Corrigendum: Pediatric CNS tumors and 2021 WHO classification: what do oncologists need from pathologists?

[This corrects the article DOI: 10.3389/fnmol.2024.1268038.].

Pediatric CNS tumors and 2021 WHO classification: what do oncologists need from pathologists?

The fifth edition of the WHO Classification of Tumors of the Central Nervous System (CNS), published in 2021, established new approaches to both CNS tumor nomenclature and grading, emphasizing the importance of integrated diagnoses and layered reports. This edition increased the role of molecular diagnostics in CNS tumor classification while still relying on other established approaches such as histology and immunohistochemistry. Moreover, it introduced new tumor types and subtypes based on novel diagnostic technologies such as DNA methylome profiling. Over the past decade, molecular techniques identified numerous key genetic alterations in CSN tumors, with important implications regarding the understanding of pathogenesis but also for prognosis and the development and application of effective molecularly targeted therapies. This review summarizes the major changes in the 2021 fifth edition classification of pediatric CNS tumors, highlighting for each entity the molecular alterations and other information that are relevant for diagnostic, prognostic, or therapeutic purposes and that patients' and oncologists' need from a pathology report.

Histologic Analysis of Idiopathic Pulmonary Fibrosis by Morphometric and Fractal Analysis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic lung disorder, ultimately leading to respiratory failure and death. Despite great research advances in understanding the mechanisms underlying the disease, its diagnosis, and its treatment, IPF still remains idiopathic without known biological or histological markers able to predict disease progression or response to treatment. The histologic hallmark of IPF is usual interstitial pneumonia (UIP), with its intricate architectural distortion and temporal inhomogeneity. We hypothesize that normal lung alveolar architecture can be compared to fractals, such as the Pythagoras tree with its fractal dimension (Df), and every pathological insult, distorting the normal lung structure, could result in Df variations. In this study, we aimed to assess the UIP histologic fractal dimension in relationship to other morphometric parameters in newly diagnosed IPF patients and its possible role in the prognostic stratification of the disease. Clinical data and lung tissue specimens were obtained from twelve patients with IPF, twelve patients with non-specific interstitial pneumonia (NSIP), and age-matched "healthy" control lung tissue from patients undergoing lung surgery for other causes. Histology and histomorphometry were performed to evaluate Df and lacunarity measures, using the box counting method on the FracLac ImageJ plugin. The results showed that Df was significantly higher in IPF patients compared to controls and fibrotic NSIP patients, indicating greater architectural distortion in IPF. Additionally, high Df values were associated with higher fibroblastic foci density and worse prognostic outcomes in IPF, suggesting that Df may serve as a potential novel prognostic marker for IPF. The scalability of Df measurements was demonstrated through repeated measurements on smaller portions from the same surgical biopsies, which were selected to mimic a cryobiopsy. Our study provides further evidence to support the use of fractal morphometry as a tool for quantifying and determining lung tissue remodeling in IPF, and we demonstrated a significant correlation between histological and radiological Df in UIP pattern, as well as a significant association between Df and FF density. Furthermore, our study demonstrates the scalability and self-similarity of Df measurements across different biopsy types, including surgical and smaller specimens.

Case report of a pediatric medulloblastoma with concurrent MYC and MYCN subclonal amplification in distinct populations of neoplastic cells.

Medulloblastomas (MDBs) are classified into molecular groups showing peculiar immunohistochemical and genetic features and distinct DNA methylation profile. Group 3 and group 4 MDBs have the worst prognosis; the former is treated with high-risk protocols and features MYC amplification, whereas the latter receives standard-risk protocols and harbors MYCN amplification. Herein, we report a unique case of MDB showing histological and immunohistochemical features consistent with non-SHH/non-WNT classic MDB, with both MYCN (30% of tumor cells) and MYC (5-10% tumor cells) amplification in distinct subclones of neoplastic cells at fluorescence in situ hybridization (FISH), characterized by specific patterns. In spite of MYC amplification in only a small percentage of tumor cells, this case had DNA methylation profile consistent with group 3, emphasizing the importance to test both MYC and MYCN amplifications at a single cell level using highly sensitive methods, such as FISH, for diagnostic and therapeutic purposes.

Detection of human neurotropic JCPyV DNA sequence in pediatric anaplastic xanthoastrocytoma.

Due to its peculiar histopathological findings, pleomorphic xanthoastrocytoma (PXA), a rare cerebral tumor of young adults with a slow growth and a good prognosis, resembles to the lytic phase of progressive multifocal leukoencephalopathy, a fatal neurodegenerative disease caused by JC polyomavirus (JCPyV). Therefore, the presence of JCPyV DNA was examined in an 11-year-old child with xanthoastrocytoma, WHO grade 3, by quantitative PCR (qPCR) and nested PCR (nPCR) using primers amplifying sequences encoding the N- and C-terminal region of large T antigen (LTAg), the non-coding control region (NCCR), and viral protein 1 (VP1) DNA. The expression of transcripts from LTAg and VP1 genes was also evaluated. In addition, viral microRNAs' (miRNAs) expression was investigated. Cellular p53 was also searched at both DNA and RNA level. qPCR revealed the presence of JCPyV DNA with a mean value of 6.0 × 104 gEq/mL. nPCR gave a positive result for the 5' region of the LTAg gene and the NCCR, whereas 3' end LTAg and VP1 DNA sequences were not amplifiable. Only LTAg transcripts of 5' end were found whereas VP1 gene transcript was undetectable. Although in most cases, either Mad-1 or Mad-4 NCCRs have been identified in association with JCPyV-positive human brain neoplasms, the archetype NCCR structure was observed in the patient's sample. Neither viral miRNA miR-J1-5p nor p53 DNA and RNA were detected. Although the expression of LTAg supports the possible role of JCPyV in PXA, further studies are warranted to better understand whether the genesis of xanthoastrocytoma could depend on the transformation capacity of LTAg by Rb sequestration.

Pre-analytics, a national survey of Senonetwork Italia breast centers: Much still to do ahead.

INTRODUCTION: Pre-analytics involves handling and processing of microbiopsy and surgical specimen. It is critical for the preservation of morphology and the integrity of molecular markers, which are paramount as prognostic and predictive factors in breast cancer. Although pre-analytical variables in breast cancer are codified by national and international guidelines, there is currently no data on their actual endorsement in clinical practice among Breast Units (BU). MATERIALS AND METHODS: An anonymous questionnaire was sent by e-mail by Senonetwork Italia, a no-profit organization representing the multidisciplinary network of BU in Italy. The questionnaire involved twenty-four questions concerning critical issues related to the average time and transport temperature of the samples, monitoring of warm and cold ischemia, average fixation time for biopsies and surgical specimens, inking of the margins, and radiography of the operating sample. RESULTS: Forty-nine of 113 affiliated BU (43%), involved in the management of 44% of all breast cancer treated every year in Italy, answered the questionnaire. More than 90% of the BU reported a biopsy/VABB fixation time between 6 and 24 h. Only 41% of the Centers received the fresh operative sample to be sectioned immediately, 20% used the vacuum method and the sample arrived in the laboratory within 24-72 h. Delay in sectioning the sample was reported in as many as 40% of BU, while hot and cold ischemia time was monitored in only 4.2% and 6.2% of BU, respectively. CONCLUSION: Critical issues on pre-analytics are reported by the majority of dedicated BU in Italy. This represents a major challenge regarding quality of care, and improvements are needed in order to obtain valid and reproducible results of prognostic and predictive factors.

Recurrent prenatal PIEZO1-related lymphatic dysplasia: Expanding molecular and ultrasound findings.

Generalized lymphatic dysplasia (GLD), characterized by lymphedema, lymphangiectasias, chylothorax, effusions, represents a recognized cause of fetal hydrops. We describe for the first time recurrent pregnancies showing different ultrasound presentations of lymphatic dysplasia. The first fetus displayed diffuse subcutaneous cysts and septations while the second one presented fetal hydrops. Exome sequencing results at 18 gestational weeks in the second pregnancy showed compound heterozygosity for two novel PIEZO1 variants, afterwards detected also in the first fetus and in the heterozygous parents. Both ultrasound and genetic findings expand the current knowledge of PIEZO1-related GLD. We suggest exome sequencing in hydropic fetuses with normal cytogenetics and in pregnancies with recurrent hydrops/lymphatic dysplasia.