Endometrial stromal tumor with whorling and GREB1::CTNNB1 fusion: expanding the knowledge on a recently described entity.

Endometrial stromal tumors with whorling and CTNNB1 rearrangement (ESTW-CTNNB1) are recently described gynecological mesenchymal neoplasms with unique clinicopathological and molecular features. To date, only four of these tumors have been reported. Herein, we describe a case of ESTW-CTNNB1 in a 67-year-old woman.

Age-linked DNA methylation and gene expression patterns in parameningeal head and neck alveolar rhabdomyosarcoma reveal CDK9 as a promising therapeutic target.

Background: Alveolar rhabdomyosarcoma (ARMS) primarily affects children in the first decade of life, but it can also occur during adolescence, typically with a more favorable prognosis. This study aimed to explore differences in DNA methylation (DNAm) and gene expression profiles that may account for the worse prognosis in younger patients; and to investigate possible new therapeutic targets.

Methods: We conducted whole-genome DNAm and transcriptome analyses on 10 parameningeal head and neck ARMS patients, including 4 patients under 1 year old and 6 over 10 years old.

EGFR-KDD Myofibroblastic Neoplasm or Congenital Peribronchial Myofibroblastic Tumor (CPMT)? Report of a Congenital Myofibroblastic Neoplasm With Unusual Histologic Features.

EGFR-kinase-domain duplication (KDD) has been reported in Infantile fibrosarcoma-like myofibroblastic tumors and cellular mesoblastic nephroma. We report a pulmonary neoplasm with EGFR-(KDD) and infantile fibrosarcoma-like histologic features in a female infant with an unusual clinical and histologic evolution, characterized by persistent disease with morphologic features of Congenital Peribronchial Myofibroblastic Tumor (CPMT) after chemotherapy and targeted therapy. The CPMT morphology with EGFR-KDD in the post-therapy specimen might be an evolution induced by the treatment, which suggests the hypothesis that CPMT is part of the morphologic spectrum of infantile fibrosarcoma/cellular mesoblastic nephroma.

DEK::AFF2 rearranged neoplasm with undifferentiated morphology and neuroendocrine phenotype in a pediatric patient.

The advent of next-generation sequencing (NGS) has greatly enhanced the identification of morphologically and/or phenotypically unusual neoplasms. We report an undifferentiated carcinoma with a DEK::AFF2 fusion in a 13-year-old female from the head and neck region. DEK::AFF2 rearranged non-keratinizing squamous cell carcinoma (NKSCC) has been recognized as a distinct entity in the WHO classification of head and neck tumors, typically affecting adults.

DNA methylation profiling from cerebrospinal fluid as a diagnostic tool for pineoblastoma.

Pineoblastoma is a rare and aggressive malignancy that often affects pediatric populations. Accurate diagnosis is challenging due to histological overlap with other central nervous system tumors and limited molecular data. DNA methylation profiling and analysis of circulating tumor DNA (derived from both cell dissemination as well as cell-free- cfDNA) in cerebrospinal fluid (CSF) are emerging tools for precise tumor classification, in the field of pediatric central nervous system tumors.

Novel PDGFRB Gene Fusions in Two Cases of Infantile Myofibromatosis.

Infantile myofibromatosis (IM) comprises a wide clinical spectrum, ranging from solitary or multicentric lesions to generalized life-threatening forms. IM is mostly linked to germline or somatic heterozygous mutations in the PDGFRβ tyrosine kinase, encoded by the PDGFRB gene. Treatments for IM range from wait and see approach to systemic chemotherapy, according to the clinical context.

Identification of a novel SH3PXD2B::FER fusion in a case of plexiform myofibroblastic tumor and review of the literature.

Fibroblastic/myofibroblastic tumors encompass a wide spectrum of lesions. Among them, plexiform myofibroblastoma (PM) represents a rare and distinctive entity recently described as mostly occurring in children and with a favorable prognosis. Histologically, PM shows SMA, CD34, and desmin expression in most cases, while it is negative for β-catenin and S100.

Reappraisal of soft tissue myoepithelial tumors by DNA methylation profiling reveals an epigenetically distinct group of mostly fusion-driven neoplasms.

Soft tissue myoepithelial tumors (METs) are diagnostically challenging tumors that require careful histologic and immunohistochemical characterization for accurate classification. Nearly half of METs show recurrent EWSR1 or FUS gene rearrangements with a diverse set of fusion partners. The diversity of fusion partners and lack of known driver abnormalities in many cases raises the question of whether METs represent a uniformly distinct tumor entity.

LMNA::NTRK1 and PRDX1::NTRK1 Atypical Spitz Tumor: A Report of Two Additional Cases With Histological, Immunohistochemical, and Molecular Insights.

Over the past decade, advancements in molecular biology have contributed to changes in the diagnostic classification of Spitz neoplasms, including Spitz nevi, atypical Spitz tumors, and Spitz melanomas. The recent World Health Organization classification of skin tumors identifies fusion kinases, including NTRK1, NTRK2, and NTRK3, as critical drivers of these lesions. New fusion genes have continued to expand the spectrum of known molecular alterations, particularly within the category of Spitz NTRK-rearranged lesions.

NTRK3-EML4-rearranged spindle cell tumor with co-expression of S100 and CD34: an unusual mesenchymal tumor in the spectrum of the bland-looking spindle cell lesions of the oral cavity.

A novel category of spindle cell tumors characterized by Neurotrophic Tyrosine Receptor Kinase (NTRK) rearrangements with a dual immunoreactivity for S-100 and CD34 has emerged in the last years as a distinct entity among soft tissue neoplasms. These genetic alterations lead to the continuous activation of NTRK genes, driving tumorigenesis and offering a unique prospect for targeted therapy. We herein present a rare case of NTRK3-rearranged spindle cell tumor with a hitherto unreported gene fusion involving the exon 14 of NTRK3 with the exon 2 of Echinoderm Microtubule-Associated Protein-Like 4, arising in the head and neck region.

Spindle Cell Lesions with Oncogenic EGFR Kinase Domain Aberrations: Expanding the Spectrum of Protein Kinase-Related Mesenchymal Tumors.

EGFR aberrations are reported in a subset of myofibroblastic lesions with kinase domain duplication (EGFR-KDD) and exon 20 mutations being assigned to infantile fibrosarcomas (IFS), mesoblastic nephroma, and fibrous hamartoma of infancy (FHI), respectively. In this retrospective study, we correlated molecular findings with the histomorphology of 14 myofibroblastic lesions harboring such genetic changes identified by NGS. We additionally performed DNA methylation profiling (DNAmp) and immunohistochemistry.

A Novel NUTM1-NSMCE2 Fusion Gene in a Pediatric Chest NUT Carcinoma.

Nuclear protein of the testis carcinoma is an exceedingly rare and poorly differentiated carcinoma characterized by BDR4::NUTM1 gene translocation. Typically, the tumor affects young adults, and no standardized recommendations for therapeutic management have been available since 2022; the clinical course remains mostly dismal. We report the successful multimodal treatment of a 13-year-old boy affected by a primary chest NUT-carcinoma with a novel NUTM1 rearrangement that remains in complete continuous remission at 30 months from diagnosis.

RAF1 gene fusions are recurrent driver events in infantile fibrosarcoma-like mesenchymal tumors.

Infantile fibrosarcomas (IFS) and congenital mesoblastic nephroma (CMN) are rare myofibroblastic tumors of infancy and early childhood commonly harboring the ETV6::NTRK3 gene fusion. IFS/CMN are considered as tumors with an 'intermediate prognosis' as they are locally aggressive, but rarely metastasize, and generally have a favorable outcome. A fraction of IFS/CMN-related neoplasms are negative for the ETV6::NTRK3 gene rearrangement and are characterized by other chimeric proteins promoting MAPK signaling upregulation.

Clinicopathological and molecular landscape of 5-year IDH-wild-type glioblastoma survivors: A multicentric retrospective study.

Five-year glioblastoma (GBM) survivors (LTS) are the minority of the isocitrate dehydrogenase (IDH)-wild-type GBM patients, and their molecular fingerprint is still largely unexplored. This multicenter retrospective study analyzed a large LTS-GBM cohort from nine Italian institutions and molecularly characterized a subgroup of patients by mutation, DNA methylation (DNAm) and copy number variation (CNV) profiling, comparing it to standard survival GBM. Mutation scan allowed the identification of pathogenic variants in most cases, showing a similar mutational spectrum in both groups, and highlighted TP53 as the most commonly mutated gene in the LTS group.

CNS tumor with CREBBP::BCORL1 Fusion and pathogenic mutations in BCOR and CREBBP: expanding the spectrum of BCOR-altered tumors.

The fifth edition of the World Health Organization (WHO) classification of central nervous system (CNS) tumors introduced the new tumor type CNS tumor with BCOR internal tandem duplication (ITD), characterized by a distinct DNA methylation profile and peculiar histopathological features, including a circumscribed growth pattern, ependymoma-like perivascular pseudorosettes, microcystic pattern, absent or focal GFAP immunostaining, OLIG2 positivity, and BCOR immunoreactivity. We describe a rare case of a CNS tumor in a 45-year-old man with histopathological and immunohistochemical features overlapping the CNS tumor with BCOR internal tandem duplication (ITD) but lacking BCOR immunostaining and BCOR ITD. Instead, the tumor showed CREBBP::BCORL1 fusion and pathogenic mutations in BCOR and CREBBP, along with a DNA methylation profile matching the "CNS tumor with EP300:BCOR(L1) fusion" methylation class.

Malignant peripheral nerve sheath tumor (MPNST) and MPNST-like entities are defined by a specific DNA methylation profile in pediatric and juvenile population.

Background: Malignant peripheral nerve sheath tumors (MPNSTs) account for 3-10% of pediatric sarcomas, 50% of which occur in neurofibromatosis type 1 (NF1). Sporadic MPNSTs diagnosis may be challenging due to the absence of specific markers, apart from immunohistochemical H3K27me3 loss. DNA methylation (DNAm) profiling is a useful tool for brain and mesenchymal neoplasms categorization, and MPNSTs exhibit a specific DNAm signature.

Bi-allelic genetic variants in the translational GTPases GTPBP1 and GTPBP2 cause a distinct identical neurodevelopmental syndrome.

The homologous genes GTPBP1 and GTPBP2 encode GTP-binding proteins 1 and 2, which are involved in ribosomal homeostasis. Pathogenic variants in GTPBP2 were recently shown to be an ultra-rare cause of neurodegenerative or neurodevelopmental disorders (NDDs). Until now, no human phenotype has been linked to GTPBP1.

Intrathoracic synovial sarcoma with BRAF V600E mutation.

We report a case of 15-year-old boy with intrathoracic synovial sarcoma who relapsed after standard chemotherapy, surgery and radiotherapy. The molecular analysis of the tumour identified a BRAF V600E mutation at time of progression of relapsed disease under third line systemic treatment. This mutation is commonly seen in melanomas and papillary thyroid cancers, but less prevalent (typically <5%) across a variety of other cancer types.

Intracranial mesenchymal tumor with (novel) COX14::PTEN rearrangement.

Mesenchymal tumors of the central nervous system (CNS) include numerous entities, with different pathological features and biological behavior. Mesenchymal non-meningothelial tumors are rare and comprise neoplasms that are exclusive to the CNS or show peculiar features when occurring in the CNS compared with other sites. Within this group there are three new entities, classified on the basis of specific molecular alterations and included in the 5th edition of the WHO Classification of CNS Tumors: primary intracranial sarcoma; DICER1-mutant; CIC-rearranged sarcoma; intracranial mesenchymal tumor, FET::CREB fusion-positive.

Defective peripheral B cell selection in common variable immune deficiency patients with autoimmune manifestations.

Common variable immune deficiency (CVID) is a heterogeneous disorder characterized by recurrent infections, low levels of serum immunoglobulins, and impaired vaccine responses. Autoimmune manifestations are common, but B cell central and peripheral selection mechanisms in CVID are incompletely understood. Here, we find that receptor editing, a measure of central tolerance, is increased in transitional B cells from CVID patients and that these cells have a higher immunoglobulin κ:λ ratio in CVID patients with autoimmune manifestations than in those with infection only.