin-remodeling complex. The integration of immunohistochemical markers with advanced molecular diagnostics—including next-generation sequencing, DNA methylation profiling, and gene enrichment analyses—has facilitated robust tumor classification and the identification of three molecular subgroups: TYR, SHH, and MYC. Despite its distinctive histopathologic features, AT/RT remains diagnostically challenging in adolescent and adult populations due to age-related bias and potential morphologic heterogeneity. Differential considerations, including epithelioid sarcoma, poorly differentiated chordoma, CRINET, choroid plexus carcinoma, and rare composite tumors, further complicate the diagnostic landscape. A comprehensive, multimodal diagnostic approach combining histologic, immunophenotypic, and molecular data is essential to accurately identify AT/RT and guide clinical management, particularly in diagnostically ambiguous or atypical cases. Full article

Multiple Endocrine Neoplasia Type 1 (MEN1) is an autosomal dominant disorder commonly associated with tumor development in the parathyroid glands, pancreas, and pituitary gland. While pituitary adenomas are frequently observed in MEN1 patients, the presence of additional tumors within the pituitary gland is unusual. Moreover, the co-occurrence of a pituitary adenoma with an atypical teratoid/rhabdoid tumor (ATRT) has not been previously documented. ATRT is a rare, aggressive neoplasm predominantly affecting young children and is typically associated with inactivating mutations in the SMARCB1 or SMARCA4 tumor suppressor genes. These mutations result in uncontrolled cellular proliferation, which underlies the malignancy’s rapid progression. In adults, ATRT is exceedingly rare, making this case particularly noteworthy for its uniqueness in both tumor type and patient demographics. ATRTs are now classified into three molecular subgroups—MYC, SHH, and TYR—each with distinct epigenetic and clinical features, further refining diagnostic and prognostic assessments. In this case report, we describe a case of a female patient with MEN1 who experienced several recurrences of pituitary adenoma, ultimately necessitating surgical resection. Detailed pathological evaluation of the resected tissue revealed two distinct neoplasms within the pituitary gland: one typical of a pituitary adenoma, and the other confirmed as ATRT. The diagnosis of ATRT was established through extensive workup including immunohistochemical analysis, next-generation sequencing and methylation profiling, which served as essential tools in distinguishing ATRT from other potential differential diagnoses. This case illustrates the complex diagnostic journey and challenges encountered in identifying ATRT in the context of MEN1, underscoring the importance of using advanced molecular and immunohistochemical techniques in atypical presentations. Furthermore, it expands the understanding of potential tumor associations within MEN1, providing insight for pathologists and clinicians into the rare possibility of concurrent tumors in addition to pituitary adenoma in MEN1 patients. Raising awareness of such co-occurrences could prompt earlier diagnostic considerations by refining the differential diagnosis in patients with MEN1 presenting with unusual tumor types. Full article

Background: Atypical teratoid rhabdoid tumor (ATRT) is a highly aggressive, rare pediatric central nervous system malignancy. Prognostic factors for optimizing risk stratification and management in a large uniformly treated cohort are lacking. Methods: We conducted a single-center retrospective cohort study analyzing clinical and outcome data for 100 newly diagnosed ATRT patients aged <18 years treated at the Children’s Cancer Hospital, Egypt, from 2008 to 2022. They were treated uniformly as per the Dana-Farber Cancer Institute modified IRS-III protocol. Molecular subgroups (MYC, SHH, and TYR) were determined via a DNA methylation array for patients who had sufficient DNA material available for the methylation analysis. Treatment toxicities were graded per the Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Results: The median age at diagnosis was 1.88 years (IQR 0.99, 3.01); 28% were under 1 year of age, 45% were between 1 and 3 years old, and 26% were above 3 years of age. At diagnosis, 39% of patients had metastatic disease. A total of 60% of patients had gross residual disease following surgical excision. In multivariable analysis, age < 1 year and metastatic disease had a significant impact on event-free survival (EFS) (p = 0.047 and p = 0.002, respectively); however, only metastatic disease had a significantly negative effect on overall survival (OS) and cumulative incidence of relapse (CIR) (p = 0.002 for OS and p < 0.001 for CIR). DNA methylation was performed for 69 patients who were classified as having a TYR (n = 13), SHH (n = 34), MYC (n = 17), or non-ATRT diagnosis (n = 5). In the cohort of the 64 patients with ATRT defined by methylation, no significant survival differences were observed. Treatment-related deaths were reported in 28% of our studied group. Gram-negative septicemia was the most common cause of toxic death. The 5-year EFS and OS of the whole cohort were 12% and 13%, respectively. Conclusions: In this cohort, no significant survival differences were observed among the methylation subgroups. The higher treatment-related mortality in our cohort compared to the original protocol’s toxic-related deaths suggested that intensive and lengthy chemotherapy regimens may need modification for our population. The need for a short intensified approach, including a limited induction cycle followed by an intensified high-dose consolidation therapy, may be more appropriate for our patients with low socioeconomic status to avoid a repeated and prolonged course of protracted neutropenia. Full article

Atypical teratoid rhabdoid tumor (ATRT) is a rare, aggressive pediatric central nervous system (CNS) tumor that predominantly affects children under the age of 3. It is defined by the inactivation of the SMARCB1 gene, leading to the loss of INI1, a protein essential for cell lineage determination and cell differentiation. Current standard of care treatment requires aggressive multimodal therapy with maximal safe resection, high-dose chemotherapy with autologous stem cell rescue, and radiation, yet overall survival remains < 50%. These intensive regimens have improved overall survival but are associated with significant morbidity and long-term effects. Molecular profiling has significantly advanced the understanding of ATRTs, revealing four molecular subgroups, ATRT-TYR, ATRT-MYC, ATRT-SHH, and ATRT-SMARCA4, each with distinct clinical presentations, oncogenic pathways, and prognoses. Molecular characterization enables better prognostic stratification, guiding treatment decisions and allowing for more personalized therapeutic approaches. Targeted therapies based on these molecular insights remain experimental, and continued exploration of molecular mechanisms and how they differ amongst subgroups is pivotal for the development of less toxic, more effective targeted treatments. Full article

Atypical teratoid rhabdoid tumors are rare embryonal tumors of the nervous system mainly seen in very young children with aggressive behavior and dismal prognosis when treated with conventional chemotherapy only. More recent multimodal strategies combining, variably, high dose chemotherapy, radiotherapy and or intrathecal chemotherapy have led to some stride in survival. We present the results of the most recent clinical trials and registry data for patients treated with these multimodal approaches with survival ranging from 37.1% to 88.9%. We review the current consensus of the molecular characterization of these tumors into 3 subgroups (ATRT-TYR, ATRT-SHH and ATRT-MYC) and discuss the potential clinical impact of molecular subgrouping on survival. We explore other therapeutic tools including intrathecal chemotherapy and maintenance and possible new targeted agents for patients failing multimodal strategies Full article

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. Full article