Pineal Tumors - Causes, Symptoms, Diagnosis, and Treatment

What Is the Pineal Gland?

The pineal gland is an endocrine gland that is located in the diencephalic( a division of the forebrain) area of the brain above the hypothalamus. It is also referred to as “Epiphysis cerebri” and “conarium.” It is a pea-sized gland with a weight of around 170mg. The main function of the pineal gland is that it secretes “melatonin” hormone in the body. Its other functions include regulating the sleep cycle, female hormonal imbalance, etc.

What Are Pineal Tumors?

Tumors that develop in the pineal gland are referred to as pineal tumors. They are tumors of the primary central nervous system. Its development starts in the brain (pineal gland), and it can spread to involve the spinal cord also. Pineal tumors affect the function of the pineal gland and cause symptoms like insomnia, headache, etc. some of the types of pineal gland tumors include:

True Pineal Tumors:

1. Pineocytoma (slow-growing and is a grade 2 tumor).

2. Pineoblastoma (aggressive grade 4 tumor with malignant characteristics).

3. Pineal parenchymal tumor and papillary pineal tumor ( intermediate grade 2 or 3 tumors).

Mixed Pineal Tumors:

It consists of both slow-growing and fast-growing cell types.

Some of the tumors are not necessarily pineal tumors, but they do occur in this region. Such tumors include:

1. Germinoma (a tumor that begins in germinal cells).

2. Meningioma (tumors that arise from membranes surrounding the brain and spinal cord).

3. Astrocytoma (cancer that occurs in the brain or spinal cord).

4. Dermoid cysts (a cyst that occurs in skin containing hair, sebaceous glands, follicles, etc.).

5. Ganglioglioma (a rare brain tumor).

Who Is More Likely to Be Diagnosed With Pineal Tumors?

Pineal tumors are seen in both children and young adults. It is most commonly seen during the initial 20 years of life. It is more common in females. All types of pineal tumors have female predilection except papillary tumors of the pineal gland, which are more commonly seen in males.

What Causes Pineal Tumors?

The exact cause of pineal tumors is unknown. But certain risk factors increase the chance of developing pineal tumors that including:

• Gene mutation (RB1 gene).

• Exposure to radiation and chemicals.

What Are the Symptoms Seen in Pineal Tumors?

The symptoms of pineal tumors are often non-specific, and it is difficult to diagnose in the case of small pineal tumors as they produce less or no symptoms. Some of the common symptoms seen in pineal tumors are

• Headache.

• Nausea and vomiting.

• Disrupted sleep cycle.

• Tiredness and irritability.

• Finding it difficult to walk.

• Vision problems.

• Memory problems.

• Balance problems due to raised intracranial pressure that disrupts functions of the brain tissue.

Do Pineal Tumors Cause Any Life-Threatening Symptoms?

Pineal tumors cause raised intracranial pressure as a result of blockage of normal flow of CSF (cerebrospinal fluid). This results in a condition called hydrocephalus (fluid buildup in the brain). If it is untreated or not diagnosed early, then it becomes life-threatening.

How Do Pineal Tumors Cause Precocious Puberty?

Precocious puberty caused by pineal tumors is due to the hormonal imbalance that occurs due to the impaired function of the pineal gland. In precocious puberty, the child attains puberty at a much earlier age than normal. In precocious puberty, girls attain puberty at the age of 7 or 8, and in boys, it occurs at around 9 years of age. The symptoms of precocious puberty include:

• Change in body shape and size.

• Acne.

• Breast growth and early onset of menstruation in girls.

• Changes in voice and enlarged testicles, facial hair, and penis are seen in boys.

• Changes in body odor.

What Are the Different Grades of Pineal Tumors?

Pineal tumors are classified into four grades based on their characteristics. The grades are

1. Grade1: Grade 1 refers to slow-growing and low-grade tumors. For example, pineocytoma.

2. Grade 2 or 3: Grade 2 or 3 refers to intermediate-grade tumors of the pineal gland. In these grades, the chance of tumor recurrence is higher. Examples are pineal parenchymal tumors and papillary parenchymal tumors.

3. Grade4: This grade refers to the fast-growing malignant (cancerous) tumors. Metastasis (spread to other body parts) is seen in this stage. For examples, pineoblastoma.

How Are Pineal Tumors Diagnosed?

To diagnose pineal tumors, your doctor will ask you about your health and family history to delineate whether the condition is not associated with any genetic linkage. Your doctor will carry out a physical examination that includes testing your reflexes, muscle strength, etc. If your doctor finds any suspicious changes in your body related to pineal tumors, then he might suggest you have the following tests. That include:

• Blood Tests: Blood tests are asked to carry out to detect the presence of any tumor markers in the blood. The tumor markers in the blood include alpha-fetoprotein (AFP), and human choriogonadotropin (HCG) is seen in germ cell tumors. Levels of melatonin in the blood may also help in diagnosing pineal tumors.

• Lumbar Puncture (Spinal Tap): In a lumbar puncture, a small amount of CSF is collected by inserting a small needle into your spinal cord. Tumor cell presence is checked in the sample of CSF to detect the condition. Pineal tumors spread to the spinal cord could be detected through this test. It is often not preferred as it has an increased risk of herniation.

• Biopsy: Biopsy gives out a definitive diagnosis. It helps in finding the grade of the tumor based on the characteristic of the tumor.

• Imaging Tests: Imaging tests like MRI (magnetic resonance imaging) and CT (computed tomography) scans help in giving a detailed picture of the location, size, and spread of the tumor. These tests help in differentiating benign and malignant tumors of the pineal gland.

How Is Pineal Tumor Treated?

Pineal tumors are rare and often diagnosed later as it produces non-specific symptoms. Pineal tumors are best treated by neurosurgeons. A detailed consultation with a neurosurgeon is necessary. Pineal tumors can either be benign (non-cancerous) or malignant (non-cancerous). Grade 2 and 3 tumors show increased recurrence rates, whereas grade 4 tumors with high malignant potential, so such grades of the tumor, if detected, need a proper treatment plan suggested by the doctor to treat it better. Some of the common treatment options used are,

• Surgery: It is considered to be the first line of treatment for the pineal tumor. Surgery helps to remove the tumor completely and avoid its recurrence in the future. Surgical procedures are much more successful in treating benign tumors, whereas malignant pineal tumors require chemotherapy and radiation therapy followed by surgery.

• Chemotherapy: Chemotherapy uses drugs to kill cancer cells. It delivers good results when used as adjuvant therapy (chemotherapy followed by surgery). Your doctor will prescribe you the right chemotherapy drugs to treat pineal tumors.

• Radiation Therapy: Cancer cells are destroyed in radiation therapy using high-energy x-rays. However, radiation therapy in child pineal tumor patients is often risky as it causes radiation-induced effects in children, which affects the child's cognitive development.

• Endoscopic Third Ventriculostomy (EVT): EVT is a surgical procedure helpful in treating hydrocephalus. It is a safe procedure. It treats hydrocephalus by bypassing the obstructed CSF in the brain via an endoscope inserted into the skull through a bur hole and reduces the intracranial pressure.

Conclusion:

Pineal tumors are rare tumors affecting the pineal gland. It can be both benign and malignant. Malignant pineal tumors like pineoblastoma are difficult to treat, and the survival rate of pineoblastoma is low. But an early diagnosis of pineal tumors is highly valuable in treating the condition better as well as increasing the survival rate in malignant cases like pineoblastoma.