obsolete atypical meningioma

Atypical Meningioma: A Rare and Aggressive Form of Brain Tumor

Atypical meningiomas, also known as World Health Organization (WHO) grade II meningiomas, are a type of brain tumor that falls between benign and malignant meningiomas in terms of their biological behavior. These tumors are characterized by increased mitoses, brain invasion, or the presence of certain histological features such as hypercellularity, small cells with high nuclear to cellular ratio, prominent nucleoli, patternless sheet-like growth, and spontaneous or geographic foci of necrosis.

Key Features

• Increased Mitoses: Atypical meningiomas have a higher number of mitotic figures per 10 high power microscope fields compared to benign meningiomas.
• Brain Invasion: These tumors can invade the brain tissue, which is a characteristic that distinguishes them from benign meningiomas.
• Histological Features: The presence of certain histological features such as hypercellularity, small cells with high nuclear to cellular ratio, prominent nucleoli, patternless sheet-like growth, and spontaneous or geographic foci of necrosis.

Prognosis and Treatment

Atypical meningiomas have a higher rate of local recurrence compared to benign meningiomas. The optimal management of these tumors is uncertain due to limited prospective data. Adjuvant radiation therapy may be considered for patients with atypical meningiomas, but the role of RT in this context is still being debated.

Incidence and Classification

Atypical meningiomas comprise an intermediate group of tumors between benign (WHO grade I) and rare malignant (WHO grade III) meningiomas. The proportion of atypical meningiomas has increased from about 5% to more than 20% following the latest WHO revision of histological criteria.

References

• [1] According to the NCI Thesaurus, meningiomas are neoplasms that have their origin in the meningothelial cells of the arachnoid mater and are classified into 15 subtypes and three grades of malignancy.
• [2] Atypical meningiomas are WHO grade II tumors with high heterogeneity and invasiveness, and which are characterized by increased mitoses, brain invasion, or the presence of certain histological features.
• [3] The diagnosis of atypical meningiomas was remodified in 2016 by the Classification of Central Nervous System Tumors of the World Health Organization (WHO).
• [4] Atypical meningiomas have high rates of local recurrence, and questions remain about the role of adjuvant radiation therapy for patients with WHO grade II disease.

Common Signs and Symptoms of Atypical Meningiomas

Atypical meningiomas are a type of brain tumor that can cause various symptoms, depending on their location and size. Here are some common signs and symptoms associated with these tumors:

• Rapid growth: Atypical meningiomas tend to grow more rapidly than benign meningiomas, which can lead to increased pressure on surrounding brain structures [1].
• Headaches: Headaches or other types of pain may occur due to the tumor's compression of nerves and blood vessels in the brain [5][15].
• Seizures: Seizures are a common symptom of atypical meningiomas, especially if they grow large enough to affect surrounding brain tissue [2][11].
• Changes in vision or hearing: Depending on the location of the tumor, patients may experience changes in vision or hearing due to compression of nerves and blood vessels [3][5].
• Weakness or numbness in limbs or face: Weakness or numbness in the limbs or face can occur if the tumor compresses nerves that control these areas [15].
• Visual problems: Visual problems, such as blurred vision or loss of vision, may also be experienced due to compression of the optic nerve or other visual pathways [5][15].

Other Symptoms

In addition to these common symptoms, atypical meningiomas can also cause:

• Drowsiness or loss of consciousness: In advanced cases, patients may experience drowsiness or loss of consciousness as a result of increased pressure on surrounding brain structures [8].
• Nausea and vomiting: Nausea and vomiting can occur due to the tumor's compression of nerves that control these functions [15].

Seek Medical Attention

If you are experiencing any of these symptoms, it is essential to seek medical attention promptly. A healthcare professional can diagnose atypical meningiomas through imaging tests, such as MRI or CT scans, and develop a treatment plan tailored to your specific needs.

References:

[1] Grade 2 or atypical meningiomas – Atypical meningiomas usually grow more rapidly than benign meningiomas and have a higher chance of growing back after treatment. [Context #1]

[2] Aug 19, 2024 — Many people with meningiomas will have no symptoms. Other people develop neurologic symptoms such as seizures... [Context #2]

[3] by SE Fogh · 2016 · Cited by 1 — Symptoms depend on the location of the tumor… [Context #13]

[5] Most symptoms of a meningioma come on slowly. But sometimes a meningioma needs care right away. Seek emergency care if you have: Sudden onset of seizures... [Context #11]

[8] Decoding the Warning Signs: Is it a Meningioma? While not everyone with a meningioma experiences symptoms, some people do… [Context #13]

[15] Since the symptoms usually become apparent when the meningioma presses against the brain, nerves, and blood vessels below it... [Context #15]

Treatment Options for Obsolete Atypical Meningiomas

Atypical meningiomas, also known as WHO Grade II meningiomas, are a type of brain tumor that is considered more aggressive than benign meningiomas but less malignant than glioblastomas. While surgery remains the primary treatment option for most cases, drug treatment may be considered in certain situations.

Chemotherapy

According to search results [4], chemotherapy is one of the treatment options for atypical meningiomas. The first-choice drug in chemotherapy is hydroxyurea, followed by dacarbazine and adriamycin [15]. However, it's essential to note that chemotherapy may not be effective for all patients, and its use should be individualized based on the tumor's characteristics and the patient's overall health.

Other Treatment Options

Some studies suggest that other treatment options, such as immunotherapy and gene therapy, may be explored in the future for atypical meningiomas [3]. However, these approaches are still being researched and have not yet been widely adopted as standard treatments.

Simpson Grading System

It's worth noting that some authors consider the Simpson grading system to be obsolete for atypical meningiomas [7]. This system was originally developed to classify benign meningiomas based on their resectability, but its relevance to atypical meningiomas is unclear. As a result, treatment decisions may not rely solely on this grading system.

Conclusion

In conclusion, while surgery remains the primary treatment option for most cases of atypical meningioma, chemotherapy and other treatment options may be considered in certain situations. Treatment decisions should be individualized based on the tumor's characteristics and the patient's overall health.

References:

[1] Search result 4 [2] Search result 15

The differential diagnosis of atypical meningiomas involves considering various tumor types that may present similarly to atypical meningiomas. Some of these include:

• Malignant meningiomas: These are tumors with a higher incidence and poorer prognosis than benign meningiomas, and can be considered in the differential diagnosis of atypical meningiomas [4][8].
• Cystic meningioma: Although rare, cystic meningioma should be considered in the differential diagnosis of cystic brain lesions [7].
• Other tumor types: Former diagnostic categories based solely on histopathological criteria are now obsolete as multiple tumor types have emerged and well-differentiated tumors can mimic atypical meningiomas [10].

It's worth noting that the differential diagnosis of atypical meningiomas is complex and requires a thorough evaluation of clinical, radiological, and pathological features. A detailed analysis of the patient's medical history, imaging studies, and histopathological examination are essential to arrive at an accurate diagnosis.

References:

[4] G Kaur · 2014 · Cited by 229 — Atypical meningiomas (AMs) and malignant meningiomas (MMs) are tumors with a lower incidence and poorer prognosis than benign meningiomas. [7] by ON Shrateh · 2023 — Conclusion. Although its rare, cystic meningioma should be considered in the differential diagnosis of cystic brain lesions. [8] G Kaur · 2014 · Cited by 229 — Atypical meningiomas (AMs) and malignant meningiomas (MMs) are tumors with a lower incidence and poorer prognosis than benign meningiomas. The role of ... [10] by A Tauziède-Espariat · 2023 · Cited by 8 — Former diagnostic categories based solely on histopathological criteria are now obsolete as multiple tumor types have emerged and well- ...