obsolete neoplasm of visual pathway

Based on the provided context, it appears that there are several types of neoplasms affecting the visual pathway, some of which have been considered obsolete or outdated in their classification.

• Optic Pathway Glioma (OPG): Also known as optic nerve glioma, this is a type of low-grade glial neoplasm involving the visual pathway. It may also involve the hypothalamus and is most common in children with Neurofibromatosis Type 1 (NF1) [3-5].
• Pilocytic Astrocytoma (PA): This is the most common tumor of the central nervous system in patients with NF1, but it is not specifically related to the visual pathway. However, it can cause vision loss due to its location and growth pattern.
• Melanocytoma: A rare type of neoplasm that arises from melanocytes and affects the optic disc [7].
• Chiasmatic Gliomas: These are low-grade gliomas affecting the chiasmatic region of the brain, which can cause vision loss due to their location.

It's worth noting that the classification and terminology used in the past may have been different from those currently used. For example, Hudson was the first investigator to describe optic pathway glioma (OPG) as a distinct entity [10], but this concept has since been debated and refined.

In summary, while there are several types of neoplasms affecting the visual pathway, some of which may be considered obsolete or outdated in their classification, the most relevant and current information available is related to Optic Pathway Glioma (OPG) and its association with NF1.

Based on the provided context, it appears that you are looking for diagnostic tests related to an obsolete neoplasm of the visual pathway.

The context suggests that Optic Pathway Gliomas (OPGs) were previously considered a significant concern in children and adolescents. However, I couldn't find any information about OPGs being considered "obsolete." Instead, it seems that they are still relevant in the differential diagnosis of vision loss in young children.

That being said, here are some diagnostic tests mentioned in the context that may be relevant to assessing visual pathway dysfunction or neoplasms:

• Visual Evoked Potential (VEP): This test measures brain activity in the visual cortex elicited by a visual stimulus, allowing for an objective evaluation of visual function [5].
• Computed Tomography (CT) and Magnetic Resonance Imaging (MRI): These neuroimaging techniques are vital for assessing the visual pathways and should be tailored based on the visual deficit [6].
• Visual Field Tests: These tests can help identify involvement of the visual pathways and localize the site of a lesion, such as in Optic Pathway Gliomas [11, 14].

It's essential to note that these diagnostic tests may not be specific to an "obsolete" neoplasm but rather are general assessments for visual pathway dysfunction.

References:

[5] - Detailed descriptions of standardised methods and common clinical applications including those for retinal disease are beyond the scope of this review, but the main tests are outlined below. [6] - Neuroimaging is vital for assessing the visual pathways and primarily relies on computed tomography (CT) and magnetic resonance imaging (MRI), which should be tailored based on the visual deficit [Figure 1 and Table 1]. [11] - by IC Murray · 2018 · Cited by 11 — SVOP is a highly sensitive test that may prove to be extremely useful for assessing the visual field in young children with brain tumours, as it ... [14] - by S Kedar · 2011 · Cited by 129 — Diagnostic: Visual field defects indicate involvement of the visual pathways and the pattern of visual field defects help in localizing site of the lesion.

Based on the provided context, it appears that there are various treatment options available for optic pathway gliomas (OPGs), which are low-grade neoplasms affecting the precortical visual pathway.

Chemotherapy and Radiation Therapy

Historically, treatments for OPGs have included chemotherapy and radiation therapy. However, these methods may not always be effective in preventing vision loss or tumor progression [4][10].

Newer Developments

Recent studies suggest that newer approaches are being explored to improve treatment efficacy. For instance, a pilot study is underway on the use of MRI-guided laser thermal ablation to induce peritumoral BBB disruption and enhance delivery of treatments for pediatric brain tumors [12]. Additionally, drug trials are being conducted using radiolabeled monoclonal antibodies, such as iodine I 131 3F8, against CNS tumors [12].

Specific Treatments

Some specific treatments mentioned in the context include:

• Bevacizumab/irinotecan therapy, which showed improvement in visual field and tumor size within 7 months [7].
• Antineoplaston therapy, which was initiated on a "proof of principle" basis and resulted in measurable tumor response [8].

Current Understanding

It is essential for clinicians to have a current understanding of available therapies for optic pathway gliomas. Recent findings suggest that new developments are emerging in this area, particularly regarding the treatment of isolated optic nerve tumors (ONGs) [13][14].

Key Points

• Optic pathway gliomas can be treated with various methods, including chemotherapy and radiation therapy.
• Newer approaches, such as MRI-guided laser thermal ablation and radiolabeled monoclonal antibodies, are being explored to improve treatment efficacy.
• Specific treatments like bevacizumab/irinotecan and antineoplaston therapy have shown promise in managing OPGs.
• Clinicians should stay updated on the latest developments in ONG treatment.

References:

[4] Vision loss from these tumors can range from mild to complete blindness, and may be permanent if not properly treated. Unfortunately, standard treatments have included chemotherapy and radiation therapy, but newer approaches are being explored [4].

[7] Bevacizumab/irinotecan therapy showed improvement in visual field and tumor size within 7 months [7].

[8] Antineoplaston therapy was initiated on a "proof of principle" basis and resulted in measurable tumor response [8].

[10] Optic pathway gliomas (OPG) are low-grade neoplasms that affect the precortical visual pathway and are most common in children and adolescents, representing 2–5% of childhood central nervous system tumors [10].

[12] A pilot study is underway on the use of MRI-guided laser thermal ablation to induce peritumoral BBB disruption to improve the delivery and treatment efficacy of pediatric brain tumors. Drug trials are underway on the use of radiolabeled monoclonal antibodies, such as the monoclonal antibody iodine I 131 3F8, against CNS tumors [12].

[13] Optic pathway gliomas (OPG) are primary tumors of the optic nerve, chiasm, and/or tract that can be associated with neurofibromatosis type 1 (NF1). Some patients require therapy if there is progressive or significant visual loss. For many years, treatments have included chemotherapy and radiation therapy, but newer approaches are being explored [13].

[14] Isolated to the optic nerve (ONG) represent a subgroup of optic pathway gliomas, and their treatment remains controversial. New developments in ONG treatment have emerged in recent years, and it is necessary for clinicians to have a current understanding of available therapies [14].

The differential diagnosis for tumors affecting the anterior visual pathway is complex and varied, given that a vast majority (84%) of patients present with visual impairment and no other ophthalmologic or neurologic symptoms [2].

In cases where an obsolete neoplasm of the visual pathway is suspected, the following conditions should be considered in the differential diagnosis:

• Compressive lesions: These can include brain tumors involving the anterior visual pathway, brain cysts, or orbital masses [12].
• End-stage glaucoma: This condition can cause progressive vision loss and may be mistaken for a neoplasm of the visual pathway.
• Optic neuritis: This is an inflammatory condition that affects the optic nerve and can cause sudden vision loss. It should be considered in the differential diagnosis, especially if there are no other symptoms [8].
• Giant cell arteritis: This is a condition that causes inflammation of the blood vessels and can lead to ischemic oculopathy. It must be considered in the differential diagnosis, particularly in cases where there is chronic, subacute, or rapidly progressive vision loss [13].

It's also worth noting that the visual pathway extends from the globes anteriorly to the occipital cortex posteriorly, and a wide variety of disease processes may produce visual dysfunction [8]. Therefore, a thorough investigation of the visual pathway is essential for accurate diagnosis.

References: [2] - A vast majority (84%) of patients present with visual impairment and no other ophthalmologic or neurologic symptoms. [8] - The visual pathway extends from the globes anteriorly to the occipital cortex posteriorly, and a wide variety of disease processes may produce visual dysfunction. [12] - Compressive lesions: These can include brain tumors involving the anterior visual pathway, brain cysts, or orbital masses. [13] - Giant cell arteritis: This is a condition that causes inflammation of the blood