With approximately 12,500 deaths and 20,500 new cases every year in the United States, gliomas are the most common primary tumors of the brain [1] [2]. Although numerous risk factors of various origins have been proposed (such as viral infections by varicella zoster virus - VZV and cytomegalovirus - CMV, genetic predisposition, nonionizing radiation from cellular phones, etc.), occupational exposure to pesticides or organic solvents and ionizing radiation have the strongest association with the development of gliomas [1] [2] [3] [4]. These tumors are encountered in two age groups - In the first decade of life (0-8 years) and in late adulthood/the elderly (50-70 years of age) [1]. The clinical presentation can vary widely depending on the tumor location, but the two main symptoms are convulsions and a decrease in cognitive function [5]. In addition, memory and speech deficits, gait disturbances, headaches, nausea, vomiting, visual and/or auditory impairment, as well as personality changes are all mentioned in the literature as possible symptoms of gliomas [1] [6]. Furthermore, tumors originating from the brainstem produce an array of clinical signs, including cranial nerve palsies (predominantly of the V, VI, and VIII) and pyramidal weakness [4]. Progression of symptoms can be either slow or rapid, depending on the subtype. An early diagnosis is mandatory in either case, however, survival rates for gliomas diagnosed in the most advanced stages rarely exceed 1 year [6].

Having in mind the very poor prognosis of late-stage gliomas, all patients with the undisclosed central nervous system (CNS)-related symptoms must be evaluated in a thorough manner. Firstly, the course of symptoms should be noted during history taking, whereas a meticulous physical examination, with an emphasis on the neurological exam and cognitive assessment, can provide vital clues about the location of the lesion. Imaging studies are the cornerstone of diagnosing gliomas. Magnetic resonance imaging (MRI), sometimes supported by magnetic resonance spectroscopy (MRS), is the modality of choice in identifying the exact site of the tumor and in determining the extent of tissue and nodal invasion [1] [4]. To confirm the diagnosis, however, a biopsy and a histopathological examination are necessary, which aids in classifying tumor into one of its three main categories [1] [2] [3] [5] [6]:

• Astrocytomas - Encompassing about 80% of all gliomas, astrocytomas are diagnosed either as low-grade tumors of limited proliferative capacities (stage I), or as highly malignant lesions (well-differentiated, anaplastic, and glioblastoma multiforme are terms used to describe stages II, III and IV, respectively) [1] [3] [6]. The two main forms are diffuse (malignant) and pilocytic (more often benign), and the distinguishing feature of astrocytomas on pathohistological examinations is the positive staining for glial fibrillary acidic protein (GFAP) on immunohistochemistry [1] [6].
• Oligodendrogliomas - Contrary to astrocytomas, oligodendrogliomas are principally benign tumors arising in the frontal lobes of the cerebral cortex. This tumor, based on its histological characteristics, is classified into stage II, but more severe anaplastic forms (stage III) carry a somewhat poorer prognosis, although the outcome is much better compared to astrocytomas [1] [6].
• Ependymomas - These tumors are very rarely encountered and comprise about 5-10% of all gliomas, developing in close proximity of the fourth ventricle in the majority of case.

Treatment for glioma depends on the tumor's type, location, and grade. Options may include surgery to remove as much of the tumor as possible, followed by radiation therapy and chemotherapy to target remaining cancer cells. In some cases, targeted therapies or clinical trials may be available. The treatment plan is often tailored to the individual patient, considering factors such as age and overall health.

The prognosis for glioma varies widely based on the tumor's grade and location. Low-grade gliomas generally have a better prognosis and may be managed successfully for many years. High-grade gliomas, such as glioblastoma, tend to have a more aggressive course and a poorer prognosis. Advances in treatment are continually improving outcomes, but gliomas remain challenging to treat.

The exact cause of glioma is not well understood. However, certain risk factors have been identified, including genetic predispositions and exposure to ionizing radiation. Some hereditary syndromes, such as neurofibromatosis, are associated with an increased risk of developing gliomas. Research is ongoing to better understand the genetic and environmental factors involved in glioma development.

Gliomas account for approximately 30% of all brain tumors and 80% of malignant brain tumors. They can occur at any age but are most commonly diagnosed in adults between the ages of 45 and 65. There is a slight male predominance. The incidence of gliomas varies globally, with higher rates observed in North America and Europe compared to Asia and Africa.

Gliomas arise from glial cells, which include astrocytes, oligodendrocytes, and ependymal cells. These tumors are characterized by uncontrolled cell growth and the ability to invade surrounding brain tissue. High-grade gliomas often exhibit genetic mutations that drive their aggressive behavior. Understanding the molecular pathways involved in glioma pathogenesis is crucial for developing targeted therapies.

Currently, there are no established methods for preventing gliomas. Reducing exposure to known risk factors, such as ionizing radiation, may lower the risk. Ongoing research aims to identify potential preventive strategies, including lifestyle modifications and early detection in high-risk individuals. Public health efforts focus on raising awareness and promoting research into the causes and prevention of brain tumors.

Glioma is a complex and diverse group of brain tumors originating from glial cells. The disease presents with a range of symptoms and requires a comprehensive diagnostic workup to determine the appropriate treatment strategy. While advances in medical research are improving outcomes, gliomas remain a significant challenge due to their aggressive nature and the critical areas they affect in the brain.

If you or a loved one is diagnosed with glioma, it is important to understand the nature of the disease and the available treatment options. Gliomas can vary greatly in their behavior and impact on health. Working closely with a healthcare team, including neurologists, oncologists, and neurosurgeons, can help manage the condition effectively. Support groups and counseling services are also valuable resources for patients and families navigating this challenging diagnosis.

1. Gladson CL, Prayson RA, Liu W (Michael). The Pathobiology of Glioma Tumors. Annual review of pathology. 2010;5:33-50.
2. Schwartzbaum JA, Fisher JL, Aldape KD, Wrensch M. Epidemiology and molecular pathology of glioma. Nat Clin Pract Neurol. 2006;2(9):494-503.
3. Ostrom QT, Bauchet L, Davis FG, et al. The epidemiology of glioma in adults: a “state of the science” review. Neuro-Oncology. 2014;16(7):896-913.
4. Reyes-Botero G, Mokhtari K, Martin-Duverneuil N, Delattre J-Y, Laigle-Donadey F. Adult Brainstem Gliomas. Oncologist. 2012;17(3):388-397.
5. Posti JP, Bori M, Kauko T, et al. Presenting symptoms of glioma in adults. Acta Neurol Scand. 2015 Feb;131(2):88-93.
6. Aster, JC, Abbas, AK, Robbins, SL, Kumar, V. Robbins basic pathology. Ninth edition. Philadelphia, PA: Elsevier Saunders; 2013.