Expanding the clinicopathologic spectrum and genomic landscape of tumors with SMARCA2/4::CREM fusions.

CREB gene family (ATF1, CREB1, CREM) fusions with either EWSR1 or FUS gene partners drive the pathogenesis of a wide range of neoplasms, including various soft tissue tumors, intracranial myxoid mesenchymal tumors (IMMTs), hyalinizing clear cell carcinoma (HCCC), and rare mesotheliomas. Recently, a SMARCA2::CREM fusion was reported in one case each of IMMT and HCCC. In this study, we expand the clinicopathologic and molecular spectrum of these neoplasms by describing three additional cases with SMARCA2::CREM and one with a novel SMARCA4::CREM fusion, highlighting the recurrent potential of additional CREB gene fusion partners beyond FET family members. To evaluate if these fusions define a new pathologic entity, we performed a comprehensive genomic and methylation analysis and compared the results to other related tumors. Tumors occurred in children and young adults (median age 20 years) and spanned a broad anatomic distribution, including soft tissue, intracranial, head and neck, and prostatic urethra. Microscopically, the tumors shared an undifferentiated round to epithelioid cell phenotype and a hyalinized fibrous stroma. Immunohistochemically, a polyphenotypic profile was observed, with variable expression of SOX10, desmin, and/or epithelial markers. No targetable genomic alterations were found using panel-based DNA sequencing. By DNA methylation and transcriptomic analyses, tumors grouped closely to FET::CREB entities, but not with SMARCA4/SMARCB1-deficient tumors. High expression of CREM by immunohistochemistry was also documented in these tumors. Patients experienced local recurrence (n = 2), locoregional lymph node metastases (n = 2), and an isolated visceral metastasis (n = 1). Overall, our study suggests that SMARCA2/4::CREM fusions define a distinct group of neoplasms with round cell to epithelioid histology, a variable immunoprofile, and a definite risk of malignancy. Larger studies are needed to further explore the pathogenetic relationship with the FET::CREB family of tumors. © 2024 The Pathological Society of Great Britain and Ireland.

Clinical Validation of Stimulated Raman Histology for Rapid Intraoperative Diagnosis of Central Nervous System Tumors.

Stimulated Raman histology (SRH) is an ex vivo optical imaging method that enables microscopic examination of fresh tissue intraoperatively. The conventional intraoperative method uses frozen section analysis, which is labor and time intensive, introduces artifacts that limit diagnostic accuracy, and consumes tissue. SRH imaging allows rapid microscopic imaging of fresh tissue, avoids tissue loss, and enables remote telepathology review. This improves access to expert neuropathology consultation in both low- and high-resource practices. We clinically validated SRH by performing a blinded, retrospective two-arm telepathology study to clinically validate SRH for telepathology at our institution. Using surgical specimens from 47 subjects, we generated a data set composed of 47 SRH images and 47 matched whole slide images (WSIs) of formalin-fixed, paraffin-embedded tissue stained with hematoxylin and eosin, with associated intraoperative clinicoradiologic information and structured diagnostic questions. We compared diagnostic concordance between WSI and SRH-rendered diagnoses. Also, we compared the 1-year median turnaround time (TAT) of intraoperative conventional neuropathology frozen sections with prospectively rendered SRH-telepathology TAT. All SRH images were of sufficient quality for diagnostic review. A review of SRH images showed high accuracy in distinguishing glial from nonglial tumors (96.5% SRH vs 98% WSIs) and predicting final diagnosis (85.9% SRH vs 93.1% WSIs). SRH-based diagnosis and WSI-permanent section diagnosis had high concordance (κ = 0.76). The median TAT for prospectively SRH-rendered diagnosis was 3.7 minutes, approximately 10-fold shorter than the median frozen section TAT (31 minutes). The SRH-imaging procedure did not affect ancillary studies. SRH generates diagnostic virtual histologic images with accuracy comparable to conventional hematoxylin and eosin-based methods in a rapid manner. Our study represents the largest and most rigorous clinical validation of SRH to date. It supports the feasibility of implementing SRH as a rapid method for intraoperative diagnosis complementary to conventional pathology laboratory methods.

Endothelium-Independent Primitive Myxoid Vascularization Creates Invertebrate-Like Channels to Maintain Blood Supply in Optic Gliomas.

Optic gliomas are brain tumors characterized by slow growth, progressive loss of vision, and limited therapeutic options. Optic gliomas contain various amounts of myxoid matrix, which can represent most of the tumor mass. We sought to investigate biological function and protein structure of the myxoid matrix in optic gliomas to identify novel therapeutic targets. We reviewed histological features and clinical imaging properties, analyzed vasculature by immunohistochemistry and electron microscopy, and performed liquid chromatography-mass spectrometry on optic gliomas, which varied in the amount of myxoid matrix. We found that although subtypes of optic gliomas are indistinguishable on imaging, the microvascular network of pilomyxoid astrocytoma, a subtype of optic glioma with abundant myxoid matrix, is characterized by the presence of endothelium-free channels in the myxoid matrix. These tumors show normal perfusion by clinical imaging and lack histological evidence of hemorrhage organization or thrombosis. The myxoid matrix is composed predominantly of the proteoglycan versican and its linking protein, a vertebrate hyaluronan and proteoglycan link protein 1. We propose that pediatric optic gliomas can maintain blood supply without endothelial cells by using invertebrate-like channels, which we termed primitive myxoid vascularization. Enzymatic targeting of the proteoglycan versican/hyaluronan and proteoglycan link protein 1 rich myxoid matrix, which is in direct contact with circulating blood, can provide novel therapeutic avenues for optic gliomas of childhood.

Progressive multifocal leukoencephalopathy after allogeneic stem cell transplantation: Case report and review of the literature.

Progressive multifocal leukoencephalopathy (PML) is a rare, yet typically fatal complication of allogeneic stem cell transplantation. It is caused by reactivation of the John Cunningham (JC) virus in an immunocompromised host. This report describes an unfortunate case of PML in a recipient of an allogeneic stem cell transplant for acute myelogenous leukemia. The JC virus was undetectable in the patient's cerebrospinal fluid by polymerase chain reaction (PCR); however, a positive diagnosis was made after a brain biopsy. This and other published cases demonstrate that recipients of allogeneic stem cells can develop PML. Moreover, early diagnosis of the disease is often difficult and, as demonstrated in this case, screening with PCR does not appear to have strong diagnostic significance. With no effective treatment presently available, restoration of immune function is the only intervention that can affect prognosis. Further prospective studies are needed to understand the pathophysiology and treatment of this disease.

Clinical utility of whole-genome DNA methylation profiling as a primary molecular diagnostic assay for central nervous system tumors-A prospective study and guidelines for clinical testing.

Background: Central nervous system (CNS) cancer is the 10th leading cause of cancer-associated deaths for adults, but the leading cause in pediatric patients and young adults. The variety and complexity of histologic subtypes can lead to diagnostic errors. DNA methylation is an epigenetic modification that provides a tumor type-specific signature that can be used for diagnosis. Methods: We performed a prospective study using DNA methylation analysis as a primary diagnostic method for 1921 brain tumors. All tumors received a pathology diagnosis and profiling by whole genome DNA methylation, followed by next-generation DNA and RNA sequencing. Results were stratified by concordance between DNA methylation and histopathology, establishing diagnostic utility. Results: Of the 1602 cases with a World Health Organization histologic diagnosis, DNA methylation identified a diagnostic mismatch in 225 cases (14%), 78 cases (5%) did not classify with any class, and in an additional 110 (7%) cases DNA methylation confirmed the diagnosis and provided prognostic information. Of 319 cases carrying 195 different descriptive histologic diagnoses, DNA methylation provided a definitive diagnosis in 273 (86%) cases, separated them into 55 methylation classes, and changed the grading in 58 (18%) cases. Conclusions: DNA methylation analysis is a robust method to diagnose primary CNS tumors, improving diagnostic accuracy, decreasing diagnostic errors and inconclusive diagnoses, and providing prognostic subclassification. This study provides a framework for inclusion of DNA methylation profiling as a primary molecular diagnostic test into professional guidelines for CNS tumors. The benefits include increased diagnostic accuracy, improved patient management, and refinements in clinical trial design.

Permeability of the paranodal junction of myelinated nerve fibers.

We have used fluorescent dextran tracers to test the tightness of the paranodal junction of living or fixed myelinated fibers in mouse sciatic nerve. Both 3 and 70 kDa tracers are able to penetrate from the perinodal space symmetrically into the paranodes on either side of the node of Ranvier at a rate consistent with diffusion through an elongated helical pathway between the paranodal terminal loops of the myelin sheath. This pathway thus provides an access route for movement of water soluble nutrients and metabolites to and from the internodal axon and constitutes a pathway through which juxtaparanodal potassium channels may be activated and may in turn affect nodal excitability. This pathway may also allow access of antibodies and toxic molecules to the internodal axon in paraneoplastic syndromes and demyelinating diseases.

Paranodal permeability in "myelin mutants".

Fluorescent dextran tracers of varying sizes have been used to assess paranodal permeability in myelinated sciatic nerve fibers from control and three "myelin mutant" mice, Caspr-null, cst-null, and shaking. We demonstrate that in all of these the paranode is permeable to small tracers (3 kDa and 10 kDa), which penetrate most fibers, and to larger tracers (40 kDa and 70 kDa), which penetrate far fewer fibers and move shorter distances over longer periods of time. Despite gross diminution in transverse bands (TBs) in the Caspr-null and cst-null mice, the permeability of their paranodal junctions is equivalent to that in controls. Thus, deficiency of TBs in these mutants does not increase the permeability of their paranodal junctions to the dextrans we used, moving from the perinodal space through the paranode to the internodal periaxonal space. In addition, we show that the shaking mice, which have thinner myelin and shorter paranodes, show increased permeability to the same tracers despite the presence of TBs. We conclude that the extent of penetration of these tracers does not depend on the presence or absence of TBs but does depend on the length of the paranode and, in turn, on the length of "pathway 3," the helical extracellular pathway that passes through the paranode parallel to the lateral edge of the myelin sheath.

Novel forms of neurofascin 155 in the central nervous system: alterations in paranodal disruption models and multiple sclerosis.

Stability of the myelin-axon unit is achieved, at least in part, by specialized paranodal junctions comprised of the neuronal heterocomplex of contactin and contactin-associated protein and the myelin protein neurofascin 155. In multiple sclerosis, normal distribution of these proteins is altered, resulting in the loss of the insulating myelin and consequently causing axonal dysfunction. Previously, this laboratory reported that mice lacking the myelin-enriched lipid sulphatide are characterized by a progressive deterioration of the paranodal structure. Here, it is shown that this deterioration is preceded by significant loss of neurofascin 155 clustering at the myelin paranode. Interestingly, prolonged electrophoretic separation revealed the existence of two neurofascin 155 bands, neurofascin 155 high and neurofascin 155 low, which are readily observed following N-linked deglycosylation. Neurofascin 155 high is observed at 7 days of age and reaches peak expression at one month of age, while neurofascin 155 low is first observed at 14 days of age and constantly increases until 5 months of age. Studies using conditional neurofascin knockout mice indicated that neurofascin 155 high and neurofascin 155 low are products of the neurofascin gene and are exclusively expressed by oligodendrocytes within the central nervous system. Neurofascin 155 high is a myelin paranodal protein while the distribution of neurofascin 155 low remains to be determined. While neurofascin 155 high levels are significantly reduced in the sulphatide null mice at 15 days, 30 days and 4 months of age, neurofascin 155 low levels remain unaltered. Although maintained at normal levels, neurofascin 155 low is incapable of preserving paranodal structure, thus indicating that neurofascin 155 high is required for paranodal stability. Additionally, comparisons between neurofascin 155 high and neurofascin 155 low in human samples revealed a significant alteration, specifically in multiple sclerosis plaques.

Incidental Adrenal Mass in a Patient With Surgically Treated Lung Adenocarcinoma.

Adrenal metastases are not uncommon in patients with widespread metastatic lung cancer. Isolated metachronous adrenal metastases in cases of surgically treated lung cancer without long-term evidence of disease are rare and may pose a diagnostic and treatment dilemma. The current literature suggests that in such cases, adrenalectomy provides better median and overall survival rates. This case presents an incidentally discovered isolated adrenal mass in a patient with a past medical history of lung adenocarcinoma that was surgically removed three years before metastasis discovery. The patient successfully underwent adrenalectomy and was disease-free with no apparent complications at her three-month follow-up visit. The case highlights the importance of long-term radiographic surveillance after surgical resection of lung adenocarcinoma for the prompt diagnosis and timely treatment of metachronous metastases.

Widespread choriocarcinoma metastases from de-differentiated gastro-esophageal junction primary adenocarcinoma: A case report with literature review.

BACKGROUND: Non-gestational choriocarcinomas represent a small subset of germ cell tumors. The majority of non-gestational choriocarcinomas arise from the gynecologic tract. In rare cases, they can originate from other sites, and very few such cases have been reported in peer-reviewed literature. We add to this small collection with an interesting case of non-gestational choriocarcinoma arising from a primary gastrointestinal adenocarcinoma. CASE PRESENTATION: A 62-year-old female presented to the emergency department with ocular hemorrhage. Originally thought to have melanoma, full-body computed tomography (CT) revealed widespread metastases including a 3 cm hemorrhagic brain mass, hepatic metastases, and a mass at the gastro-esophageal (GE) junction. Pathology of the intracranial mass revealed a malignant neoplasm consistent with choriocarcinoma. Recent dilation and curettage (D&C) were negative for malignancy. Esophagogastroduodenoscopy (EGD) biopsy of the GE junction mass showed poorly differentiated adenocarcinoma, likely the primary lesion, while the liver biopsy matched the ß-hCG staining pattern as seen in the brain. CONCLUSIONS: Choriocarcinomas can rarely originate outside of the female reproductive tract (non-gestational, primary choriocarcinomas). In the infrequent cases where a gestational origin is clinically unlikely, the differential diagnosis includes a non-gestational primary choriocarcinoma and choriocarcinomatous differentiation in another primary malignancy. Careful correlation with imaging and clinico-pathologic studies is paramount to determining their origin and guiding further clinical treatment.

A Unique Combined Ganglioneuroma Schwannoma Tumor Mimicking Adrenal Malignancy.

A 28-year-old woman with a past medical history significant for cervical cancer was diagnosed with a 2.5 cm adrenal tumor but was lost to follow-up. Two years later, she presented to the emergency room with worsening right upper abdominal and flank pain. The computed tomography (CT) and magnetic resonance imaging (MRI) of the abdomen and pelvis revealed that the right adrenal mass had nearly doubled in size (4.3 cm), was heterogeneous with calcifications, central necrosis and actively uptaking the intravenous (IV) contrast with a delayed washout. The biochemical workup was negative for hyperaldosteronism, hypercortisolism, and pheochromocytoma. She reported an unintentional body weight loss of 40 pounds. Adrenocortical carcinoma or a metastatic malignancy was high on the differential diagnoses list. She underwent a successful laparoscopic adrenalectomy, and final pathology revealed a benign extra-adrenal combined ganglioneurofibroma and schwannoma. These rare benign malignancies alone or in combination may closely mimic the clinical and imaging characteristics of adrenal malignancy and pose a diagnostic and therapeutic dilemma to surgeons as well as cause a significant distress to patients and their families. Thus, it is important to thoroughly document and report these cases in order to increase awareness and improve our understanding of the biology, natural history and management of these extremely rare tumors.

Imaging Manifestations of Creutzfeldt-Jakob Disease and Case Series.

Sporadic Creutzfeldt-Jakob disease (CJD) is the most common prion disease, resulting in rapid neurocognitive decline, and is universally lethal. CJD has a confounding clinical presentation with similarities which overlap with many other neurodegenerative disorders. Brain biopsy is the current gold standard; however, less-invasive initial screening tests are also utilized. These include brain magnetic resonance imaging (MRI), electroencephalography (EEG), and cerebrospinal fluid (CSF) laboratory studies. Five patients presented to our facility with varying levels of nonspecific cognitive impairment and movement disorders. CJD was initially suggested after review of each patient's brain MRI. The T2-weighted fluid attenuation inversion recovery and diffusion-weighted images in each case demonstrated varied classic patterns of signal abnormality involving the cortex, basal ganglia, thalami, and brainstem. EEG and CSF studies were confirmatory in three and four patients, respectively (EEG not performed in one patient). One death occurred two months after initial presentation, and the other four patients were transferred to hospice three, four, nine, and 20 months after initial presentation. Radiological evaluation is an invaluable component of the workup for nonspecific neurodegenerative disorders because brain MRI may suggest the initial diagnosis of CJD, as demonstrated in our presented cases. Familiarity with the spectrum of classic MRI findings suggestive of sporadic CJD can improve radiologists' role in early detection of the most common prion disease. Clinicians may benefit from understanding the utility of the newer CSF laboratory studies (Real-time quaking-induced conversion, T-tau, and 14-3-3 protein), which are far less invasive than the gold standard of brain biopsy. Early diagnosis can help save medical resources and guide clinicians to form appropriate plans of care with the patient and family.

Cardiac arrhythmia and neuroexcitability gene variants in resected brain tissue from patients with sudden unexpected death in epilepsy (SUDEP).

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality in young adults. The exact mechanisms are unknown but death often follows a generalized tonic-clonic seizure. Proposed mechanisms include seizure-related respiratory, cardiac, autonomic, and arousal dysfunction. Genetic drivers underlying SUDEP risk are largely unknown. To identify potential SUDEP risk genes, we compared whole-exome sequences (WES) derived from formalin-fixed paraffin embedded surgical brain specimens of eight epilepsy patients who died from SUDEP with seven living controls matched for age at surgery, sex, year of surgery and lobe of resection. We compared identified variants from both groups filtering known polymorphisms from publicly available data as well as scanned for epilepsy and candidate SUDEP genes. In the SUDEP cohort, we identified mutually exclusive variants in genes involved in µ-opiod signaling, gamma-aminobutyric acid (GABA) and glutamate-mediated synaptic signaling, including ARRB2, ITPR1, GABRR2, SSTR5, GRIK1, CTNAP2, GRM8, GNAI2 and GRIK5. In SUDEP patients we also identified variants in genes associated with cardiac arrhythmia, including KCNMB1, KCNIP1, DPP6, JUP, F2, and TUBA3D, which were not present in living epilepsy controls. Our data shows that genomic analysis of brain tissue resected for seizure control can identify potential genetic biomarkers of SUDEP risk.

Molecular architecture of myelinated nerve fibers: leaky paranodal junctions and paranodal dysmyelination.

Myelinated nerve fibers have evolved to optimize signal propagation. Each myelin segment is attached to the axon by the unique paranodal axoglial junction (PNJ), a highly complex structure that serves to define axonal ion channel domains and to direct nodal action currents through adjacent nodes. Surprisingly, this junction does not entirely seal the paranodal myelin sheath to the axon and thus does not entirely isolate the perinodal space from the internodal periaxonal space. Rather the paranode is penetrated by extracellular pathways between the myelin sheath and the axolemma for movement of molecules and the flow of current to and from the internodal axon. This review summarizes past and current studies demonstrating these pathways and considers what functional roles they subserve. In addition, modern genetic engineering methods permit modification of individual PNJ constituents, which provides an opportunity to define their specific functions. One component in particular, the transverse bands, plays a key role in maintaining the structure and function of the PNJ. Loss of transverse bands results not in frank demyelination but rather in subtle dysmyelination, which causes significant functional impairment. The consequences of such subtle defects in the PNJ are considered along with the relevance of these studies to human diseases of myelin.