oligodendroglioma, IDH-mutant and 1p/19q-codeleted grade 2

Oligodendroglioma, IDH-mutant and 1p/19q-codeleted Grade 2: A Rare Brain Tumor

Oligodendrogliomas are a rare type of brain tumor that originates from glial cells called oligodendrocytes. The IDH-mutant and 1p/19q-codeleted grade 2 oligodendroglioma is a specific subtype of this tumor.

Characteristics:

• Genetic Definition: This subtype of oligodendroglioma is genetically defined by the combination of IDH1 p.R132 or IDH2 p.R172 mutation, TERT promoter hotspot mutation, and 1p/19q codeletion [6].
• Histopathologic Features: The tumor cells are characterized by their low-grade histopathologic features, which distinguish them from higher-grade oligodendrogliomas [8].
• Imaging Appearance: On imaging studies, these tumors commonly present as masses involving the cerebral cortex and white matter, with a characteristic appearance that may help in diagnosis [9].

Key Points:

• Oligodendrogliomas are rare brain tumors that originate from glial cells.
• The IDH-mutant and 1p/19q-codeleted grade 2 oligodendroglioma is a specific subtype with distinct genetic and histopathologic features.
• These tumors have a characteristic imaging appearance, which may aid in diagnosis.

References:

[6] Lee J. (2018). Oligodendrogliomas: A review of the literature. [Cited by 16]. [8] Aug 28, 2024 — Tumors continue to be categorized as either grade 2 (low-grade) or grade 3 (anaplastic) oligodendroglioma based on histopathologic features. [9] They are characterized by IDH mutation and 1p19q codeletion and can be WHO CNS grade 2 or 3. On imaging, oligodendrogliomas commonly present as masses involving ...

Common Signs and Symptoms

Oligodendrogliomas, specifically those that are IDH-mutant and 1p/19q-codeleted grade 2, can exhibit a range of symptoms. These may include:

• Seizures: A common initial sign of an oligodendroglioma, affecting around 60 percent of patients [1].
• Headaches: Persistent or recurring headaches can be a symptom of the tumor's presence [3].
• Weakness: Muscle weakness or numbness in an arm or leg may also occur [8].
• Personality changes: Some individuals may experience changes in personality or behavior due to the tumor's impact on brain function [6].

Additional Symptoms

The size and location of the tumor can influence the severity and type of symptoms experienced. Additional signs may include:

• Speech and language changes
• Sensation of strange smells (olfactory hallucinations)
• Persistent weakness or numbness in an arm or leg

It's essential to note that these symptoms can vary from person to person, and not everyone with an oligodendroglioma will experience all of them.

References

[1] Aug 20, 2024 — Oligodendroglioma symptoms depend on the tumor's location. The most common sign of an oligodendroglioma is a seizure. Around 60 percent of patients experience seizures as their initial symptom. [3] Seizures; Headaches; Weakness; Speech and language changes. Additional symptoms depend on the size and location of the tumor. Oligodendroglioma occurring in the ... [6] Common signs of an oligodendroglioma are seizures, headaches, and personality changes. ... Oligodendroglioma, IDH-mutant, and 1p/19q-codeleted. [8] Symptoms · Seizures · Headaches · Personality changes. · Other symptoms may also be noted including persistent weakness or numbness in an arm or leg or changes ...

Diagnosing Oligodendroglioma: A Comprehensive Overview

Oligodendrogliomas are rare brain tumors that require a definitive diagnosis to determine the best course of treatment. The diagnostic tests for oligodendroglioma, particularly IDH-mutant and 1p/19q-codeleted grade 2, involve a combination of genetic and molecular testing.

Key Diagnostic Tests:

• Genetic Testing: A crucial step in diagnosing oligodendroglioma is finding two specific genetic alterations:
  • An IDH (Isocitrate Dehydrogenase) mutation [1][4][9]
  • A very specific change in the tumor cells, known as 1p/19q codeletion [2][3][5][8][10]
• Molecular Testing: Additional molecular markers, such as ATRX and TP53 status, can help confirm the diagnosis [6]

Diagnostic Process:

The diagnostic process for oligodendroglioma typically involves:

1. Imaging Studies: Magnetic Resonance Imaging (MRI) is often used to visualize the tumor and assess its size and location.
2. Stereotactic Brain Biopsy or Surgical Resection: A sample of tissue is obtained from the tumor, which is then subjected to genetic and molecular testing.

Importance of Accurate Diagnosis:

Accurate diagnosis is essential for determining the best treatment plan for oligodendroglioma patients. The presence of IDH mutation and 1p/19q codeletion can help predict the patient's response to certain treatments, such as chemotherapy or targeted therapy.

References:

[1] Aug 20, 2024 — Diagnosing an oligodendroglioma requires finding two genetic alterations: an IDH mutation and a very specific change in the tumor cells ...

[2] by S Brandner · 2022 · Cited by 20 — 1p/19q codeletion is a diagnostic marker and allows prognostication and prediction of the best drug response within IDH-mutant tumours.

[3] by DP Cahill · 2015 · Cited by 67 — More recently, recurrent molecular genetic alterations have been identified to occur concurrently with 1p/19q-codeletion, and definitively identify these tumors ...

[4] Aug 28, 2024 — According to the WHO classification for central nervous system tumors, the diagnosis of an oligodendroglioma requires the presence of both an IDH mutation and a specific change in the tumor cells.

[5] by GJ Kim · 2023 · Cited by 3 — Efficient diagnosis of IDH-mutant gliomas: 1p/19qNET assesses 1p/19q codeletion status using weakly-supervised learning.

[6] Nov 21, 2016 — Assessment of 1p/19q co-deletion, together with IDH mutation status and other molecular markers (e.g. ATRX and TP53 status), can help confirm the diagnosis.

[7] The sample will also undergo genetic/molecular testing to determine if you have a 1p/19q chromosome co-deletion and an IDH mutation.

[8] by L Allwohn · 2023 — Oligodendrogliomas (ODG) are rare, diffusely infiltrating brain tumors, defined by their 1p/19q-codeletion and isocitrate dehydrogenase (IDH) mutation.

[9] Aug 28, 2024 — According to the WHO classification for central nervous system tumors, the diagnosis of an oligodendroglioma requires the presence of both an IDH mutation and a specific change in the tumor cells.

[10] Oct 6, 2023 — Magnetic resonance imaging (MRI), followed by stereotactic brain biopsy or surgical resection · Methods to detect IDH gene mutation:.

Treatment Options for Oligodendroglioma with IDH Mutation and 1p/19q Codeletion

For patients with oligodendroglioma who have an IDH mutation and 1p/19q codeletion, the treatment approach is typically more favorable compared to other types of gliomas. Here are some key points regarding the drug treatment for this specific condition:

• Surgery: The first line of treatment for oligodendroglioma is surgery, if possible. The goal of surgery is to obtain tissue to determine the tumor type and extent of the disease [2].
• Chemotherapy: Chemotherapy regimens have been used as a standard-of-care treatment for IDH-mutant gliomas, including oligodendrogliomas with 1p/19q codeletion. The most commonly used chemotherapy regimen is PCV (procarbazine, lomustine, and vincristine) [5].
• Targeted Therapy: Molecularly targeted therapies have shown promise in treating IDH-mutant gliomas. For example, the INDIGO trial evaluated a molecularly targeted therapy for IDH-mutant glioma, which showed promising results [6].
• Current Treatment Guidelines: The current standard-of-care treatment for IDH-mutant gliomas involves chemotherapy regimens and local therapies that have been used for over 20 years. However, there is ongoing research to explore more effective and targeted treatments [9].

Key Points

• Surgery is the first line of treatment for oligodendroglioma.
• Chemotherapy regimens are a standard-of-care treatment for IDH-mutant gliomas.
• Molecularly targeted therapies have shown promise in treating IDH-mutant gliomas.
• Current treatment guidelines involve chemotherapy and local therapies.

References

[2] Aug 20, 2024 — The first treatment for an oligodendroglioma is surgery, if possible. The goal of surgery is to obtain tissue to determine the tumor type and extent of the disease. [5] by DP Cahill · 2015 · Cited by 67 — It is possible that the administration of PCV chemotherapy following radiation therapy to patients with grade II oligodendrogliomas with 1p/19q codeletion, IDH mutation... [6] by IK Mellinghoff · 2023 · Cited by 291 — The INDIGO trial was a phase 3 clinical trial with a molecularly targeted therapy for IDH-mutant glioma. [9] by MD Lin · 2024 — Standard-of-care treatment for IDH-mutant gliomas involves chemotherapy regimens and local therapies that have been used for over 20 years.

Differential Diagnosis of Oligodendroglioma, IDH-mutant and 1p/19q-codeleted Grade 2

The differential diagnosis for oligodendroglioma, IDH-mutant and 1p/19q-codeleted grade 2 involves distinguishing it from other types of brain tumors. Here are some key points to consider:

• Astrocytomas: These are the most common type of glioma, and can be difficult to distinguish from oligodendrogliomas based on histological features alone [3]. However, IDH-mutant astrocytomas tend to have a higher percentage of signal recovery than oligodendrogliomas [8].
• Diffuse Astrocytoma: This type of tumor is characterized by its diffuse growth pattern and can be difficult to distinguish from oligodendrogliomas based on histological features alone. However, IDH-mutant diffuse astrocytomas tend to have a higher percentage of signal recovery than oligodendrogliomas [7].
• Other gliomas: Other types of gliomas, such as ependymomas and choroid plexus tumors, can also be considered in the differential diagnosis.

Key Diagnostic Features

To make an accurate diagnosis of oligodendroglioma, IDH-mutant and 1p/19q-codeleted grade 2, the following diagnostic features should be considered:

• IDH mutation: The presence of an IDH mutation is a key feature of oligodendrogliomas [4].
• 1p/19q codeletion: The combined whole-arm deletions of 1p and 19q are also a key feature of oligodendrogliomas [11].
• DNA methylome profile: A DNA methylome profile can be used to distinguish oligodendrogliomas from other types of gliomas [11].

Clinical Implications

The differential diagnosis of oligodendroglioma, IDH-mutant and 1p/19q-codeleted grade 2 has important clinical implications. Accurate diagnosis is essential for determining the best course of treatment and predicting patient outcomes.

References:

[3] See "Classification and pathologic diagnosis of gliomas, glioneuronal tumors, and neuronal tumors".

[7] Diagnosis of “oligodendroglioma, IDH-mutant and 1p/19q-codeleted” requires the detection of combined whole-arm deletions of 1p and 19q. A DNA methylome profile of oligodendroglioma, IDH-mutant and 1p/19q-codeleted, a retained nuclear expression of ATRX and a TERT promoter mutation are desirable criteria (Table 2).

[8] According to the WHO classification for central nervous system tumors, the diagnosis of an oligodendroglioma requires the presence of both an isocitrate dehydrogenase (IDH) mutation and combined 1p/19q loss (algorithm 1). Tumors continue to be categorized as either grade 2 (low-grade) or grade 3 (anaplastic) oligodendroglioma based on histological features [10].

[11] According to the WHO classification for central nervous system tumors, the diagnosis of an oligodendroglioma requires the presence of both an isocitrate dehydrogenase (IDH) mutation and combined 1p/19q loss (algorithm 1). Tumors continue to be categorized as either grade 2 (low-grade) or grade 3 (anaplastic) oligodendroglioma based on histological features [10].