Definition

A Space Occupying Lesion (SOL) is an abnormal lesion occupying space in the brain, usually resulting from malignancy, but it can also be caused by other conditions such as abscesses or hematomas. These lesions can infiltrate and damage important brain structures, impede cerebrospinal fluid flow and cause hydrocephalus, or induce angiogenesis (the process of forming new blood vessels), which can disrupt the blood-brain barrier and cause edema.

Malignancies of the brain are classified as primary and secondary brain tumors. A primary brain tumor originates from the growth of tissue within the brain itself, and the majority of these tumors are benign. On the other hand, secondary or metastatic brain tumors occur when cancerous cells from other parts of the body spread to the brain, as is often the case with advanced-stage lung cancer or breast cancer, which begin to extend their reach to other organs in the body.

Causes

The causes of SOL can be grouped into:

Malignancy

Examples include metastasis from other cancers to the brain, gliomas, meningiomas, pituitary adenomas, and acoustic neuromas, which account for 95% of all brain tumors. In adults, two-thirds of primary brain tumors are located in the supratentorial area (above the tentorium, i.e., the cerebrum), while in children, two-thirds are in the infratentorial area (below the tentorium, i.e., the cerebellum).

Primary brain tumors like astrocytomas, glioblastoma multiforme, oligodendrogliomas, and ependymomas typically do not metastasize to other organs. The most common tumors that metastasize to the brain are lung tumors, followed by breast tumors, colon cancer, and malignant melanoma.

Cysts

Cysts that can cause SOL include arachnoid cysts, colloid cysts, dermoid cysts, and epidermoid cysts.

Hematoma

Other causes of SOL besides malignancy and cysts include hematomas, which are collections of blood outside blood vessels. These can result from head trauma, hydrocephalus, and cerebral abscesses. Though rare, cerebral abscesses can occur in patients with chronic obstructive pulmonary disease (COPD), which is a source of infection.

Infection

Cerebral amoebiasis and cysticercosis can cause SOL, though they are rare. HIV infection, granulomas, and tuberculomas can also lead to SOL.

Risk factor

Several factors can increase the risk of developing SOL:

• Age (some brain tumors are more common in children)
• Genetic factors such as Gorlin syndrome, Turcot syndrome, and neurofibromatosis types 1 and 2
• History of head trauma
• History of radiotherapy
• History of infectious diseases such as COPD, which can trigger cerebral abscesses, or pulmonary tuberculosis, which can lead to tuberculoma
• Overweight or obesity can increase the risk of meningioma

Symptoms

Symptoms of brain tumors vary depending on the lesion's location. The brain is divided into four lobes: temporal, frontal, parietal, and occipital. For example, if the SOL is in the temporal lobe, it can trigger symptoms like depersonalization, emotional changes, and behavioral disturbances. Temporal lobe epilepsy can cause olfactory, gustatory, auditory, and visual hallucinations. Other symptoms such as vision loss, forgetfulness, dissociative fugue, and inappropriate sexual behavior may also occur.

A tumor in the frontal lobe can cause anosmia, personality changes (inappropriate, unwise, or dishonest behavior), dysphasia, and hemiparesis (partial body weakness). A tumor located at the optic chiasm, such as a pituitary adenoma, can cause bitemporal hemianopia (blindness in the outer parts of both eyes).

Lesions in the occipital lobe predominantly cause eye symptoms. Symptoms like papilledema or optic nerve swelling can be seen during an eye examination. This symptom may be more apparent in children than adults.

Headache can be a symptom of SOL. Brain tumor headaches are typically very painful in the morning and worsen when bending down. Brain tumor headaches differ from other types such as tension headaches or migraines. Changes in headache patterns or frequency often occur with brain tumors. Headaches are more common with tumors located at the back of the head and rapidly growing tumors.

Vomiting, sometimes without nausea, can occur. In SOL, projectile vomiting can result from increased brain pressure, which can also cause papilledema.

Other symptoms may include mental status changes, weakness, gait disturbances (ataxia), speech deficits, and full-body seizures. If seizures start in middle age or later, SOL is a possible diagnosis to consider.

Diagnosis

Diagnosing SOL requires a thorough interview (anamnesis) about the symptoms, their duration, and the patient's medical history. Doctors will also perform a physical examination related to the patient's complaints, as well as neurological exams like brain strength tests, hearing or vision tests, and facial nerve tests. Additional tests to help confirm the diagnosis and rule out differential diagnoses include CT scans, PET scans, or MRI.

Management

Early treatment of SOL is crucial to facilitate management. If not treated promptly, the condition can worsen over time. In cases of malignancy, primary brain tumors typically do not spread and remain in one place, but brain tumors can exert pressure and damage surrounding areas. Treatment depends on factors like the tumor's size, type, and location.

Main treatments for brain tumors include radiotherapy, chemotherapy, or surgery. Radiation therapy uses high-energy rays to kill tumor cells. Side effects of radiation therapy may include fatigue, headaches, memory loss, and scalp irritation.

Chemotherapy uses drugs to kill cancer cells. Chemotherapy drugs can be taken orally or injected. The most commonly used chemotherapy drug for brain tumors is temozolomide. Common side effects of chemotherapy include nausea, vomiting, and hair loss.

Radiosurgery involves targeting tumor cells with radiation beams to kill them in a small area. If the brain tumor's location allows for surgery, doctors will remove as much of the tumor as possible. Risks of brain tumor surgery include infection and bleeding.

Other treatments can relieve symptoms, such as medications to reduce increased intracranial pressure, antiepileptic drugs, pain relievers, and anti-nausea medications.

Complications

Complications from SOL can include weight loss, back pain, or headaches, abdominal swelling, breathing difficulties, and abnormal facial and head shapes. Brain tumor complications can rapidly worsen and become life-threatening. Brain tumors can cause bleeding, increasing brain pressure. In some cases, brain tumors can push other brain parts into the spinal cord due to increased pressure, called herniation. Herniation signs include rapid breathing and body rigidity. This condition is extremely dangerous and life-threatening.

Prevention

Regular comprehensive health check-ups at nearby health facilities every year are recommended for early detection. Additionally, adopting a healthy lifestyle, reducing or quitting smoking, avoiding radiation exposure, and reducing the intake of preserved foods and artificial sweeteners can help prevent brain tumors.

When to see a doctor?

It is advised to see a doctor immediately if you experience any symptoms mentioned above. Seeking medical attention early before symptoms worsen and cause complications is crucial for quick treatment.