Neurenteric cyst at the dorsal craniocervical junction in a child: Case report

Neurenteric cysts, also known as enterogenous cysts, are uncommon, benign, congenital lesions that usually occur in the posterior mediastinum but can be seen at any level of the neuraxis. Here, we report a pediatric patient with a neurenteric cyst in the dorsal craniocervical junction as the only third reported pediatric case in the literature in this rare location, and describe the clinical course and pathologic findings with a review of the literature on this rare entity

Intracranial mesenchymal tumor with FET-CREB fusion - A unifying diagnosis for the spectrum of intracranial myxoid mesenchymal tumors and angiomatoid fibrous histiocytoma-like neoplasms

Intracranial mesenchymal tumors with FET-CREB fusions are a recently described group of neoplasms in children and young adults characterized by fusion of a FET family gene (usually EWSR1, but rarely FUS) to a CREB family transcription factor (ATF1, CREB1, or CREM), and have been variously termed intracranial angiomatoid fibrous histiocytoma or intracranial myxoid mesenchymal tumor. The clinical outcomes, histologic features, and genomic landscape are not well defined. Here we studied twenty patients with intracranial mesenchymal tumors proven to harbor FET-CREB fusion by next-generation sequencing (NGS). The 16 female and 4 male patients had a median age of 14 years (range 4-70). Tumors were uniformly extra-axial or intraventricular and located at the cerebral convexities (n=7), falx (2), lateral ventricles (4), tentorium (2), cerebellopontine angle (4), and spinal cord (1). NGS demonstrated that 8 tumors harbored EWSR1-ATF1 fusion, 7 had EWSR1-CREB1, 4 had EWSR1-CREM, and 1 had FUS-CREM. Tumors were uniformly well-circumscribed and typically contrast-enhancing with solid and cystic growth. Tumors with EWSR1-CREB1 fusions more often featured stellate/spindle cell morphology, mucin-rich stroma, and hemangioma-like vasculature compared to tumors with EWSR1-ATF1 fusions that most often featured sheets of epithelioid cells with mucin-poor collagenous stroma. These tumors demonstrated polyphenotypic immunoprofiles with frequent positivity for desmin, EMA, CD99, MUC4, and synaptophysin, but absence of SSTR2A, myogenin, and HMB45 expression. There was a propensity for local recurrence with a median progression-free survival of 12 months and a median overall survival of greater than 60 months, with three patients succumbing to disease (all with EWSR1-ATF1 fusions). In combination with prior case series, this study provides further insight into intracranial mesenchymal tumors with FET-CREB fusion, which represent a distinct group of CNS tumors encompassing both intracranial myxoid mesenchymal tumor and angiomatoid fibrous histiocytoma-like neoplasms

Glioneuronal tumor with ATRX alteration, kinase fusion and anaplastic features (GTAKA): a molecularly distinct brain tumor type with recurrent NTRK gene fusions

Glioneuronal tumors are a heterogenous group of CNS neoplasms that can be challenging to accurately diagnose. Molecular methods are highly useful in classifying these tumors-distinguishing precise classes from their histological mimics and identifying previously unrecognized types of tumors. Using an unsupervised visualization approach of DNA methylation data, we identified a novel group of tumors (n = 20) that formed a cluster separate from all established CNS tumor types. Molecular analyses revealed ATRX alterations (in 16/16 cases by DNA sequencing and/or immunohistochemistry) as well as potentially targetable gene fusions involving receptor tyrosine-kinases (RTK; mostly NTRK1-3) in all of these tumors (16/16; 100%). In addition, copy number profiling showed homozygous deletions of CDKN2A/B in 55% of cases. Histological and immunohistochemical investigations revealed glioneuronal tumors with isomorphic, round and often condensed nuclei, perinuclear clearing, high mitotic activity and microvascular proliferation. Tumors were mainly located supratentorially (84%) and occurred in patients with a median age of 19 years. Survival data were limited (n = 18) but point towards a more aggressive biology as compared to other glioneuronal tumors (median progression-free survival 12.5 months). Given their molecular characteristics in addition to anaplastic features, we suggest the term glioneuronal tumor with ATRX alteration, kinase fusion and anaplastic features (GTAKA) to describe these tumors. In summary, our findings highlight a novel type of glioneuronal tumor driven by different RTK fusions accompanied by recurrent alterations in ATRX and homozygous deletions of CDKN2A/B. Targeted approaches such as NTRK inhibition might represent a therapeutic option for patients suffering from these tumors

CNS intravascular large cell lymphoma in a patient with autoimmune hemolytic anemia.

Intravascular large cell lymphoma (IVLCL) is a rare disease characterized by proliferation of malignant lymphocytes within the small blood vessel lumens. The association of IVLCL with autoimmune hemolytic anemia (AIHA) has been described in a single case report, but the true prevalence of this co-occurrence is not known because of declining autopsy rates. Here, we report a case of a 41-year-old woman who carried a diagnosis of AIHA for 2 years, with repeated hemolytic episodes that were initially well controlled with immunomodulatory treatment. At her last presentation, the patient developed rapidly progressive neurologic symptoms and leukoencephalopathy on MRI; she died 4 weeks later with a clinical impression of thrombotic microangiopathy, a known complication of AIHA. At autopsy, the brain showed widespread platelet thrombi and intraparenchymal hemorrhages characteristic of this disorder. In addition, there was evidence of a clinically unsuspected IVLCL, most likely of B-cell lineage. This case illustrates a potential association between IVLCL and AIHA, highlights the need for broad differential diagnosis in cases with atypical disease presentation or progression, and underlines the importance of autopsy in establishing the full cause of morbidity and mortality

CNS intravascular large cell lymphoma in a patient with autoimmune hemolytic anemia.

Intravascular large cell lymphoma (IVLCL) is a rare disease characterized by proliferation of malignant lymphocytes within the small blood vessel lumens. The association of IVLCL with autoimmune hemolytic anemia (AIHA) has been described in a single case report, but the true prevalence of this co-occurrence is not known because of declining autopsy rates. Here, we report a case of a 41-year-old woman who carried a diagnosis of AIHA for 2 years, with repeated hemolytic episodes that were initially well controlled with immunomodulatory treatment. At her last presentation, the patient developed rapidly progressive neurologic symptoms and leukoencephalopathy on MRI; she died 4 weeks later with a clinical impression of thrombotic microangiopathy, a known complication of AIHA. At autopsy, the brain showed widespread platelet thrombi and intraparenchymal hemorrhages characteristic of this disorder. In addition, there was evidence of a clinically unsuspected IVLCL, most likely of B-cell lineage. This case illustrates a potential association between IVLCL and AIHA, highlights the need for broad differential diagnosis in cases with atypical disease presentation or progression, and underlines the importance of autopsy in establishing the full cause of morbidity and mortality

A novel GIT2-BRAF fusion in pilocytic astrocytoma

Abstract Background KIAA1549-BRAF fusion is the most common genetic event in pilocytic astrocytoma (PA), and leads to activation of the mitogen activated protein kinase (MAPK) signaling pathway. Fusions of BRAF with other partner genes, as well as other genetic alterations not involving BRAF but also leading to MAPK pathway activation have been described rarely. Case presentation We present a new fusion partner in the low-grade glioma of a 10-year-old male, who presented with headaches and recent episodes of seizures. Magnetic resonance imaging (MRI) demonstrated a right temporal lobe tumor. Histological and immunohistochemical evaluation, and a next generation sequencing assay (Oncopanel, Illumina, 500 genes) including breaKmer analysis for chromosomal rearrangements were performed. Histology was remarkable for a low-grade glioma composed of mildly atypical astrocytes with piloid processes, in a focally microcystic background. Mitoses were not seen; unequivocal Rosenthal fibers or eosinophilic granular bodies were absent. The tumor was positive for OLIG2 and GFAP and negative for BRAF V600E and IDH1 R132H mutant protein immunostains. Oncopanel showed low SOX2 (3q26.33) copy number gain, and no gains at 7q34. There were no significant single nucleotide variants. BreaKmer detected a GIT2-BRAF fusion with loss of BRAF exons 1–8. The integrated diagnosis was low-grade glioma with piloid features, most consistent with pilocytic astrocytoma, WHO grade I. Conclusion GIT2-BRAF fusion has not been reported in the literature in any tumor. Given that the BRAF sequence deleted is identical to that seen in other fusion events in PA, it most likely acts as tumor driver by activation of the MAPK pathway

Additional file 1: Figure S1. of A novel GIT2-BRAF fusion in pilocytic astrocytoma

Representative image of BreaKmer interface illustrating GIT2-BRAF translocation. Sequenced contigs corresponding to BRAF are gray, with contiguous rainbow reads corresponding to bases that are part of GIT2. Sequence details of the translocation are shown at the bottom of the schematic (TIFF 25908 kb