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Test Paper 2
Published in Teck Yew Chin, Susan Cheng Shelmerdine, Akash Ganguly, Chinedum Anosike, Get Through, 2017
Teck Yew Chin, Susan Cheng Shelmerdine, Akash Ganguly, Chinedum Anosike
Classic medulloblastoma typically arises from the roof of the fourth ventricle and is midline in location in 75%–90% of cases. They are hyperdense on CT; show contrast enhancement in >90% and show restricted diffusion. Atypical teratoid-rhabdoid tumour mimics medulloblastomas radiologically and histologically and have been often misdiagnosed in the past.
CNS Primitive Neuroectodermal Tumors and Other Embryonal Tumors
Published in Dongyou Liu, Tumors and Cancers, 2017
Tumors of embryonal origin comprise a diverse group of malignant lesions (all WHO Grade IV) that were previously distinguished into (i) medulloblastoma (also known as infratentorial primitive neuroectodermal tumor [infratentorial PNET]), (ii) central nervous system (CNS) PNET (formerly supratentorial PNET, consisting of CNS neuroblastoma, CNS ganglioneuroblastoma, medulloepithelioma [MEPL], and ependymoblastoma [EBL]), and (iii) atypical teratoid/rhabdoid tumor (AT/RT).
Rhabdoid Tumor Predisposition Syndrome
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Atypical teratoid/rhabdoid tumor has also been studied, usually in national studies. In a study of the Pediatric Oncology Group [21], 55 patients were identified as eligible participants. Of these, 34 patients were boys and 21 were girls, again indicative of a slight female predilection. The ages of the patients ranged from 2 to 60 months with an average age of presentation of 17 months [21]. Thirty-six of the study patients had tumor located in the posterior fossa. Thirteen patients with tumors in the posterior fossa demonstrated extension into the supratentorial space. Seventeen cases were primary supratentorial tumors (4 suprasellar, 3 involving the pineal gland, 3 parietal lobe, 3 temporal lobe, 2 frontal lobe, and 2 CNS site unspecified). Two cases were multifocal at the time of presentation. Cerebrospinal fluid analysis was performed in 29 patients as part of their presentation; 9 demonstrated positivity for malignant cells [21]. Twenty-five patients went on to develop craniospinal metastases [21]. The metastases are most commonly unresectable. There is now some indication that the atypical teratoid/rhabdoid tumors should be classified into subgroups that may affect treatment. Atypical teratoid/rhabdoid tumor TYR, which is characterized by location in the posterior fossa, very young age at diagnosis, typically less than 1 year, demonstrates overexpression of the genes TYR and MITF [20]. The subgroup atypical teratoid/rhabdoid tumor MYC consists of predominately supratentorial tumors, and the patients are older than average at diagnosis (4−5 years old). The genes MYC, HOX, and HOTAIR are overexpressed [20]. The third subgroup, atypical teratoid rhabdoid tumor SHH, occurs in children between 2 and 5 years old, is either supratentorial or infratentorial, and is characterized by overexpression of the sonic hedgehog genes [20].
Precision medicine for pediatric central nervous system tumors
Published in Expert Review of Precision Medicine and Drug Development, 2019
Daniel C. Moreira, Amar Gajjar
New biologic platforms facilitating high-throughput analyses of pediatric CNS tumors have identified dysregulated proteins that promote tumorigenesis and novel compounds to target these proteins. In cancers where oncogenesis is not heavily dependent on a single pathway, this strategy leverages nononcogenic mutations and cellular adaptations in cancer cells to identify new therapeutic approaches. In a high-throughput, cell-based assay in medulloblastoma, gemcitabine and pemetrexed synergistically inhibited Myc-driven medulloblastoma proliferation [8]. These drugs are now being used in first-line treatment for medulloblastoma (SJMB12). Additional candidate agents for medulloblastoma, such as inhibitors of cell cycle kinases, PARP, and tyrosine kinases, have been identified [9,10]. Atypical teratoid rhabdoid tumor (AT/RT) is a rare embryonal tumor defined by inactivation of the INI-1 locus, with poor prognosis despite multiagent cytotoxic chemotherapy. Insights into the molecular mechanisms driving AT/RT tumorigenesis have also identified candidate agents. Alisertib, an aurora kinase inhibitor, is currently undergoing investigation in a phase 2 trial for AT/RT (NCT02114229).
Atypical Teratoid Rhabdoid Tumor in a Newborn: Can IVF Be a Risk Factor?
Published in Fetal and Pediatric Pathology, 2022
Turkay Rzayev, Kubra Gokce, Safak Gucyetmez, Suheyla Bozkurt, Adnan Dagcinar, Gulnur Tokuc, Akan Yaman, Hulya Bilgen, Eren Ozek
The patient was operated on the 23rd postnatal day. During the surgery, the mass invaded the hemisphere and was subtotally resected. The biopsy revealed a tumor composed of small cells with round-oval eccentric nuclei, prominent nucleoli, and eosinophilic cytoplasmic globules resembling rhabdoid cells. Immunohistochemical analysis demonstrated immunoreactivity with epithelial membrane antigen (EMA), smooth muscle antigen (SMA), synaptophysin, glial fibrillary acidic protein (GFAP) in tumor cells, and the Ki-67 index was 67%. INI-1 (SMARCB1 gene) expression was lost in tumor cells while endothelial cells were positive. Pathologic diagnosis was reported as Atypical Teratoid Rhabdoid Tumor, WHO grade 4 (Figure 1(C–E)).
Pediatric embryonal brain tumors in the molecular era
Published in Expert Review of Molecular Diagnostics, 2020
Bryan K. Li, Salma Al-Karmi, Annie Huang, Eric Bouffet
Pediatric brain tumors are the leading cause of cancer-related death and disability in children. Primary brain tumors, which are the most common solid tumors of childhood, comprise a spectrum of diseases [1]. Of these, 15–20% are embryonal brain tumors (EBTs), a group of highly aggressive cancers that mostly affect young children [2–4]. Though classically exhibiting the small round blue cell morphology of extra-CNS embryonal tumors, they can show varying degrees of differentiation. Historically, the classification of EBTs was based on primary location and histology. For example, medulloblastoma (MB) is an EBT that arose in the infratentorial compartment [5]. Atypical teratoid/rhabdoid tumors (ATRT) presented anywhere in the CNS but classically had distinctive histologic features resembling extra-CNS malignant rhabdoid tumors. Other EBTs presenting above the tentorium were called supratentorial primitive neuroectodermal tumors (sPNET), except for pineoblastoma (PB) which arose from the pineal gland [6]. However, the identification of specific molecular markers expanded the recognition of distinct entities with overlapping locations and histology among other EBTs: loss of function alterations of SMARCB1/INI1 or SMARCA4/BRG1 became a specific marker for ATRTs, while amplification of an embryonic stem cell-enriched miRNA cluster at chr 19q13.42 (C19MC) characterized a highly aggressive C19MC-altered tumor/embryonal tumor multiple rosettes (ETMR) [7–10]. Since then, genomic, transcriptomic, and proteomic (i.e. multi-omic) profiling on large collections of EBTs have revealed additional heterogeneity, with newly proposed subgroups characterized by distinct molecular drivers. While the separation of MB into four subgroups (WNT, SHH, group 3, group 4) has generated a schema for molecular risk stratification and informed preclinical studies of targeted therapies, the rarity of other EBTs provides additional challenges [6,11]. The following review will provide an overview of each type of EBT, describing its clinicopathologic characteristics, specific molecular markers and their significance, and general treatment strategies.