Primary glioblastoma multiform (GBM) of the optic nerve and chiasma: A case report and systematic review of the literature.

Key Clinical Message: Primary GBM of the optic nerve and chiasma should be included in the differential diagnosis of progressive lesions despite initial treatment; clinicians should avoid delay in confirming the histology to initiate proper treatment and improve prognosis. Abstract: Primary GBM of the optic nerve or chiasma is very rare. The characteristics of this condition have not been well-described, which poses difficulties in establishing the correct diagnosis, affecting the treatment and the prognosis. We present a case of GBM of the optic chiasma diagnosed through an open biopsy at our centre. Following the PRISMA statement, we also conducted a systematic review after protocol registration in PROSPERO (CRD42021285855). We searched Medline and Embase through Ovid from inception until December 31, 2021. Two reviewers independently screened the studies. Studies were eligible for inclusion if they reported cases of primary GBM confined to the optic nerve or chiasma as the initial radiological diagnosis. A 77-year-old female was referred for progressive visual loss lasting 8 weeks. MRI revealed a suspected lesion in the left chiasma. The patient's vision deteriorated further despite initially diagnosing an inflammatory process and empirical treatment with corticosteroids. Subsequently, the patient underwent an open biopsy and surgical debulking. Histology, including epigenetic analysis, confirmed GBM grade IV. Radiochemotherapy was administered. The patient died 19 months after surgery. We identified 45 similar cases (22 female) reported in 35 studies between 1949 and 2020. The mean age of the cases was 61 (SD = 14.6). Most cases were misdiagnosed and mistreated accordingly, so there was a median delay of 8 weeks (IQR: 5-14 weeks) in obtaining histological confirmation of the diagnosis, delaying the initiation of appropriate treatment. Five cases became no treatment since the patients died shortly after the delayed histologic diagnosis. The Kaplan-Meier estimate indicated that most patients died within 20 months of presentation, with a 1-year survival rate of 50%, and untreated cases had very low survival rates compared to treated cases. Primary GBM of the optic nerve and chiasma is a rare condition primarily affecting adults. The rarity of this condition contributes to initial misdiagnosis, mistreatment, and delays in confirming the histology and initiating appropriate treatment. The prognosis remains poor, but treatment, including surgery and radiochemotherapy, improves survival.

Synthetically induced Arabidopsis thaliana autotetraploids provide insights into the analysis of meiotic mutants with altered crossover frequency.

Mutations affecting crossover (CO) frequency and distribution lead to the presence of univalents during meiosis, giving rise to aneuploid gametes and sterility. These mutations may have a different effect after chromosome doubling. The combination of altered ploidy and mutations could be potentially useful to gain new insights into the mechanisms and regulation of meiotic recombination; however, studies using autopolyploid meiotic mutants are scarce. Here, we have analyzed the cytogenetic consequences in colchicine-induced autotetraploids (colchiploids) from different Arabidopsis mutants with an altered CO frequency. We have found that there are three types of mutants: mutants in which chiasma frequency is doubled after chromosome duplication (zip4, mus81), as in the control; mutants in which polyploidy leads to a higher-than-expected increase in chiasma frequency (asy1, mer3, hei10, and mlh3); and mutants in which the rise in chiasma frequency produced by the presence of two extrachromosomal sets is less than doubled (msh5, fancm). In addition, the proportion of class I/class II COs varies after chromosome duplication in the control. The results obtained reveal the potential of colchiploid meiotic mutants for better understanding of the function of key proteins during plant meiosis. This is especially relevant considering that most crops are polyploids.

MRI-Based Evaluation of the Flexor Digitorum Superficialis Anatomy: Investigating the Prevalence and Morphometry of the "Chiasma Antebrachii".

Recent dissection studies resulted in the introduction of the term "chiasma antebrachii", which represents an intersection of the flexor digitorum superficialis (FDS) tendons for digits 2 and 3 in the distal third of the forearm. This retrospective investigation aimed to provide an MRI-based morphologic analysis of the chiasma antebrachii. In 89 patients (41 women, 39.3 ± 21.3 years), MRI examinations of the forearm (2010-2021) were reviewed by two radiologists, who evaluated all studies for the presence and length of the chiasma as well as its distance from the distal radioulnar and elbow joint. The chiasma antebrachii was identified in the distal third of the forearm in 88 patients (98.9%), while one intersection was located more proximally in the middle part. The chiasma had a median length of 28 mm (interquartile range: 24-35 mm). Its distances to the distal radioulnar and elbow joint were 16 mm (8-25 mm) and 215 mm (187-227 mm), respectively. T1-weighted post-contrast sequences were found to be superior to T2- or proton-density-weighted sequences in 71 cases (79.8%). To conclude, the chiasma antebrachii is part of the standard FDS anatomy. Knowledge of its morphology is important, e.g., in targeted injections of therapeutics or reconstructive surgery.

ASYNAPSIS 1 ensures crossover fidelity in polyploid wheat by promoting homologous recombination and suppressing non-homologous recombination.

During meiosis, the chromosome axes and synaptonemal complex mediate chromosome pairing and homologous recombination to maintain genomic stability and accurate chromosome segregation. In plants, ASYNAPSIS 1 (ASY1) is a key component of the chromosome axis that promotes inter-homolog recombination, synapsis and crossover formation. Here, the function of ASY1 has been cytologically characterized in a series of hypomorphic wheat mutants. In tetraploid wheat, asy1 hypomorphic mutants experience a reduction in chiasmata (crossovers) in a dosage-specific manner, resulting in failure to maintain crossover (CO) assurance. In mutants with only one functional copy of ASY1, distal chiasmata are maintained at the expense of proximal and interstitial chiasmata, indicating that ASY1 is required to promote chiasma formation away from the chromosome ends. Meiotic prophase I progression is delayed in asy1 hypomorphic mutants and is arrested in asy1 null mutants. In both tetraploid and hexaploid wheat, single asy1 mutants exhibit a high degree of ectopic recombination between multiple chromosomes at metaphase I. To explore the nature of the ectopic recombination, Triticum turgidum asy1b-2 was crossed with wheat-wild relative Aegilops variabilis. Homoeologous chiasmata increased 3.75-fold in Ttasy1b-2/Ae. variabilis compared to wild type/Ae. variabilis, indicating that ASY1 suppresses chiasma formation between divergent, but related chromosomes. These data suggest that ASY1 promotes recombination along the chromosome arms of homologous chromosomes whilst suppressing recombination between non-homologous chromosomes. Therefore, asy1 mutants could be utilized to increase recombination between wheat wild relatives and elite varieties for expediting introgression of important agronomic traits.

Cytogenetic Analysis of the Bimodal Karyotype of the Common European Adder, Vipera berus (Viperidae).

Vipera berus is the species with the largest range of snakes on Earth and one of the largest among reptiles in general. It is also the only snake species found in the Arctic Circle. Vipera berus is the most involved species of the genus Vipera in the process of interspecific hybridization in nature. The taxonomy of the genus Vipera is based on molecular markers and morphology and requires clarification using SC-karyotyping. This work is a detailed comparative study of the somatic and meiotic karyotypes of V. berus, with special attention to DNA and protein markers associated with synaptonemal complexes. The karyotype of V. berus is a remarkable example of a bimodal karyotype containing both 16 large macrochromosomes and 20 microchromosomes. We traced the stages of the asynchronous assembly of both types of bivalents. The number of crossing-over sites per pachytene nucleus, the localization of the nucleolar organizer, and the unique heterochromatin block on the autosomal bivalent 6-an important marker-were determined. Our results show that the average number of crossing-over sites per pachytene nucleus is 49.5, and the number of MLH1 sites per bivalent 1 reached 11, which is comparable to several species of agamas.

A Case of Suprasellar, Intrasellar, and Infrasellar Meningioma Presenting as a Visual Field Defect in an Obese Female.

Bitemporal hemianopia is the most common visual field defect encountered in suprasellar meningiomas compressing the optic chiasma and its vascular supply. It is hard to distinguish between meningioma and tumors that arise from suprasellar, intrasellar, and infrasellar extensions. Clinical findings, hormonal levels, and radiological findings could help in labeling it as meningioma. A 53-year-old obese woman with a history of blurred vision more in the right eye, loss of smell, and a headache was diagnosed with meningioma having suprasellar, intrasellar, and infrasellar extension on neuroimaging. She developed bitemporal hemianopia, which gradually worsened over the course of six months with concomitant headaches and dizziness that was treated with analgesics leading to a delayed diagnosis. As she was symptomatic, it was decided to resect her tumor. The patient underwent an endoscopic transsphenoidal approach for tumor resection. Successful excision of the tumor was accomplished. Postoperatively on further evaluation, the patient's anosmia and the visual deficit were resolved. This instance shows that meningioma located in the sella can cause symptoms like anosmia and visual field loss, which should not be neglected. It also underlines the significance of visual field evaluation on a regular basis as this might predict radiological and symptomatic progression.

Comparative Evaluation of Two SD-OCT Macular Parameters (GCC, GCL) and RNFL in Chiasmal Compression.

Purpose: To evaluate the relationship between different macular thickness parameters analyzed by SD-OCT and the central visual field (VF) evaluated with automated kinetic perimetry in a cohort of patients with pituitary tumors. Methods: Data from patients with pituitary adenoma treated at Reims University Hospital between October 1st, 2017, and May 31st, 2018 were collected. All patients underwent an automated kinetic perimetry and a SD-OCT to map the ganglion cell complex (GCC), the ganglion cell layer (GCL) thickness and the retinal nerve fiber layer (RNFL) using devices from two different manufacturers. Univariate and multivariate analysis were used to evaluate the correlation between the area of central VF in square degrees (deg2) and the SD-OCT parameters (µm). Results: Eighty-eight eyes were included in the analysis. All the thickness parameters measured in SD-OCT decreased with the visual field alteration. The best correlation was observed between superior thickness parameters (GCC, GCL) and the inferior central visual field. The most pertinent predictive factors for visual field loss were the inferior central GCL and the nasal RNFL (both AUC=0.775) with a sensitivity respectively of 86% and 70%. Conclusion: This study suggests that both GCC, GCL thickness parameters could be reliable predictors of central visual field impairment in patients with pituitary tumors. There was no significative difference between both devices.

Evaluation of optic nerve diameters in individuals with neurofibromatosis and comparison of normative values in different pediatric age groups.

AIM: Our study aimed to report the normative values for optic nerve diameter in different age groups in MR imaging (MRI) in the pediatric population and to find a cut-off value for diagnosis in different age groups to be used for the diagnosis of optic glioma in patients with Neurofibromatosis 1(NF1). MATERIALS-METHODS: Orbital MRI obtained from 2011 to 2021 for children with and without NF1 were reviewed. Patients were divided into three groups: NF1 with glioma (group 1, n = 38), NF1 without glioma (group 2, n = 57), and healthy controls (group 3, n = 295). Two radiologists assessed diameter and tortuosity using validated criteria. The optic nerve measurements were obtained by two radiologists in two plans (axial and coronal sections) at five locations; retroocular, midsegment, and prechiasmatic segment on axial plane and retroocular segment and chiasmatic on coronal plane. RESULTS: Optic nerves were divided into 4 age groups: 0-2 years, 2-6 years, 6-12 years, and 12-18 years. It was observed that optic nerve diameters increased with age in healthy individuals. In subjects in groups 1 and 2, the mean diameter of the optic nerve was significantly greater at all locations compared with control individuals. Tortuosity scores were significantly associated in NF1 subjects with optic glioma than in NF1 subjects without optic glioma. CONCLUSION: We present the normative values obtained by measuring optic nerve diameters in pediatric populations (0-18 years) on MRI of our center. A rapid increase in optic nerve diameter was observed in the first 6 years of life, followed by a slower increase. Quantitative reference values for optic nerve diameter will benefit the development of objective diagnostic criteria for optic nerve gliomas (ONGs) secondary to NF1.

Awake Microsurgical Resection for Optochiasmatic Cavernous Malformation.

Cavernous malformations (CM) affect approximately 0.5% of the population, with only a limited portion being located in the optic nerve and chiasma. The clinical presentation is determined by their locations. In the optochiasmatic CM, the acute visual disturbance is the most common presentation. Chronically, many show a progressive visual loss, chronic headache, and pituitary disturbances. The differential diagnosis includes optic glioma, arteriovenous malformations, aneurysm, craniopharyngioma, pituitary apoplexy, and inflammatory conditions. In Video 1, we present the case of a 39-year-old woman with a history of a hemorrhagic optochiasmatic cavernoma in 2016, who started using propranolol to reduce the lesion and symptoms of visual loss. Moreover, the first microsurgical resection of the cavernoma and evacuation of the hematoma were performed in the same year. Owing to evolvement from a partial to a total vision loss in the left eye and presentation of new symptoms in the right eye, the patient underwent microsurgical resection. The surgery was performed sequentially. An awake craniotomy was performed to monitor the chiasma and right optic nerve. The postoperative magnetic resonance imaging showed complete resection of the CM, and the patient fully recovered. The patient signed the institutional consent form, stating that he or she accepts the procedure and allows the use of his or her images and videos for any type of medical publications in conferences and/or scientific articles.

Ultrasonographic test for detecting the chiasma plantare formation between the flexor hallucis longus and flexor digitorum longus.

PURPOSE: Flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendons are frequently used in surgery. Therefore, it is necessary to evaluate the chiasma plantare formation preoperatively. The development of ultrasonography (US) may help the chiasma plantare formation evaluation. The purpose of this study is to prove the usefulness of the US method using cadavers. METHODS: Eleven cases (twenty-two ankles) were obtained from Asian adult cadavers. At first, we evaluated and compared the chiasma plantare formation using US. Later, we evaluated that using the findings after dissection as type A (connection from FHL to FDL of the second toe), type B (connection from FHL to the second and third toes), type C (connection from FHL to the second through fourth toes), or type D (connection from FHL to all lesser toes). RESULTS: Chiasma plantare formation was classified as types A and B in fifteen and seven ankles, respectively. After dissection, chiasma plantare formation was classified as types A, B, and C in fourteen, six, and two ankles, respectively. Therefore, there was an 86% similarity between the two methods. CONCLUSIONS: Chiasma plantare formation can be reliably and noninvasively evaluated using US. This may be useful for preoperative rehabilitation or surgical procedure planning.

Cytological Monitoring of Meiotic Crossovers in Spermatocytes and Oocytes.

Crossing-over between homologous chromosomes is essential for accurate chromosome segregation at anaphase-I of meiosis. Defective crossing-over is associated with infertility, pregnancy miscarriage, and congenital disease. This chapter presents optimized protocols for the analysis of meiotic crossovers at the cytological level in spermatocytes and oocytes from mouse. The first approach employs immunocytology to detect MLH1, a DNA mismatch-repair protein that specifically marks crossover sites in the pachytene stage of meiotic prophase-I. These immunocytological methods have general utility for the analysis of other recombination steps, such as initiation and DNA strand exchange. The second approach visualizes chiasmata, the points of physical exchange between homologous chromosomes that are present during the diakinesis and metaphase-I stages. Both approaches are readily adaptable to the analysis of crossing over in other vertebrate species.

[Chiasmatic syndrome]. / Syndrome chiasmatique.

The optic chiasm is an essential anatomical structure in neuro-ophthalmology. The systematization of the visual pathways results from the arrangement of the retinal ganglion cell fibers. It explains the signs of chiasmal syndrome. A good knowledge of the anatomy permits to correlate visual field defects with imaging results. It is now possible to map the organization of the ganglion cell fibers within the chiasm. Their hemidecussation allows for stereoscopic vision in humans. The causes of chiasmal syndrome are multiple, but tumors and compressive causes predominate. The proximity of the pituitary region to the chiasm accounts for the frequency of chiasmal syndrome, which involves ophthalmologists not only through dysfunction of the visual pathway, which may be the presenting sign, but also through possible complications throughout the course of the disease. This review aims to synthesize the embryology, anatomy and principles of work-up for chiasmal syndrome as well as its many possible causes.

How to Perform an Accurate Analysis of Metaphase I Chromosome Configurations in Autopolyploids of Arabidopsis thaliana.

During meiosis, accurate segregation of chromosomes requires the formation of bivalents at metaphase I. In autopolyploids, there are more than two copies of each chromosome with the same chance to form chiasmata at meiosis. This leads to the formation of multivalent configurations in which chiasma quantification is rather complicated. Here, we present an improved cytological protocol, including fluorescence in situ hybridization, to obtain high quality spreads of metaphase I chromosomes from Arabidopsis thaliana autotetraploids. This method allows an accurate analysis of the different meiotic configurations and enables the assessment of the number of chiasmata formed by each tetrasome (group of four homologs).

Anatomical Study of the Compositions and Internal Connections of the Chiasma Plantare (Master Knot of Henry): Exploring Its Possible Clinical Impact.

The purposes of this study were to integrate the types of interconnecting fibers among components of the chiasma plantare and to deduce their flexion actions. The chiasma plantare and the long flexor tendons in 52 cadaveric feet (26 left feet and 25 right feet) were dissected and removed via gross anatomic dissection. The connections among the flexor digitorum longus (FDL), flexor hallucis longus (FHL), and quadratus plantae (QP) were then classified and analyzed. The connection between the FHL and FDL was type I in 43 (86%) cases, type III in 2 (4%) cases, and type V in 5 (10%) cases, with the FHL manipulating the first through third toes and the FDL manipulating the first through the fifth toes. The shape of the QP in 28 (56%) cases exhibited a 2-headed QP, and in 22 (44%) cases, a medial-headed QP. The composition of the chiasma plantare was 2 layers in 28 (56%) cases and 3 layers in 22 (44%) cases: 9 (18%) cases were type a, 2 (4%) cases were type b1, and 1 (2%) case each was classified as type b2 and b3. The FHL controlled the second toe in 10 (20%) cases; both the second and third toes in 27 (54%) cases; and the second, third, and fourth toes in 13 (26%) cases. The QP manipulated the third and fourth toes in all cases, the second toe in 38 (76%) cases, and the fifth toe in 11 (22%) cases. These data suggest that such variations might result from tendon transfer. In conclusion, we considered the FDL to be more advanced for the recovery of both the ankle and the forefoot based on this study.

Modern neuro-ophthalmological evaluation of patients with pituitary disorders.

Pituitary adenomas can manifest as ophthalmological symptoms, such as decreased vision, impaired visual field or diplopia. It is important to recognize these neuro-ophthalmological syndromes to achieve early diagnosis and treatment and to improve prognosis. Currently, ophthalmological examination includes precise measuring instruments, such as optical coherence tomography (OCT), which allows the evaluation of optic atrophy related to compression of the anterior optic tract. These measurements are reproducible and are useful for diagnostic and prognostic evaluation. In this review, we describe the ophthalmological syndromes associated with pituitary tumours: anterior optic pathway compression, followed by oculomotor disorders and pituitary apoplexy.

Increased frequency of cataract surgery in patients over age 50 with pituitary macroadenomas and chiasmal compression.

BACKGROUND: Patients with visual loss from macroadenomas compressing their optic apparatus may also have concomitant age-related visual pathology such as cataracts. How these two pathologies interact with each other is not well documented. OBJECTIVE: The interaction between these two pathologies in elderly patients is the subject of this study. METHODS: We identified a series of non-functioning macroadenoma patients over age 50 years with tumors compressing the chiasm who underwent transsphenoidal surgery at our institution between 2004 and 2018. Pre- and post-operative visual complaints, tumor size and extent of resection were analyzed. Prevalence of the diagnosis of cataract and prevalence of cataract surgery in each decade were compared with national averages. RESULTS: We identified 200 patients who met selection criteria. 18% of these patients had a diagnosis of cataract and 12.5% had cataract surgery. Compared with the Eye Diseases Prevalence Research Group (EDPRG) study, the prevalence of cataract surgery was 2.5 times the national average of 5.1%. 32% of these patients had no improvement in their vision after cataract surgery but 76% improved after transsphenoidal surgery. CONCLUSIONS: We reported a high prevalence of cataract surgery in patients over age 50 in patients with pituitary macroadenomas compressing the optic pathway compared with national averages in patients without adenomas. While visual loss from adenoma likely precipitated more cataract surgeries in this group of patients, some who may not have required it, those patients with cataracts who did not have their cataracts extracted were less likely to recover vision after transsphenoidal surgery. Addressing both pathologies is beneficial.

Resolution of symptomatic secondary empty sella syndrome following lumbar-peritoneal shunt.

BACKGROUND: Post-surgical empty sella is related to the removal of pituitary tumors either from the transcranial or transphenoidal route, rendering diaphragma sellae incompetent at the end of the procedure. This subsequently leads to herniation of the third ventricle and optic apparatus into the empty sella. Studies have shown that in 50% of the cases, individuals with primary and secondary empty sella syndrome have developed defects in the visual fields. Benign increased intracranial pressure, cerebrospinal rhinorrhea, papilledema, and abnormalities affecting visual acuity may also occur as a result of empty sella. CASE DESCRIPTION: This case report discusses a rare treatment option for the symptomatic secondary empty sella syndrome. Patient underwent lumbar drain placement and that resulted in astonishingly significant improvement in vision. Keeping in view the beneficial effect of lumbar drain, lumbar-peritoneal (LP) shunt was inserted which showed drastic improvement in vision. CONCLUSION: The surgical outcome of symptomatic cases of ESS is favorable. Various common surgical options were reported in literature; however, we have discussed an unconventional surgical option with an impressive outcome.

Competition for Chiasma Formation Between Identical and Homologous (But Not Identical) Chromosomes in Synthetic Autotetraploids of Arabidopsis thaliana.

Polyploid organisms provide additional opportunities to study meiosis in a more complex context since more than two potential homologous chromosomes are available. When the chromosome complement of a diploid individual is duplicated, each chromosome is accompanied by one identical and two homologous chromosomes within the same nucleus. In this situation, a competition in pairing/synapsis/chiasma formation between identical and homologous (but not necessarily identical) chromosomes can occur. Several studies have been conducted in different species to address whether there are preferences in crossover formation between identical rather than homologous chromosomes. In this study, multivalent and chiasma frequencies were cytologically analyzed in synthetic autotetraploids of Arabidopsis thaliana including the accessions Col, Ler, and the Col/Ler hybrid. Fluorescence in situ hybridization was conducted to identify each chromosome at metaphase I. The new Col and Ler tetraploids showed high multivalent frequencies, exceeding the theoretical 66.66% expected on a simple random end-pairing model, thus indicating that there are more than two autonomous synaptic sites per chromosome despite their small size. However, a significant excess of bivalent pairs was found in the Col/Ler hybrid, mainly due to the contribution of chromosomes 2 and 3. The mean chiasma frequencies of the three artificial autotetraploids were about twofold the corresponding mean cell chiasma frequencies of their diploid counterparts. The relative contribution of each chromosome to the total chiasma frequency was similar in the three genotypes, with the exception of a lower contribution of chromosome 3 in the hybrid. Preferences for chiasma formation between identical and homologous chromosomes were analyzed in Col/Ler 4x, taking advantage of the cytological differences between the accessions: variations in the size of the 45S rDNA region on the short arm of chromosome 2 and changes in the size and localization of the 5S rDNA region in chromosome 3. We observed a different behavior of chromosomes 2 and 3, i.e., random chiasma formation between identical and homologous chromosomes 2, and preferences for chiasma formation between homologous chromosomes 3. Hence, our results reveal the existence of chromosome-specific mechanisms responsible for these preferences.

[A case report of chordoid glioma with unusual features: Immunohistochemical and molecular findings and differential diagnoses]. / Un cas de gliome chordoïde inhabituel : aspects immunohistochimiques et moléculaires et diagnostics différentiels.

We report the case of a 63-year-old healthy patient who was admitted for surgery of a suprasellar tumor with extension to the optic chiasm responsible of visual disturbance. Histopathological examination revealed a tumoral proliferation composed of epithelioid cells without atypia arranged in cords in a mucinous matrix surrounded by some lymphocytic inflammatory infiltrates. On immunohistochemistry, the neoplastic cells strongly expressed GFAP and CD34, a weak expression of EMA, an expression of TTF1 without immunoreactivity for brachyury. Ki-67 labeling index was low around 1%. The diagnosis of chordoid glioma was made. Surprisingly, tumor cells expressed IDH1R132H but molecular analysis did not reveal any mutation of IDH1/2 genes. There was no expression of p53 but high overexpression of EGFR. Chordoid glioma is a rare and low-grade entity. The precise histogenesis remains debated. Our case is unusual because of the infiltration of the optic chiasm and because of the immunoexpression of IDH1R132H without underlying mutations of IDH1/2 genes.