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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 -
Frontiers in Surgery 2024Hemangiopericytoma (HPC) constitutes less than 1% of all primary central nervous system tumors. It is a vascular neoplasm with potential malignancy that, in rare...
UNLABELLED
Hemangiopericytoma (HPC) constitutes less than 1% of all primary central nervous system tumors. It is a vascular neoplasm with potential malignancy that, in rare instances, manifests as a primary lesion within the brain. Typically, it originates from the meninges. Here, we describe an exceptionally uncommon sellar region solitary fibrous tumor/hemangiopericytoma (SFT/HPC) that mimicked a nonfunctional pituitary adenoma.
CASE PRESENTATION
A 54-year-old male was referred to our hospital due to progressive blurred vision in the left eye over the past year. A homogeneous iso-dense extra-axial intrasellar round mass with extension into the suprasellar region, mainly on the left side, along with bony erosion and osteolysis around the sellar region, was observed on a brain computed tomography (CT) scan. Brain magnetic resonance imaging (MRI) revealed a well-defined 251,713 mm mass with iso-signal on T1-weighted images and hypersignal on T2-weighted images, originating from the pituitary gland within the sella turcica. The mass avidly enhanced following Gadolinium injection and adhered to both carotid arteries without vascular compression or invasion. It extended to the suprasellar cistern and compressed the optic chiasm. The diagnosis was nonfunctional pituitary macroadenoma, leading to the decision for Endoscopic Trans-Sphenoidal Surgery (ETSS). A non-sustainable, soft, grayish mass was grossly and totally resected during the operation. Subsequently, there was a significant improvement in visual acuity during the early postoperative period. Histopathologic examination confirmed hemangiopericytoma (WHO grade II).
CONCLUSION
Due to its malignant nature, hemangiopericytoma should be included in the differential diagnosis of a sellar mass, both from a clinical and morphological perspective.
PubMed: 38840972
DOI: 10.3389/fsurg.2024.1359787 -
Vision (Basel, Switzerland) May 2024Neurofibromatosis type 1 (NF1) is an inherited autosomal dominant disorder primarily affecting children and adolescents characterized by multisystemic clinical... (Review)
Review
Neurofibromatosis type 1 (NF1) is an inherited autosomal dominant disorder primarily affecting children and adolescents characterized by multisystemic clinical manifestations. Mutations in neurofibromin, the protein encoded by the tumor suppressor gene, result in dysregulation of the RAS/MAPK pathway leading to uncontrolled cell growth and migration. Neurofibromin is highly expressed in several cell lineages including melanocytes, glial cells, neurons, and Schwann cells. Individuals with NF1 possess a genetic predisposition to central nervous system neoplasms, particularly gliomas affecting the visual pathway, known as optic pathway gliomas (OPGs). While OPGs are typically asymptomatic and benign, they can induce visual impairment in some patients. This review provides insight into the spectrum and visual outcomes of NF1, current diagnostic techniques and therapeutic interventions, and explores the influence of NF1-OPGS on visual abnormalities. We focus on recent advancements in preclinical animal models to elucidate the underlying mechanisms of NF1 pathology and therapies targeting NF1-OPGs. Overall, our review highlights the involvement of retinal ganglion cell dysfunction and degeneration in NF1 disease, and the need for further research to transform scientific laboratory discoveries to improved patient outcomes.
PubMed: 38804352
DOI: 10.3390/vision8020031 -
BMC Medical Genomics May 2024Whole exome sequencing allows rapid identification of causative single nucleotide variants and short insertions/deletions in children with congenital anomalies and/or...
BACKGROUND
Whole exome sequencing allows rapid identification of causative single nucleotide variants and short insertions/deletions in children with congenital anomalies and/or intellectual disability, which aids in accurate diagnosis, prognosis, appropriate therapeutic interventions, and family counselling. Recently, de novo variants in the MED13 gene were described in patients with an intellectual developmental disorder that included global developmental delay, mild congenital heart anomalies, and hearing and vision problems in some patients.
RESULTS
Here we describe an infant who carried a de novo p.Pro835Ser missense variant in the MED13 gene, according to whole exome trio sequencing. He presented with congenital heart anomalies, dysmorphic features, hydrocephalic changes, hypoplastic corpus callosum, bilateral optic nerve atrophy, optic chiasm atrophy, brain stem atrophy, and overall a more severe condition compared to previously described patients.
CONCLUSIONS
Therefore, we propose to expand the MED13-associated phenotype to include severe complications that could end up with multiple organ failure and neonatal death.
Topics: Humans; Mutation, Missense; Male; Phenotype; Mediator Complex; Abnormalities, Multiple; Infant; Infant, Newborn; Syndrome; Exome Sequencing
PubMed: 38745205
DOI: 10.1186/s12920-024-01857-z -
SAGE Open Medical Case Reports 2024Herein, we report a rare case of invasive nasopharyngeal carcinoma with extension to the pituitary gland misdiagnosed as a pituitary macroadenoma. A 50-year-old woman...
Herein, we report a rare case of invasive nasopharyngeal carcinoma with extension to the pituitary gland misdiagnosed as a pituitary macroadenoma. A 50-year-old woman was referred to our department with a diagnosis of pituitary macroadenoma. She presented with headache, visual disturbances, weakness, nausea, vomiting, and hypoglycemia. Polyuria was not reported. On pituitary magnetic resonance imaging, a large mass was observed to extend from the sella turcica to the sphenoid sinus, optic chiasm, and nasopharynx, leading to the initial diagnosis of an invasive pituitary macroadenoma. Biochemical investigations revealed corticotropin deficiency, secondary hypothyroidism, hypogonadotropic hypogonadism, and moderate hyperprolactinemia. Hormone replacement therapy was initiated. After hydrocortisone initiation, diabetes insipidus was revealed. Subsequent magnetic resonance imaging showed an infiltration of the nasopharynx with an extension to the pituitary gland. An endoscopic biopsy confirmed the diagnosis of undifferentiated nasopharyngeal carcinoma. The patient was referred to the oncology department for chemo and radiotherapy. Invasive nasopharyngeal carcinoma presenting with pituitary extension is very rare. It should be considered in the differential diagnosis of pituitary macroadenoma with hypopituitarism. Proper management of such cases requires a multidisciplinary approach.
PubMed: 38715901
DOI: 10.1177/2050313X241252337 -
American Journal of Ophthalmology Case... Jun 2024This report details the characteristics of a case of bilateral optic neuropathy during treatment with oral lorlatinib for ALK-positive metastatic adenocarcinoma of the...
PURPOSE
This report details the characteristics of a case of bilateral optic neuropathy during treatment with oral lorlatinib for ALK-positive metastatic adenocarcinoma of the lung.
OBSERVATIONS
A 57-year-old woman with metastatic adenocarcinoma of the lung receiving treatment with lorlatinib presented to the ophthalmology urgent care with bilateral loss of vision that had progressed to no light perception over the previous 2 weeks. She was hospitalized for an extensive autoimmune, infectious, neoplastic, and paraneoplastic workup, which revealed enhancement of both optic nerves extending up to the optic chiasm and an area of restricted diffusion in the splenium of the corpus callosum on MRI. Lorlatinib was discontinued by her oncologist and she received treatment with five days of pulse-dose intravenous solumedrol as well as five days of plasmapheresis with gradual improvement in her vision. In follow-up, her vision had improved to 20/40 and 20/30.
CONCLUSION AND IMPORTANCE
There have been few reports describing vision loss associated with lorlatinib, an ALK/ROS1 targeted tyrosine kinase inhibitor used to treat metastatic lung adenocarcinoma. This report details the characteristics of a case of bilateral retrobulbar optic neuropathy as well as the treatment and recovery of such a case. Further exploration is needed in order to improve our understanding of the pathogenesis of this rare but potentially devastating adverse effect.
PubMed: 38707952
DOI: 10.1016/j.ajoc.2024.102063 -
Journal of Applied Clinical Medical... May 2024To establish the clinical applicability of deep-learning organ-at-risk autocontouring models (DL-AC) for brain radiotherapy. The dosimetric impact of contour editing,...
PURPOSE
To establish the clinical applicability of deep-learning organ-at-risk autocontouring models (DL-AC) for brain radiotherapy. The dosimetric impact of contour editing, prior to model training, on performance was evaluated for both CT and MRI-based models. The correlation between geometric and dosimetric measures was also investigated to establish whether dosimetric assessment is required for clinical validation.
METHOD
CT and MRI-based deep learning autosegmentation models were trained using edited and unedited clinical contours. Autosegmentations were dosimetrically compared to gold standard contours for a test cohort. D1%, D5%, D50%, and maximum dose were used as clinically relevant dosimetric measures. The statistical significance of dosimetric differences between the gold standard and autocontours was established using paired Student's t-tests. Clinically significant cases were identified via dosimetric headroom to the OAR tolerance. Pearson's Correlations were used to investigate the relationship between geometric measures and absolute percentage dose changes for each autosegmentation model.
RESULTS
Except for the right orbit, when delineated using MRI models, the dosimetric statistical analysis revealed no superior model in terms of the dosimetric accuracy between the CT DL-AC models or between the MRI DL-AC for any investigated brain OARs. The number of patients where the clinical significance threshold was exceeded was higher for the optic chiasm D1% than other OARs, for all autosegmentation models. A weak correlation was consistently observed between the outcomes of dosimetric and geometric evaluations.
CONCLUSIONS
Editing contours before training the DL-AC model had no significant impact on dosimetry. The geometric test metrics were inadequate to estimate the impact of contour inaccuracies on dose. Accordingly, dosimetric analysis is needed to evaluate the clinical applicability of DL-AC models in the brain.
Topics: Humans; Deep Learning; Organs at Risk; Magnetic Resonance Imaging; Radiotherapy Dosage; Tomography, X-Ray Computed; Brain Neoplasms; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated; Radiometry; Image Processing, Computer-Assisted
PubMed: 38664894
DOI: 10.1002/acm2.14345 -
World Journal of Clinical Cases Apr 2024Suprasellar germinomas are rare intracranial tumors frequently associated with permanent endocrine disorders. We present the clinical picture, treatment, and...
BACKGROUND
Suprasellar germinomas are rare intracranial tumors frequently associated with permanent endocrine disorders. We present the clinical picture, treatment, and complications of suprasellar germinoma at pediatric age which, besides being life-threatening, has lifelong endocrinological consequences.
CASE SUMMARY
A 12-year-old female patient was presented having had intensive headaches for three weeks and visual disturbances for six months. An ophthalmological examination revealed bilateral papilledema and a marked loss of vision. Emergency brain magnetic resonance imaging (MRI) showed a suprasellar tumor, involving the infundibulum and the optic chiasm, extending to the third ventricle. Laboratory tests confirmed decreased levels of thyroxine, cortisol, gonadotropins, and insulin-like growth factor 1. Maximal tumor reduction was performed, and immunohistopathology established the diagnosis of suprasellar germinoma. MRI of the spine and cerebrospinal fluid cytology confirmed the localized disease. Adjuvant chemotherapy and radiotherapy were performed according to the SIOP CNS GCT II protocol. A post-treatment MRI showed no residual tumor, but pituitary function had not recovered. Three and a half years after the end of the treatment, the patient is in a complete remission, requiring hormonal replacement therapy, continuous education, and psychological support.
CONCLUSION
This complex case highlights the importance of timely diagnosis, a multidisciplinary approach, and close follow-up in children with suprasellar germinomas.
PubMed: 38660086
DOI: 10.12998/wjcc.v12.i10.1844 -
Qatar Medical Journal 2024The somatostatin analog, pasireotide, is used for the treatment of acromegaly after the failure of surgery and/or first-line medical treatment.
BACKGROUND
The somatostatin analog, pasireotide, is used for the treatment of acromegaly after the failure of surgery and/or first-line medical treatment.
CASE PRESENTATION
A 48-year-old male reported that during a workup for obesity in his home country, hyperprolactinemia was diagnosed and a 3.5 × 3.5 cm pituitary macroadenoma was identified on pituitary MRI. He received cabergoline for 6 months; then he was lost to follow-up. He presented at our Endocrine clinic 2 years later for treatment of obesity (BMI 49.5 kg/m). Biochemical workup revealed that in addition to hyperprolactinemia (7,237 [normal: 85-323 mIU/L), he had acromegaly, evident by elevated insulin-like growth factor 1 (IGF-1) level (450 [normal: 88-210 µg/L]), and a positive growth hormone suppression test, secondary hypothyroidism, and secondary hypogonadism. Pituitary MRI showed that the adenoma encased parts of the left and right internal carotid arteries and encroached on the optic chiasm. Surgical excision was therefore not feasible. He was treated with cabergoline and later, long-acting release (LAR) octreotide. Prolactin levels were reduced with cabergoline, but IGF-1 levels did not respond to octreotide, and it was discontinued. The patient abandoned radiotherapy after two sessions. He was started on LAR pasireotide 40 mg every 4 weeks and continued on cabergoline 0.5 mg per week. His biochemical response was dramatic, with a near normalization of IGF-1 levels in 3 months. After 6 months from starting pasireotide, we increased cabergoline dose from 0.5 mg/week to 3 mg/week. Three months later, IGF-1 level was normalized. The patient developed type 2 diabetes as a side effect of pasireotide; however, this was well-controlled with medications.
CONCLUSIONS
The case suggests that pasireotide can provide marked biochemical improvement in acromegaly after the failure of both cabergoline monotherapy and cabergoline plus octreotide. This further confirms a potentially efficacious treatment regimen in treatment-resistant acromegaly with hyperprolactinemia.
PubMed: 38654814
DOI: 10.5339/qmj.2024.17