World Health Organization Classification Research Articles

Seromucinous tumors of ovary: A case series

Seromucinous neoplasms are new category of ovarian epithelial tumor in the 2014 revised World Health Organization classification. Surface epithelial neoplasms are the most common ovarian tumors. Based on the degree of stratification and the presence or absence of invasion, these epithelial proliferations are further divided into benign, borderline, and malignant categories. Benign tumors are divided into three subtypes: cystadenoma (cystic areas), cystadenofibroma (cystic and fibrous areas), and adenofibroma (predominantly fibrous sections). Serous adenofibromas are rare variant of serous surface epithelial tumors. They affect females between the ages of 15 and 65 and make up 1.7% of all benign ovarian tumors. Serous tumor with a solid, fibrous component is designated as serous cystadenofibroma in which both serous and mucinous components are closely intermixed. Seromucinous adenofibroma is a benign cystic neoplasm composed of glands and cysts lined by an admixture of bland mullerian type epithelium which includes ciliated, endocervical type mucinous, and endometroid. They have a characteristic prominent fibromatous hypocellular stroma which helps differentiate it from the commoner cystadenoma. Seromucinous borderline tumors is 10% -20% of all epithelial ovarian tumors. Develops in younger age, usually bilateral in upto 40%, associated with endometriosis. We discuss about four different cases of seromucinous tumor reported in our institute.

Microsecretory adenocarcinoma of the hard palate: a case report and literature review

Microsecretory adenocarcinoma (MSA) is a new type of salivary gland neoplasm identified in the 2022 World Health Organization Classification of Head and Neck Tumour (Skalova et al., Head Neck Pathol 16:40-53, 2022) and is characterized by a unique set of histomorphologic and immunohistochemical features and a recurrent MEF2C::SS18 fusion. MSA was initially misdiagnosed as another salivary gland tumour due to its similar morphology; until recently, only fewer than 50 cases were reported. We present a case of MSA of the hard palate with diverse architectural growth patterns, bland cytological features, abundant basophilic intraluminal secretions and fibromyxoid stroma. The tumour cells were positive for the SOX10, S100, and p63 protein and negative for the p40 protein according to immunohistochemistry. SS18 gene rearrangement was demonstrated via break-apart fluorescence in situ hybridization. We also provided a comprehensive literature review and integrated the clinicopathological features, immunophenotype, and molecular alterations of the disease. A comprehensive understanding of MSA enables us to accurately distinguish and categorize MSA from other salivary gland tumours with analogous morphologies.

Microsecretory adenocarcinoma of the hard palate: a case report and literature review

Microsecretory adenocarcinoma (MSA) is a new type of salivary gland neoplasm identified in the 2022 World Health Organization Classification of Head and Neck Tumour (Skalova et al., Head Neck Pathol 16:40-53, 2022) and is characterized by a unique set of histomorphologic and immunohistochemical features and a recurrent MEF2C::SS18 fusion. MSA was initially misdiagnosed as another salivary gland tumour due to its similar morphology; until recently, only fewer than 50 cases were reported. We present a case of MSA of the hard palate with diverse architectural growth patterns, bland cytological features, abundant basophilic intraluminal secretions and fibromyxoid stroma. The tumour cells were positive for the SOX10, S100, and p63 protein and negative for the p40 protein according to immunohistochemistry. SS18 gene rearrangement was demonstrated via break-apart fluorescence in situ hybridization. We also provided a comprehensive literature review and integrated the clinicopathological features, immunophenotype, and molecular alterations of the disease. A comprehensive understanding of MSA enables us to accurately distinguish and categorize MSA from other salivary gland tumours with analogous morphologies.

Interpretation of lymphoid proliferations and lymphomas associated with immune deficiency and dysregulation in the 5th edition WHO classification of haematolymphoid tumours

The fifth edition of the World Health Organization (WHO) classification of lymphohematopoietic system tumors updated the terminology, types of lesions, diagnostic criteria, nomenclature, and other aspects of lymphoid proliferations and lymphomas associated with immune deficiency and dysregulation. The important updates and main changes in this section were briefly introduced, in order to guide the precise classification of lymphoid proliferations and lymphomas associated with immune deficiency and dysregulation, and standardize pathological reports.

Myelodysplastic/Myeloproliferative Neoplasms with Features Intermediate between Primary Myelofibrosis and Chronic Myelomonocytic Leukemia: Case Series and Review of the Entity

Diagnosis of myeloid neoplasm is currently performed according to the presence of a predetermined set of clinical, morphological, and molecular diagnostic criteria agreed upon by a consensus of experts. Even strictly adhering to these criteria, it is possible to encounter patients who present features that are not easily ascribable to a single disease category. This is the case, e.g., of patients with de novo myeloid neoplasms with features intermediate between primary myelofibrosis (PMF) and chronic myelomonocytic leukemia (CMML). In this study, we retrospectively searched the pathological database of IRCCS Humanitas Research Hospital to identify cases of chronic myeloid neoplasm with monocytosis with a driver mutation of classic myeloproliferative neoplasms (MPN) and showing morphological MPN features. For each case, we assessed all epidemiological, clinical, histopathological, and molecular data. Then, we carried out a literature review, searching for cases with features similar to those of our patients. We retrieved a total of 13 cases presenting such criteria (9 from the literature review and 4 from our institution); in all of them, there was a coexistence of clinical, histopathological, and molecular myelodysplastic and myeloproliferative features. To date, according to current classifications (World Health Organization and International Consensus Classification), given the presence/absence of essential features for PMF or CMML, these patients should be formally diagnosed as myelodysplastic/myeloproliferative neoplasm unclassified/not otherwise specified (U/NOS). This review aims to summarize the features of these difficult cases and discuss their differential diagnosis and their classification according to the novel classifications and the existing literature on overlapping myeloid neoplasms.

Myelodysplastic/Myeloproliferative Neoplasms with Features Intermediate between Primary Myelofibrosis and Chronic Myelomonocytic Leukemia: Case Series and Review of the Entity

Diagnosis of myeloid neoplasm is currently performed according to the presence of a predetermined set of clinical, morphological, and molecular diagnostic criteria agreed upon by a consensus of experts. Even strictly adhering to these criteria, it is possible to encounter patients who present features that are not easily ascribable to a single disease category. This is the case, e.g., of patients with de novo myeloid neoplasms with features intermediate between primary myelofibrosis (PMF) and chronic myelomonocytic leukemia (CMML). In this study, we retrospectively searched the pathological database of IRCCS Humanitas Research Hospital to identify cases of chronic myeloid neoplasm with monocytosis with a driver mutation of classic myeloproliferative neoplasms (MPN) and showing morphological MPN features. For each case, we assessed all epidemiological, clinical, histopathological, and molecular data. Then, we carried out a literature review, searching for cases with features similar to those of our patients. We retrieved a total of 13 cases presenting such criteria (9 from the literature review and 4 from our institution); in all of them, there was a coexistence of clinical, histopathological, and molecular myelodysplastic and myeloproliferative features. To date, according to current classifications (World Health Organization and International Consensus Classification), given the presence/absence of essential features for PMF or CMML, these patients should be formally diagnosed as myelodysplastic/myeloproliferative neoplasm unclassified/not otherwise specified (U/NOS). This review aims to summarize the features of these difficult cases and discuss their differential diagnosis and their classification according to the novel classifications and the existing literature on overlapping myeloid neoplasms.

Linking physiology and demographics, non-ocular pathology and pharmaceutical drug use to standard OCT measures of the inner retina: The PPP project.

To assess the associations between physiology and demographics, non-ocular pathology and pharmaceutical drug use against peri-papillary retinal nerve fibre layer thickness (pRNFL T) and other optical coherence tomography (OCT) inner retinal measures in normal, healthy eyes. A retrospective, cross-sectional study of 705 consecutive participants with bilateral normal, healthy optic nerves and maculae. PRNFL Ts, vertical cup/disc ratio (CDR), cup volume and macular ganglion cell layer-inner plexiform layer (GCL-IPL) Ts were extracted from Cirrus OCT scans, then regressed against predictor variables of participants' physiology and demographics (eye laterality, refraction, intraocular pressure [IOP], age, sex, race/ethnicity, etc.) and non-ocular pathology and pharmaceutical drug use according to the World Health Organisation classifications. Associations were assessed for statistical significance (p < 0.05) and clinical significance (|β| > 95% limits of agreement for repeated measures). A multitude of non-ocular pathology and pharmaceutical drug use were statistically and clinically significantly associated with deviations in standard OCT inner retinal measures, exceeding the magnitude of other factors such as age, IOP and race/ethnicity. Thinner inner retina and larger optic nerve cup measures were linked to use of systemic corticosteroids, sex hormones/modulators, presence of vasomotor/allergic rhinitis and other diseases and drugs (up to -29.3 [-49.88, -8.72] μm pRNFL T, 0.31 [0.07, 0.54] vertical CDR, 0.29 [0.03, 0.54] mm3 cup volume and -10.18 [-16.62, -3.74] μm macular GCL-IPL T; all p < 0.05). Thicker inner retina and smaller optic nerve cup measures were diffusely associated with use of antineoplastic agents, presence of liver or urinary diseases and other diseases and drugs (up to 67.12 [64.92, 69.31] μm pRNFL T, -0.31 [-0.53, -0.09] vertical CDR, -0.06 [-0.11, 0] mm3 cup volume and 28.84 [14.51, 43.17] μm macular GCL-IPL T; all p < 0.05). There are a multitude of systemic diseases and drugs associated with altered OCT inner retinal measures, with magnitudes far exceeding those of other factors such as age, IOP and race/ethnicity. These systemic factors should at least be considered during OCT assessments to ensure precise interpretation of normal versus pathological inner retinal health.

Clinical implications of the 2022 WHO classification on the multidisciplinary management of PitNETS patients.

The review explores the 2022 update to the World Health Organization (WHO) classification of pituitary adenomas, now referred to as pituitary neuroendocrine tumors (PitNETs), and his possible impact on the clinical management of PitNET patients. The review highlights the differences and the evolution from the 2017 to 2022 version, with the current classification considering the lineage of the tumor cells, cell type, hormones produced, and other auxiliary characteristics for a comprehensive histological classification. The revision in terminology reflects a broader perspective on neuroendocrine neoplasia. The new approach based on transcription factors, hormone expression and other biomarkers has allowed a major revision of the nomenclature and a more accurate classification of pituitary adenomas. Furthermore, in some cases this approach is also assuming a prognostic value, useful in clinical practice. However, despite this elaborate classification and stratification, the review points out the lack of a robust grading or staging system and suggests the need for further research and validation of diagnostic methods. Despite these limitations, the revised classification presents a significant step towards understanding and managing PitNETs patients.

Peripartum anesthesia management and outcomes of patients with congenital heart disease: a single-center retrospective analysis (2009–2023)

BackgroundAdvances in medicine have enabled more patients with congenital heart disease (CHD) to become pregnant. However, these patients face significant challenges during the peripartum period. Current peripartum anesthesia guidelines for CHD patients mainly rely on case reports and small series. MethodsIn this retrospective study at a high-volume tertiary care center, we analyzed peripartum anesthetic approaches, postpartum hemorrhage (PPH) incidence, and maternal outcomes in CHD patients stratified by the modified World Health Organization (mWHO) classification. ResultsAmong 85 473 deliveries between 2009 and 2023, 409 occurred in 282 patients with CHD. Cesarean deliveries were significantly more frequent in mWHO class III, p=0.005. Labor epidural analgesia was the most common analgesic modality for vaginal deliveries (epidural rate was 71.1% with no differences between mWHO classes). Anesthesia management for cesarean deliveries varied significantly by class p<0.001. While spinal anesthesia was predominant in classes I and II, combined spinal-epidural anesthesia was more common in class III. PPH incidence was 6.4%, with no significant difference across classes, and no association was found between mWHO class severity and PPH risk (OR 0.97; 95% CI; 0.93 to 1.02, p=0.2). Higher mWHO classes correlated with significantly higher intensive care unit (ICU) admission rates, longer hospital stays, and one-year cardiac hospitalizations. ConclusionIn this retrospective study on the peripartum anesthetic management and outcomes of CHD patients stratified by mWHO class, cases with greater mWHO class were more likely to deliver preterm, by cesarean delivery, with a combined spinal-epidural anesthetic and an arterial line placement for that cesarean delivery. They overall had a longer hospital stay and were more likely to be admitted to the ICU. However, the overall risk of PPH did not increase with mWHO class severity.

Pathological Diagnosis and Genetic Alterations of Meningioma

Meningiomas, renowned for their histological diversity, are one of the most prevalent brain tumors. Some meningiomas show unusual histomorphology, especially in intraoperative rapid diagnosis. Therefore, clinical and radiological information is crucial for pathological diagnosis. Before the 2021 World Health Organization Classification of Tumors of the Central Nervous System(5th edition), pathological diagnosis relied solely on histopathological features. However, this classification introduced new diagnostic criteria for anaplastic meningiomas, which now include TERT promoter mutations and the homozygous deletion of CDKN2A/B, indicating the necessity of genetic analysis. Some rhabdoid and papillary meningiomas have BAP1 alterations, which tend to demonstrate an aggressive clinical course and may represent a phenotype of BAP1-related tumor predisposition syndrome. Heterozygous deletion of CDKN2A/B and loss of H3 p.K28me3(K27me3)are also associated with poor prognosis. Although some immunohistochemical markers like MTAP may serve as surrogates for the homozygous deletion of CKKN2A/B, genetic analysis is required to confirm TERT promoter mutations. Therefore, in routine clinical practice, neurosurgeons and pathologists prioritize appropriate formalin fixation to facilitate genetic analysis using pathological specimens.

Elucidating hematological profile and electrolyte balance in oral cancer patients.

Oral cancer is a serious health issue in both the developing and developed worlds, and it is one of the most common forms of cancer of the head and neck. In accordance with the 2017 World Health Organization classification, oral cancer can affect any part of the mouth, including the buccal mucosa, the front two-thirds of the tongue, the lip, the palate, the vestibule, the alveolus, the floor of the mouth, and the gingivae. Hematology and electrolyte balance have been proposed as tumor indicators and paths into cancer's genesis. Examining the patient's blood count and electrolyte levels in order to better understand their oral cancer. Electrolyte abnormalities are common in cancer patients and may be caused by the disease itself or by treatment. Hyponatremia is the most frequent electrolyte problem in cancer patients, and it is typically caused by the syndrome of improper ADH secretion. Although electrolyte problems are associated with a worse prognosis for cancer patients, timely and effective therapy has the potential to enhance both short- and long-term results and quality of life. Hematological tests on patients with oral cancer, including differential cell count, white blood cell count, and hemoglobin level. Compared to healthy controls, oral cancer patients show statistically significant differences in a number of biochemical parameters, including electrolytes (sodium, P<0.05; potassium, P=0.89; chloride, P<0.05); differential count (neutrophils, P<0.05; basophils, P<0.05). A significant risk factor for cancer patients is an electrolyte imbalance, which has been linked to inappropriate anti-diabetic hormone release. Clinicians will find these shifts in electrolytic level helpful in diagnosing and tracking oral cancer. Potentially malignant oral disorders and Oral squamous cell carcinoma may be better predicted using a combination of TLC, neutrophil, and lymphocyte counts, as shown in this study.

Chronic myelomonocytic leukemia with ring sideroblasts/SF3B1 mutation presents with low monocyte count and resembles myelodysplastic syndromes with-RS/SF3B1 mutation in terms of phenotype and prognosis.

Chronic myelomonocytic leukemia (CMML) and myelodysplastic syndromes (MDS) with ring sideroblasts (RS) or SF3B1 mutation (MDS-RS/SF3B1) differ in many clinical features, but share others, such as anemia. RS and SF3B1 mutation can also be found in CMML. We compared CMML with and without RS/SF3B1 and MDS-RS/SF3B1 considering the criteria established by the 2022 World Health Organization classification. A total of 815 patients were included (CMML, n=319, CMML-RS/SF3B1, n=172 and MDS-RS/SF3B1, n=324). The percentage of RS was ≥15% in almost all CMML-RS/SF3B1 patients (169, 98.3%) and most (125, 72.7%) showed peripheral blood monocyte counts between 0.5 and 0.9 x109/L and low risk prognostic categories. CMML-RS/SF3B1 differed significantly from classical CMML in the main clinical characteristics, whereas it resembled MDS-RS/SF3B1. At a molecular level, CMML and CMML-RS/SF3B1 had a significantly higher frequency of mutations in TET2 (mostly multi-hit) and ASXL1 (p=0.013) and CMML had a significantly lower frequency of DNMT3A and SF3B1 mutations compared to CMML/MDS-RS/SF3B1. Differences in the median overall survival among the three groups were statistically significant: 6.75 years (95% confidence interval [CI] 5.41-8.09) for CMML-RS/SF3B1 vs. 3.17 years (95% CI 2.56-3.79) for CMML vs. 16.47 years (NA) for MDS-RS/SF3B1, p<0.001. Regarding patients with CMML and MDS, both with SF3B1 mutation, survival did not significantly differ. CMML had a higher risk of transformation to acute myeloid leukemia (24% at 8 years, 95%CI 19%-30%). CMML-RS/SF3B1 mutation resembles MDS-RS/SF3B1 in terms of phenotype and clearly differs from CMML. The presence of ≥15% RS and/or SF3B1 in CMML is associated with a low monocyte count. SF3B1 mutation clearly improves the prognosis of CMML.

A comparison of WHO-5 and ICC classifications in a series of myeloid neoplasms, considerations for hematopathologists and molecular pathologists

ObjectivesThe International Consensus Classification (ICC) and 5th Edition of the World Health Organization Classification (WHO-5) made substantive updates to the classification of myeloid neoplasms. This study compares the systems in a series of myeloid neoplasms with increased blasts, analyzing implications for diagnostic workflow and reporting. MethodsBone marrow biopsies categorized as myelodysplastic syndrome with excess blasts (MDS-EB) or acute myeloid leukemia (AML) by WHO-R4 were identified. Results of morphology review, karyotype, fluorescence in situ hybridization, and next-generation sequencing were compiled. Cases were retrospectively re-classified by WHO-5 and ICC. Results46 cases were reviewed. 28 cases (61 %) had ≥20 % blasts, with the remaining cases having 5–19.5 % blasts. The most common differences in classification were 1) the designation of MDS versus MDS/AML (10/46, 22 %) for cases with 10–19 % blasts and 2) the ICC's designation of TP53 variants as a separate classifier for AML (8/46, 17 %). Bi-allelic/multi-hit TP53 alterations were identified in 15 cases (33 %). Variants of potential germline significance were identified in 29 (63 %) cases. ConclusionsWhile terminology differences between WHO-5 and ICC exist, both systems invoke similar opportunities for improved reporting: standardized classification of pathogenic variants (notably TP53), streamlined systems to evaluate for potential germline variants, and integrated reporting of morphologic and genetic data.

The 2021 World Health Organization Central Nervous System Tumor Classification: The Spectrum of Diffuse Gliomas.

The 2021 edition of the World Health Organization (WHO) classification of central nervous system tumors introduces significant revisions across various tumor types. These updates, encompassing changes in diagnostic techniques, genomic integration, terminology, and grading, are crucial for radiologists, who play a critical role in interpreting brain tumor imaging. Such changes impact the diagnosis and management of nearly all central nervous system tumor categories, including the reclassification, addition, and removal of specific tumor entities. Given their pivotal role in patient care, radiologists must remain conversant with these revisions to effectively contribute to multidisciplinary tumor boards and collaborate with peers in neuro-oncology, neurosurgery, radiation oncology, and neuropathology. This knowledge is essential not only for accurate diagnosis and staging, but also for understanding the molecular and genetic underpinnings of tumors, which can influence treatment decisions and prognostication. This review, therefore, focuses on the most pertinent updates concerning the classification of adult diffuse gliomas, highlighting the aspects most relevant to radiological practice. Emphasis is placed on the implications of new genetic information on tumor behavior and imaging findings, providing necessary tools to stay abreast of advancements in the field. This comprehensive overview aims to enhance the radiologist's ability to integrate new WHO classification criteria into everyday practice, ultimately improving patient outcomes through informed and precise imaging assessments.

Histopathologic Features and Differential Diagnosis in Challenging Cases of Nodular Lymphocyte Predominant B-cell Lymphoma/Nodular Lymphocyte Predominant Hodgkin Lymphoma.

Nodular lymphocyte predominant Hodgkin lymphoma was termed "nodular lymphocyte predominant B-cell lymphoma" in the International Consensus Classification (ICC), to emphasize clinical and biological differences from classic Hodgkin lymphoma (CHL). The abbreviation "NLP" represents both terms in the ICC and World Health Organization classifications. Variations in the growth pattern, originally reported as Fan patterns A-F, are designated as either grade 1 or grade 2 in the ICC. NLP is uncommon, and in some cases an accurate diagnosis is challenging. The objectives of this article were to review the histopathologic features of NLP and the differential diagnosis from other key entities including de novo T-cell/histiocyte-rich large B-cell lymphoma (THRLBL) and lymphocyte-rich classic Hodgkin lymphoma (LRCHL). Histologically, NLP Fan pattern E (THRLBL-like) can be indistinguishable from de novo THRLBL. However, focal nodular areas, clustering of tumor cells, presence of few admixed small B-cells or FDC meshworks, and T-cell rosettes favor NLP Fan pattern E and argue against de novo THRLBL. NLP may also be confused with LRCHL. Patients with NLP are younger than those with LRCHL, and LRCHL may show mediastinal involvement. In LRCHL, the nodular pattern often contains eccentrically located small regressed germinal centers and intact small dense FDC meshworks, in contrast to the expanded, and fragmented FDC meshworks in NLP. Neoplastic cells that are positive for CD30 and CD15 but negative for CD20 and CD79a are characteristic of LRCHL. Additionally, Fascin and Gata3 are commonly positive in LRCHL but usually negative in NLP.

Pediatric-type diffuse low-grade glioma with T2-FLAIR mismatch sign: a case report and literature review.

Pediatric-type diffuse low-grade gliomas are a new entity that was introduced in the fifth edition of the World Health Organization Classification of Tumors of the Central Nervous System, which was published in 2021. Notably, the information regarding the radiophenotypes of this new entity is limited. T2-FLAIR mismatch sign has been mostly studied in adult-type diffuse gliomas so far. We aimed to present more pediatric cases for future research about T2-FLAIR mismatch signs in pediatric-type diffuse low-grade gliomas. The current study presents a case of a 2-year-old boy who has a subcortical tumor at the right precentral frontal region. This tumor exhibited a T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign that was identified as specific for isocitrate dehydrogenase (IDH)-mutant 1p/19q non-co-deleted astrocytomas. The tumor was pathologically identified as pediatric-type diffuse low-grade gliomas, and it tested negative for IDH-1 immunohistochemistry. The whole-exome sequencing of tumor tissue revealed negative results for IDH mutation, 1p/19q co-deletion, MYB rearrangement, and all other potential pathogenic mutations. The T2-FLAIR mismatch sign may not be 100% specific for IDH-mutant gliomas, especially in children, and researchers must further investigate the pathophysiology of the T2-FLAIR mismatch sign in brain tumors and the radiophenotypes of entities of pediatric brain tumors.

Sporadic Hybrid Nerve Sheath Tumour Arising from a Vestibulocochlear Nerve: A rare Case Report

Hybrid peripheral nerve sheath tumors (HPNST) were first included in the 4th edition of the World Health Organization (WHO) Classification of Central Nervous System in 2016. These tumors are a combination of schwannoma and neurofibroma, and are typically found in the limbs, trunk, and soft tissues. In this case report, we present a rare intracranial localization of neurofibroma/schwannoma with histological examination. Our patient was a 36-year-old man without any tumor genetic syndromes. The tumor measured 1.6 × 1.1 cm and was completely excised. The pathology report showed no significant nuclear atypia, mitotic activity, or necrosis. At the time of writing, the patient is alive and well with no recurrence. It is important to note that HPNSTs are usually benign tumors, but can occur in various locations, including the intracranial region. Further studies with a larger number of cases are needed to determine the exact pathogenetic basis of these tumors.

Interpretation of T-cell and NK-cell lymphoid proliferations and lymphomas in the 5th edition of the WHO classification of haematolymphoid tumours

The 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumours used the hierarchical system to classify T-cell and NK-cell lymphoid proliferations and lymphomas (T/NK-LPD/LYM) based on research advances and clinicopathological characteristics of the diseases. In this edition of classification, tumour-like lesions were included, some tumors were added/deleted, the names or terms of certain diseases were refined, and the diagnostic criteria or subtypes of some diseases were revised. This group of diseases was reintegrated from non-clonal hyperplasia to highly aggressive lymphoma, which would further reflect the nature of T/NK-LPD/LYM and benefit to clinical application.

Delineating the Biomarker Potential and Therapeutic Significance of MicroRNAs in IDH-wildtype Glioblastoma as Defined by the WHO CNS5 Criteria

The World Health Organization (WHO) CNS5 classification, updated in 2021, has brought about a significant transformation in the diagnosis and treatment of IDH-wildtype glioblastoma, a subgroup of aggressive brain tumors. This new system, which incorporates molecular markers alongside traditional tissue analysis, provides a more refined approach that facilitates the identification of distinct glioblastoma subtypes with unique genetic profiles. Examples of these subtypes include IDH-mutant astrocytoma, IDH-mutant and 1p/19q-deleted oligodendroglioma, and IDH-wildtype glioblastoma. Despite advancements in genetics and targeted therapies, the treatment of these malignant tumors remains an ongoing quest. Therefore, the need for more specific diagnostic and therapeutic approaches is undeniable. MicroRNAs (miRNAs) are emerging as molecules that molecular biology has brought to the medical world in this context. These tiny molecules act as master regulators of gene expression and hold immense potential for glioblastoma diagnosis, prognosis prediction, and biomarker development. Recent research has highlighted the potential of miRNAs as therapeutic strategies, attracting scientific interest to this point. This review examines the current relationships of miRNAs in the context of IDH-wildtype glioblastoma within the framework of the WHO CNS5 classification. Utilizing extensive databases, this article investigates the intricate relationship between genetic abnormalities defined in the latest WHO classification and dysregulated miRNAs. By analyzing proposed molecular biomarkers and associated miRNA dysregulation, we aim to pave the way for the development of personalized miRNA-based therapies for this aggressive cancer type.

T2-FLAIR mismatch sign predicts DNA methylation subclass and CDKN2A/B status in IDH-mutant astrocytomas.

DNA methylation profiling stratifies isocitrate dehydrogenase (IDH)-mutant astrocytomas into methylation low-grade and high-grade groups. We investigated the utility of the T2-FLAIR mismatch sign for predicting DNA methylation grade and cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) homozygous deletion, a molecular biomarker for grade 4 IDH-mutant astrocytomas, according to the 2021 World Health Organization (WHO) classification. Preoperative MRI scans of IDH-mutant astrocytomas subclassified by DNA methylation profiling (n=71) were independently evaluated by two radiologists for the T2-FLAIR mismatch sign. The diagnostic utility of T2-FLAIR mismatch in predicting methylation grade, CDKN2A/B status, copy number variation, and survival was analyzed. The T2-FLAIR mismatch sign was present in 21 of 45 (46.7%) methylation low-grade and 1 of 26 (3.9%) methylation high-grade cases (p<0.001), resulting in 96.2% specificity, 95.5% positive predictive value, and 51.0% negative predictive value for predicting low methylation grade. The T2-FLAIR mismatch sign was also significantly associated with intact CDKN2A/B status (p=0.028) with 87.5% specificity, 86.4% positive predictive value, and 42.9% negative predictive value. Overall multivariable Cox analysis showed that retained CDKN2A/B status remained significant for PFS (p=0.01). Multivariable Cox analysis of the histologic grade 3 subset, which was nearly evenly divided by CDKN2A/B status, CNV, and methylation grade, showed trends toward significance for DNA methylation grade with OS (p=0.045) and CDKN2A/B status with PFS (p=0.052). The T2-FLAIR mismatch sign is highly specific for low methylation grade and intact CDKN2A/B in IDH-mutant astrocytomas.