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BACKGROUND. DICER1 is the only miRNA biogenesis component associated with an inherited tumor syndrome, featuring multinodular goiter (MNG) and rare pediatric-onset lesions. Other susceptibility genes for familial forms of MNG likely exist. METHODS. Whole-exome sequencing of a kindred with early-onset MNG and schwannomatosis was followed by investigation of germline pathogenic variants that fully segregated with the disease. Genome- wide analyses were performed on 13 tissue samples from familial and nonfamilial DGCR8-E518K-positive tumors, including MNG, schwannomas, papillary thyroid cancers (PTCs), and Wilms tumors. miRNA profiles of 4 tissue types were compared, and sequencing of miRNA, pre-miRNA, and mRNA was performed in a subset of 9 schwannomas, 4 of which harbor DGCR8- E518K. RESULTS. We identified c.1552G>A;p.E518K in DGCR8, a microprocessor component located in 22q, in the kindred. The variant identified is a somatic hotspot in Wilms tumors and has been identified in 2 PTCs. Copy number loss of chromosome 22q, leading to loss of heterozygosity at the DGCR8 locus, was found in all 13 samples harboring c.1552G>A;p. E518K. miRNA profiling of PTCs, MNG, schwannomas, and Wilms tumors revealed a common profile among E518K hemizygous tumors. In vitro cleavage demonstrated improper processing of pre- miRNA by DGCR8-E518K. MicroRNA and RNA profiling show that this variant disrupts precursor microRNA production, impacting populations of canonical microRNAs and mirtrons. CONCLUSION. We identified DGCR8 as the cause of an unreported autosomal dominant mendelian tumor susceptibility syndrome: familial multinodular goiter with schwannomatosis. FUNDING. Canadian Institutes of Health Research, Compute Canada, Alex's Lemonade Stand Foundation, the Mia Neri Foundation for Childhood Cancer, Cassa di Sovvenzioni e Risparmio fra il Personale della Banca d'Italia, and the KinderKrebslnitiative Buchholz/Holm-Seppensen., Introduction Familial multinodular goiter can occur alone or in combination with other disorders (1). An exemplar of the latter is DICER1 syndrome, attributable to germline pathogenic variants in DICER1, encoding [...]

* Context.--Standards for pathology reporting of cancer are foundational to national and international benchmarking, epidemiology, and clinical trials, with international standards for pathology reporting of cancer being undertaken through the International Collaboration on Cancer Reporting (ICCR). Objective.--To develop standardized templates for brain tumor diagnostic pathology reporting. Design.--As a response to the 2016 updated 4th edition of the WHO (World Health Organization) Classification of Tumours of the Central Nervous System (2016 CNS WHO), an expert ICCR committee developed data sets to facilitate reporting of brain tumors that are classified histologically and molecularly by the 2016 CNS WHO; as such, this represents the first combined histologic and molecular ICCR data set, and required a novel approach with 3 highly related data sets that should be used in an integrated manner. Results.--The current article and accompanying ICCR Web site describe reporting data sets for central nervous system tumors in the hope that they provide easy-to-use and highly reproducible means to issue diagnostic reports in consort with the 2016 CNS WHO. Conclusions.--The consistent use of these templates will undoubtedly prove useful for patient care, clinical trials, epidemiologic studies, and monitoring of neuro-oncologic care around the world. (Arch Pathol Lab Med. 2020;144:196-206; doi: 10.5858/arpa.2018-0565-OA), The value of a structured or synoptic approach to cancer reporting, leading to improvement in the quality and completeness of pathology cancer reports, has been recognized through many studies (1-4) [...]

Atypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant tumor that may not only contain rhabdoid tumor cells but also poorly differentiated small‐round‐blue cells as well as areas with mesenchymal or epithelial differentiation. Little is known on factors associated with histopathological diversity. Recent studies demonstrated three molecular subgroups of AT/RT, namely ATRT‐TYR, ATRT‐SHH, and ATRT‐MYC. We thus aimed to investigate if morphological patterns might be related to molecular subgroup status. Hematoxylin‐eosin stained sections of 114 AT/RT with known molecular subgroup status were digitalized and independently categorized by nine blinded observers into four morphological categories, that is, "rhabdoid," "small‐round‐blue," "epithelial," and "mesenchymal." The series comprised 48 ATRT‐SHH, 40 ATRT‐TYR, and 26 ATRT‐MYC tumors. Inter‐observer agreement was moderate but significant (Fleiss' kappa = 0.47; 95% C.I. 0.41‐0.53; p < 0.001) and there was a highly significant overall association between morphological categories and molecular subgroups for each of the nine observers (p < 0.0001). Specifically, the category "epithelial" was found to be over‐represented in ATRT‐TYR (p < 0.000001) and the category "small‐round‐blue" to be over‐represented in ATRT‐SHH (p < 0.01). The majority of ATRT‐MYC was categorized as "mesenchymal" or "rhabdoid," but this association was less compelling. The specificity of the category "epithelial" for ATRT‐TYR was highest and accounted for 97% (range: 88‐99%) whereas sensitivity was low [49% (range: 35%–63%)]. In line with these findings, cytokeratin‐positivity was highly overrepresented in ATRT‐TYR. In conclusion, morphological features of AT/RT might reflect molecular alterations and may also provide a first hint on molecular subgroup status, which will need to be confirmed by DNA methylation profiling. [ABSTRACT FROM AUTHOR]

Loss of nuclear SMARCB1 (INI1/hSNF5/BAF47) protein expression due to biallelic mutations of the SMARCB1 tumor suppressor gene is a hallmark of atypical teratoid/rhabdoid tumors (ATRT), but the presence of cytoplasmic SMARCB1 protein in these tumors has not yet been described. In a series of 102 primary ATRT, distinct cytoplasmic SMARCB1 staining on immunohistochemistry was encountered in 19 cases (19%) and was highly over-represented in cases showing pathogenic sequence variants leading to truncation or mutation of the C-terminal part of SMARCB1 (15/19 vs. 4/83; Chi-square: 56.04, p = 1.0E−10) and, related to this, in tumors of the molecular subgroup ATRT-TYR (16/36 vs. 3/66; Chi-square: 24.47, p = 7.6E−7). Previous reports have indicated that while SMARCB1 lacks a bona fide nuclear localization signal, it harbors a masked nuclear export signal (NES) and that truncation of the C-terminal region results in unmasking of this NES leading to cytoplasmic localization. To determine if cytoplasmic localization found in ATRT is due to unmasking of NES, we generated GFP fusions of one of the SMARCB1 truncating mutations (p.Q318X) found in the tumors along with a p.L266A mutation, which was shown to disrupt the interaction of SMARCB1-NES with exportin-1. We found that while the GFP-SMARCB1(Q318X) mutant localized to the cytoplasm, the double mutant GFP-SMARCB1(Q318X;L266A) localized to the nucleus, confirming NES requirement for cytoplasmic localization. Furthermore, cytoplasmic SMARCB1(Q318X) was unable to cause senescence as determined by morphological observations and by senescence-associated β-galactosidase assay, while nuclear SMARCB1(Q318X;L266A) mutant regained this function. Selinexor, a selective exportin-1 inhibitor, was effective in inhibiting the nuclear export of SMARCB1(Q318X) and caused rapid cell death in rhabdoid tumor cells. In conclusion, inhibition of nuclear export restores nuclear localization and residual tumor suppressor function of truncated SMARCB1. Therapies aimed at preventing nuclear export of mutant SMARCB1 protein may represent a promising targeted therapy in ATRT harboring truncating C-terminal SMARCB1 mutations. [ABSTRACT FROM AUTHOR]

Keywords: blastematous; choroid plexus tumour; DNA methylation profiling; mesenchymal EN blastematous choroid plexus tumour DNA methylation profiling mesenchymal 1 3 3 02/03/22 20220215 NES 220215 INTRODUCTION Choroid plexus tumours are intraventricular neoplasms derived from the choroid plexus epithelium. (F) Black scale bars represent 500 m for panel (B) and 50 m for panels (C)-(E) gl DNA-methylation profiling (Illumina Methylation EPIC BeadChip) using the Heidelberg central nervous system (CNS) tumour classifier3 showed the case to be a "choroid plexus tumour, subclass paediatric B" (calibrated score 0.99), and the similarity with this molecular subgroup was further confirmed by t-SNE analysis (Figure 1F). The high similarity of the DNA methylation profile with choroid plexus tumours of the molecular subclass paediatric B is characteristic for malignant choroid plexus tumours and may suggest that the tumour secondarily acquired blastematous features. [Extracted from the article]

The author discusses the publication of the "2016 World Health Organization Classification of Tumors of the Central Nervous System" (2016 CNS WHO) which represents the advancement of the classification of human brain tumors and facilitates a precise diagnosis of well-understood entities.

Astrocytoma and oligodendroglioma are histologically and genetically well-defined entities. The majority of astrocytomas harbor concurrent TP53 and ATRX mutations, while most oligodendrogliomas carry the 1p/19q co-deletion. Both entities share high frequencies of IDH mutations. In contrast, oligoastrocytomas (OA) appear less clearly defined and, therefore, there is an ongoing debate whether these tumors indeed constitute an entity or whether they represent a mixed bag containing both astrocytomas and oligodendrogliomas. We investigated 43 OA diagnosed in different institutions employing histology, immunohistochemistry and in situ hybridization addressing surrogates for the molecular genetic markers IDH1R132H, TP53, ATRX and 1p/19q loss. In all but one OA the combination of nuclear p53 accumulation and ATRX loss was mutually exclusive with 1p/19q co-deletion. In 31/43 OA, only alterations typical for oligodendroglioma were observed, while in 11/43 OA, only indicators for mutations typical for astrocytomas were detected. A single case exhibited a distinct pattern, nuclear expression of p53, ATRX loss, IDH1 mutation and partial 1p/19q loss. However, this was the only patient undergoing radiotherapy prior to surgery, possibly contributing to the acquisition of this uncommon combination. In OA with oligodendroglioma typical alterations, the portions corresponding to astrocytic part were determined as reactive, while in OA with astrocytoma typical alterations the portions corresponding to oligodendroglial differentiation were neoplastic. These data provide strong evidence against the existence of an independent OA entity. [ABSTRACT FROM AUTHOR]

Background: The clinical impact of routine neuropathologic examination of samples from patients with intracerebral hemorrhage (ICH) is unclear. Methods: Therefore, we evaluated a consecutive series of 378 surgical specimens from patients with ICH concerning demographic data, localization of hemorrhage, preoperative clinical diagnosis and neuropathological diagnosis. Results: Histological examination revealed the putative origin of ICH in 143 cases (37.8%). Vascular pathologies were detected in 127 patients (33.6%), while tumors were identified in 9 patients (2.4%), infarction in 6 patients (1.6%) and abscess in 1 patient (0.3%). Preoperatively, tumor was considered in 65 patients (17.2%), while vascular malformations were supposed in 94 patients (24.9%), infarction in 18 cases (4.8%) and abscess in 3 cases (0.8%). In 198 patients (52.4%) no specific assumption was made. Conclusions: Comparing preoperative assumptions and histological diagnoses, tumor, vascular malformations and infarctions were clinically overestimated, while arteriolosclerosis and amyloid angiopathy were underestimated. In conclusion, we found that histological findings potentially affecting clinical management and prognosis were obtained in 37.8% of cases. Our data suggest that histopathological examination of intracerebral hemorrhage provides important information for patient management and should be routinely performed. [ABSTRACT FROM AUTHOR]

We report herein a choroid plexus papilloma in a beluga whale (Delphinapterus leucas). This case was positive for choroid plexus tumor marker Kir7.1 on immunohistochemistry. These results and the high conservation of Kir7.1 across species at the amino acid sequence level strongly suggest that antibodies directed against Kir7.1 not only can be employed for the diagnosis of choroid plexus tumors in cetaceans, but are also likely to be diagnostically useful in other animal species. [ABSTRACT FROM AUTHOR]

We report on three adult patients with primary glioblastomas showing prominent adipocytic (lipomatous) differentiation, hence referred to as “glioblastomas with adipocyte-like tumor cell differentiation.” Histologically, the tumors demonstrated typical features of glioblastoma but additionally contained areas consisting of glial fibrillary acidic protein (GFAP)-positive astrocytic tumor cells resembling adipocytes, that is, containing large intracellular lipid vacuoles. Comparative genomic hybridization (CGH) and focused molecular genetic analyses demonstrated gains of chromosomes 7, losses of chromosomes 9 and 10, as well as homozygous deletion of p14ARF in one of the tumors. The second tumor showed gains of chromosomes 3, 4, 8q and 12 as well as losses of chromosomes 10, 13, 15q, 19 and 22. In addition, this tumor carried homozygous deletions of CDKN2A and p14ARF as well as point mutations in the TP53 and PTEN genes. The third tumor also had a mutation in the PTEN gene. None of the tumors demonstrated EGFR, CDK4 or MDM2 amplification. Taken together, our results define a rare glioblastoma differentiation pattern and indicate that glioblastomas with adipocyte-like tumor cell differentiation share common molecular genetic features with other primary glioblastomas. [ABSTRACT FROM AUTHOR]

Pattern and extent of epithelial membrane antigen (EMA) immunoreactivity in ependymomas as compared to other glial tumors have only been investigated in small series. To determine sensitivity and specificity of EMA staining, 54 ependymomas were evaluated in comparison to 54 glioblastomas, 43 fibrillary astrocytomas and 21 oligodendrogliomas. Distinct punctate intracytoplasmic EMA immunoreactivity was observed in 48/54 ependymomas (89%), whereas ring-like EMA staining was observed in 17/54 ependymomas (31%). Apart from the absence in most myxopapillary ependymomas, neither staining pattern was related to tumor grade or localization. Dot-like EMA immunoreactivity was less frequently observed in glioblastomas [32/54 (59%), P<0.05 vs ependymomas], fibrillary astrocytomas [10/43 (23%), P<0.001 vs ependymomas] and oligodendrogliomas [2/21 (10%), P<0.001 vs ependymomas], whereas ring-like EMA staining was absent. Sensitivity and specificity of punctate EMA staining for the diagnosis of ependymoma as compared to other glial tumors were determined: A finding of 5 EMA dots/high-power field was associated with a sensitivity of 72% and a specificity of 81%. The presence of ring-like EMA positive structures was less sensitive (32%), but highly specific (100%). To conclude, distinct punctate and ring-like EMA staining might serve as sensitive and specific markers of ependymal differentiation in glial tumors and, thus, may aid the diagnosis of ependymoma. [ABSTRACT FROM AUTHOR]

Seven granular cell tumours (GCT) were studied by comparative genomic hybridisation. These consisted of two cerebral and one pituitary GCT as well as four other central nervous system tumours predominantly composed of granular cells (one glioblastoma, meningioma, ganglioglioma and neurinoma each). DNA copy number changes were found in four of seven tumours. Overall, losses (mean: 1.0 per tumour) were more frequent than gains (mean: 0.6 per tumour) and no high-level gains were found. The only DNA copy number change found in two tumours (both cerebral GCT) was loss of 13q21, while the other nine aberrations were only encountered once each: the granular cells of one cerebral GCT additionally showed +1p32-pter, +9q33-qter, +20q, –4, and –18q, of the glioblastoma +7 and –10, and of the meningioma –1p and –22q, while the pituitary GCT, the ganglioglioma and the neurinoma showed no imbalances. Our data suggest that a variety of genetic changes are associated with granular cell formation and support the notion that GCT are not a distinct tumour entity characterised by specific chromosomal imbalances but rather a degenerative phenomenon of cells of various origin showing DNA copy number changes akin to the underlying tumour. [ABSTRACT FROM AUTHOR]

Four pituitary carcinoma metastases [two adrenocorticotropic hormone (ACTH) and prolactin cell tumors each] were studied by comparative genomic hybridization. Chromosomal gains were found in all four carcinoma metastases, but losses only in the two prolactin cell carcinoma metastases. Overall, pituitary carcinoma metastases showed an average of 8.3 chromosomal imbalances per tumor (7 gains vs 1.3 losses), 10 in prolactin cell carcinoma metastases (7.5 gains vs 2.5 losses) and 6.5 in ACTH cell carcinoma metastases (6.5 gains vs 0 loss). The most common changes were gains of chromosome 5, 7p, and 14q (in three tumors each). High-level gains were found on 13q22-qter and 14q (two cases each) and on 1q, 3p, 7, 8, 9p, and 21q (one case each). To date, gains of chromosome 14q have not been reported among pituitary tumors. It remains to be shown whether gain of 14q is associated with malignant progression and metastatic dissemination of pituitary carcinomas. [ABSTRACT FROM AUTHOR]

The article discusses the study that investigates the increased mitotic activity's prognostic value of choroid plexus papillomas (CPP) and atypical choroid plexus papillomas (aCCP) in children. It states that the patients' formalin-fixed paraffin-embedded tumor samples were neuropathologically reviewed. Findings support the association between the increased mitotic activity and the high probability of the recurrence of CPP in children.

Eight subependymal giant cell astrocytomas (SEGA) were studied by comparative genomic hybridisation. These consisted of six primary SEGA and two recurrences gained from six paediatric patients suffering from tuberous sclerosis complex (TSC). No DNA copy number changes were found in any of the tumours. Our data show that chromosomal imbalances are absent or very rare events in primary and recurrent SEGA and that no aberrations were detected at the sites of the TSC-associated genes, thus indicating that mutational inactivation of one of the TSC genes is not followed by genomic instability. [ABSTRACT FROM AUTHOR]

Hereditary paraganglioma of the head and neck is associated with germline mutations in the SDHD gene, which encodes a mitochondrial respiratory chain protein. Paragangliomas of the central nervous system are very rare, occur almost exclusively in the cauda equina of the spinal cord and are considered non-familial. In the present study, we screened 22 apparently sporadic paragangliomas of the cauda equina for SDHD mutations. One spinal paraganglioma and similar cerebellar tumours that developed 22 years later in the same patient contained a missense mutation at codon 12 (GGT→AGT, Gly→Ser) and a silent mutation at codon 68 (AGC→AGT, Ser→Ser). There was no family history of paragangliomas but DNA from white blood cells of this patient showed the same sequence alterations, indicating the presence of a germline mutation. All other cases of spinal paraganglioma had the wild-type SDHD sequence, except one case with a silent mutation at codon 68 (AGC→AGT, Ser→Ser). This is the first observation indicating that inherited SDHD mutations may occasionally cause the development of paragangliomas in the central nervous system. Oncogene (2001) 20, 5084–5086. [ABSTRACT FROM AUTHOR]