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Cureus May 2024Pituitary apoplexy is a result of rapid enlargement of the pituitary, due to episodes of hyperplasia, which outpaces vascular development resulting in ischemia and...
Pituitary apoplexy is a result of rapid enlargement of the pituitary, due to episodes of hyperplasia, which outpaces vascular development resulting in ischemia and potential infarction of pituitary tissue. This can present in several different ways from asymptomatic to hormonal deficiencies. Here we present a case of spontaneous reduction of a non-functioning pituitary mass, likely due to apoplexy, in which the mass went from compromising the optic chiasm to complete reduction and relief of the optic chiasm. The infarction happened spontaneously without treatment and complications. This may encourage future conservative management of pituitary tumors, rather than immediate surgical intervention.
PubMed: 38939255
DOI: 10.7759/cureus.61259 -
Neuro-ophthalmology (Aeolus Press) 2024See-saw nystagmus (SSN) is a rare form of nystagmus characterised by alternating elevation with incyclotorsion of one eye and concomitant depression with excyclotorsion...
See-saw nystagmus (SSN) is a rare form of nystagmus characterised by alternating elevation with incyclotorsion of one eye and concomitant depression with excyclotorsion of the other eye, often due to abnormalities involving the midbrain and parasellar region. Herein, we highlight a rare case of pendular SSN, which demonstrated complete resolution following resection of a pituitary macroadenoma. A patient in their 40s was identified to have SSN and was diagnosed with a pituitary macroadenoma. They underwent an endoscopic endonasal transsellar approach for resection of the pituitary adenoma. Their nystagmus resolved immediately after surgery. From a review of the literature, resolution and/or significant improvement in SSN occurred in 74% of cases following treatment, with 100%, 86% and 50% following treatment for medication-induced, neurological infarcts, and mass-effect aetiologies of SSN, respectively. SSN is a rare entity with a wide array of aetiologies. Identification of the causative aetiology and appropriate treatment can lead to significant improvement or resolution of the nystagmus in most cases.
PubMed: 38933752
DOI: 10.1080/01658107.2023.2299763 -
Journal of Neuro-ophthalmology : the... Jun 2024A 46-year-old man presented with left eye blurring. Automated visual field testing showed an incongruous right hemianopia, with sparing of the lower temporal quadrant in...
A 46-year-old man presented with left eye blurring. Automated visual field testing showed an incongruous right hemianopia, with sparing of the lower temporal quadrant in the right eye. MRI revealed foci of gadolinium enhancement in the optic chiasm and optic tracts. Serologic testing (including myelin oligodendrocyte glycoprotein and neuromyelitis optica antibodies) and cerebrospinal fluid analysis were negative. Whole-body PET/CT scan found no malignancy. Biopsy of the optic chiasm revealed a moderately cellular neoplasm composed of atypical, discohesive cells with enlarged nuclei, prominent eosinophilic nucleoli, and abundant vacuolated cytoplasm. Immunohistochemical stains for CD68 and S100 were positive, whereas those for GFAP, OLIG2, SOX10, and multiple others were negative, supporting a diagnosis of histiocytic neoplasm. Five weeks later, results became available from next-generation sequencing targeting the coding regions of hundreds of malignancy-associated genes and select introns. Alterations associated with histiocytic neoplasms (i.e. BRAF and MAP2K1 mutations) were absent. However, there was a nonsense mutation in the PTEN gene, a hotspot mutation in the TERT gene promotor, and focal amplifications of the CDK4 and MDM2 genes. Additionally, there was chromosome 6q loss, 7 gain, and 10q loss. Based on these findings, the diagnosis was revised to glioblastoma, IDH-wildtype, CNS WHO grade 4. The patient began treatment with temozolomide while continuing radiation therapy. This case illustrates how next-generation sequencing can at times provide more accurate diagnostic information than standard tissue histopathology.
PubMed: 38926909
DOI: 10.1097/WNO.0000000000002207 -
Journal of Neuro-oncology Jun 2024GammaTile® (GT) is a brachytherapy platform that received Federal Drug Administration (FDA) approval as brain tumor therapy in late 2018. Here, we reviewed our...
PURPOSE
GammaTile® (GT) is a brachytherapy platform that received Federal Drug Administration (FDA) approval as brain tumor therapy in late 2018. Here, we reviewed our institutional experience with GT as treatment for recurrent glioblastomas and characterized dosimetric parameter and associated clinical outcome.
METHODS AND MATERIALS
A total of 20 consecutive patients with 21 (n = 21) diagnosis of recurrent glioblastoma underwent resection followed by intraoperative GT implant between 01/2019 and 12/2020. Data on gross tumor volume (GTV), number of GT units implanted, dose coverage for the high-risk clinical target volume (HR-CTV), measured by D or dose received by 90% of the HR-CTV, dose to organs at risk, and six months local control were collected.
RESULTS
The median D to HR-CTV was 56.0 Gy (31.7-98.7 Gy). The brainstem, optic chiasm, ipsilateral optic nerve, and ipsilateral hippocampus median D were 11.2, 5.4, 6.4, and 10.0 Gy, respectively. None of the patients in this study cohort suffered from radiation necrosis or adverse events attributable to the GT. Correlation was found between pre-op GTV, the volume of the resection cavity, and the number of GT units implanted. Of the resection cavities, 7/21 (33%) of the cavity experienced shrinkage, 3/21 (14%) remained stable, and 11/21 (52%) of the cavities expanded on the 3-months post-resection/GT implant MRIs. D to HR-CTV was found to be associated with local recurrence at 6-month post GT implant, suggesting a dose response relationship (p = 0.026). The median local recurrence-free survival was 366.5 days (64-1,098 days), and a trend towards improved local recurrence-free survival was seen in patients with D to HR-CTV ≥ 56 Gy (p = 0.048).
CONCLUSIONS
Our pilot, institutional experience provides clinical outcome, dosimetric considerations, and offer technical guidance in the clinical implementation of GT brachytherapy.
PubMed: 38902561
DOI: 10.1007/s11060-024-04631-4 -
Child's Nervous System : ChNS :... Jun 2024Pediatric low-grade gliomas (pLGGs) are the most common brain tumor types affecting children. Although gross-total resection remains the treatment of choice, many tumors...
Pediatric low-grade gliomas (pLGGs) are the most common brain tumor types affecting children. Although gross-total resection remains the treatment of choice, many tumors are not amenable to complete removal, because they either involve midline structures, such as the optic chiasm or hypothalamus, and are not conducive to aggressive resection, or have diffuse biological features and blend with the surrounding brain. Historically, radiation therapy was used as the second-line option for disease control, but with the recognition that this often led to adverse long-term sequelae, particularly in young children, conventional chemotherapy assumed a greater role in initial therapy for unresectable tumors. A variety of agents demonstrated activity, but long-term disease control was suboptimal, with more than 50% of tumors exhibiting disease progression within 5 years. More recently, it has been recognized that a high percentage of these tumors in children exhibit constitutive activation of the mitogen-activated protein kinase (MAPK) pathway because of BRAF translocations or mutations, NFI mutations, or a host of other anomalies that converged on MAPK. This led to phase 1, 2, and 3 trials that explored the activity of blocking this signaling pathway, and the efficacy of this approach compared to conventional chemotherapy. Despite initial promise of these strategies, not all children tolerate this therapy, and many tumors resume growth once MAPK inhibition is stopped, raising concern that long-term and potentially life-long treatment will be required to maintain tumor control, even among responders. This observation has led to interest in other treatments, such as immunotherapy, that may delay or avoid the need for additional treatments. This chapter will summarize the place of immunotherapy in the current armamentarium for these tumors and discuss prior results and future options to improve disease control, with a focus on our prior efforts and experience in this field.
PubMed: 38884777
DOI: 10.1007/s00381-024-06491-9 -
Clinical Oncology (Royal College of... May 2024This study aimed to demonstrate the feasibility and evaluate the dosimetric effect and clinical impact of dose-painting proton radiotherapy (PRT) guided by functional...
AIMS
This study aimed to demonstrate the feasibility and evaluate the dosimetric effect and clinical impact of dose-painting proton radiotherapy (PRT) guided by functional MRI in non-enhancing high-grade gliomas (NE-HGGs).
MATERIALS AND METHODS
The 3D-ASL and T2 FLAIR MR images of ten patients with NE-HGGs before radiotherapy were studied retrospectively. The hyperintensity on T2 FLAIR was used to generate the planning target volume (PTV), and the high-perfusion volume on 3D-ASL (PTV-ASL) was used to generate the simultaneous integrated boost (SIB) volume. Each patient received pencil beam scanning PRT and photon intensity-modulated radiotherapy (IMRT). There were five plans in each modality: (1) Uniform plans (IMRT60 vs. PRT60): 60Gy in 30 fractions to the PTV. (2)-(5) SIB plans (IMRT72, 84, 96, 108 vs. PRT72, 84, 96, 108): Uniform plan plus additional dose boost to PTV-ASL in 30 fractions to 72, 84, 96, 108 Gy. The dosimetric differences between various plans were compared. The clinical effects of target volume and organs at risk (OARs) were assessed using biological models for both tumor control probability (TCP) and normal tissue complication probability (NTCP).
RESULTS
Compared with the IMRT plan, the D2 and D50 of the PRT plans with the same prescription dose increased by 1.27-4.12% and 0.64-2.01%, respectively; the R30 decreased by > 32%; the dose of brainstem and chiasma decreased by > 27% and >32%; and the dose of normal brain tissue (Br-PTV), optic nerves, eyeballs, lens, cochlea, spinal cord, and hippocampus decreased by > 50% (P < 0.05). The maximum necessary dose was 96GyE to achieve >98% TCP for PRT, and it was 84Gy to achieve >91% TCP for IMRT. The average NTCP of Br-PTV was 1.30% and 1.90% for PRT and IMRT at the maximum dose escalation, respectively. The NTCP values of the remaining OARs approached zero in all PRT plans.
CONCLUSION
The functional MRI-guided dose escalation using PRT is feasible while sparing the OARs constraints and demonstrates a potential clinical benefit by improving TCP with no or minimal increase in NCTP for tissues outside the PTV. This retrospective study suggested that the use of PRT-based SIB guided by functional MRI may represent a strategy to provide benefits for patients with NE-HGGs.
PubMed: 38876805
DOI: 10.1016/j.clon.2024.05.011 -
World Neurosurgery Jun 2024Cerebrospinal fluid (CSF) leak during endoscopic endonasal transsphenoidal surgery (EETS) can lead to postoperative complications. The clinical and anatomic risk factors...
INTRODUCTION
Cerebrospinal fluid (CSF) leak during endoscopic endonasal transsphenoidal surgery (EETS) can lead to postoperative complications. The clinical and anatomic risk factors of intraoperative CSF leak are not well defined. We applied a 2D convolutional neural network (CNN) machine learning (ML) model to identify risk factors from preoperative magnetic resonance imaging (MRI).
METHODS
All adults who underwent EETS at our institution from January 2007 to March 2023 who had accessible preoperative stereotactic MRIs were included. A retrospective classic statistical analysis was performed to identify demographic, clinical, and anatomic risk factors of intraoperative CSF leak. Stereotactic T2 brain MRIs were utilized to train and test a 2D CNN model.
RESULTS
220 patients were included, 81 (36.8%) of whom experienced intraoperative CSF leak. Amongst all preoperative variables, visual disturbance was the only statistically significant identified risk factor (p-value:0.008). The trained 2D CNN model predicted CSF leak with 92% accuracy and area under receiver operative characteristic curve of 0.90 (sensitivity of 86% and specificity of 93%). Class activation mapping (CAM) of this model revealed that anatomic regions of CSF flow were most important in predicting CSF leak.
CONCLUSION
Further review of the CAM gradients revealed regions of the diaphragma sellae, clinoids, temporal horns, and the optic nerves to have anatomical correlation to the risks of intraoperative CSF leak. Additonally, visual disturbances from anatomic compression of the optic chiasm was the only identified clinical risk factor. We believe that our 2D CNN model can help improve a treating team's anticipation of and preparation for an intraoperative leak.
PubMed: 38876190
DOI: 10.1016/j.wneu.2024.06.043 -
BioRxiv : the Preprint Server For... May 2024Albinism is an inherited disorder characterized by disrupted melanin production in the eye, and often in the skin and hair. This retinal hypopigmentation is accompanied...
Albinism is an inherited disorder characterized by disrupted melanin production in the eye, and often in the skin and hair. This retinal hypopigmentation is accompanied by pathological decussation of many temporal retinal afferents at the optic chiasm during development, ultimately resulting in partially superimposed representations of opposite visual hemifields in each cortical hemisphere. Within these aberrant regions of hemifield overlap, individual voxels have been shown to have bilateral, dual population receptive fields (pRFs) responding to roughly mirror-image locations across the vertical meridian. Nonetheless, how these two conflicting inputs combine to determine a voxel's response to image contrast is still unknown. To address this, we stimulated the right and left hemifields with separately controlled sinusoidal gratings, each having a variety of contrasts (0, 8, 20, 45, 100%), and extracted voxel-wise BOLD response amplitudes to each contrast combination in visual areas V1-V3. We then compared voxels' responses to each hemifield stimulated individually with conditions when both hemifields were stimulated simultaneously. We hypothesized that simultaneous stimulation of the two pRF components will result in either a suppressive or facilitative interaction. However, we found that BOLD responses to simultaneous stimulation appeared to reflect simple summation of the neural activity from the individual hemifield conditions. This suggests that the superimposed opposite hemifield representations do not interact. Thus, dual pRFs in albinism likely reflect two co-localized, but functionally independent populations of neurons each of which respond to a single hemifield. This finding is commensurate with psychophysical studies which have shown no clear perceptual interaction between opposite visual hemifields in human albinism.
PubMed: 38853944
DOI: 10.1101/2024.05.26.595603 -
Eye (London, England) Jun 2024A recent anatomical study of the human optic chiasm cast doubt on the widespread assumption that nerve fibres travelling in the human optic nerve and chiasm are arranged... (Review)
Review
A recent anatomical study of the human optic chiasm cast doubt on the widespread assumption that nerve fibres travelling in the human optic nerve and chiasm are arranged retinotopically. Accordingly, a scoping literature review was performed to determine what is known about the nerve fibre arrangement in these structures. Meta-analysis suggested that the average number of fibres in each optic nerve was 1.023 million with an inter-individual range of approximately 50% of the mean. Loss of nerve fibres with age (approximately 3,400 fibres/year) could not account for this variability. The review suggested that there might be a retinotopic arrangement of nerve fibres in the orbital portion of the optic nerve but that this arrangement is most likely to be lost posteriorly with a more random distribution of nerve fibres at the chiasm. Limited studies have looked at nerve fibre arrangement in the chiasm. In summary, the chiasm is more 'H-shaped' than 'X-shaped': nerve fibre crossings occur paracentrally with nerves in the centre of the chiasm travelling coronally and in parallel. There is interaction between crossed and uncrossed fibres which are widely distributed. The review supports the non-existence of Wilbrand's knee. Considerable further work is required to provide more precise anatomical information, but this review suggests that the assumed preservation of retinotopy in the human optic nerve and chiasm is probably not correct.
PubMed: 38849598
DOI: 10.1038/s41433-024-03137-7 -
Operative Neurosurgery (Hagerstown, Md.) Jun 2024The endoscopic endonasal approach for resection of craniopharyngiomas has gained popularity because of its minimal need for retraction and superior visualization of and...
Use of Real-Time Superior Hypophyseal Artery Indocyanine Green Angiogram During Endoscopic Resection of a Third Ventricular Craniopharyngioma: 2-Dimensional Operative Video.
The endoscopic endonasal approach for resection of craniopharyngiomas has gained popularity because of its minimal need for retraction and superior visualization of and access to the optic chiasm.1-4 Despite these advantages, the proximity of craniopharyngiomas to the optic apparatus still challenges the preservation of visual function.5-10 Indocyanine green (ICG) angiography can evaluate the perfusion of the chiasm and can predict visual outcomes after endonasal approaches, in addition to known uses of the dye.3 ICG angiography may therefore hold promise in the real-time assessment of optic chiasm perfusion during resection of craniopharyngiomas by delineating details of the superior hypophyseal artery (SHA) system. Here, we present a case in which ICG angiogram was used to assess the perfusion of the chiasm before, during, and after tumor resection. This technique signaled thrombosis of the left principal SHA during tumor resection that was compensated by the anastomotic SHA system from the right. The case shows an endoscopic endonasal approach for the resection of a third ventricular craniopharyngioma in a 21-year-old woman presenting with unremitting headaches, endocrine dysfunction, and vision loss. Postoperatively, the patient's neurological examination remained unchanged and visual function improved within 2 weeks. This case underscores the potential for real-time intraoperative ICG angiography to assist in the careful resection of craniopharyngiomas while improving visual outcomes. Institutional review board approval was not required; the patient consented to the procedure and to publishing of the operative video.
PubMed: 38847508
DOI: 10.1227/ons.0000000000001225