A pinealoma, also called a pineal tumor, is a rare tumor of the pineal gland in your brain. The pineal gland is a tiny organ near the center of your brain that secretes certain hormones, including melatonin. It’s involved in regulating the body’s biological rhythms.

Pinealomas are more common in children than adults. They account for 3 to 11 percent of brain tumors in children and less than 1 percent of brain tumors in adults.

Pineal tumors can be both benign (noncancerous) and malignant (cancerous). They’re given a grade between 1 and 4 based on how fast they grow, with 1 being the slowest growing grade and 4 being the most aggressive.

The are several types of pinealomas, including:

  • pineocytoma: a grade I, benign, slow-growing tumor
  • pineal parenchymal or papillary tumor: grade II and grade III tumors, which are more likely to come back after they’re removed
  • pineoblastoma: a grade IV cancerous tumor that’s fast-growing and likely to spread to nearby tissues
  • mixed pineal tumor: contains different cell types

The symptoms of pineal tumors depend on the size, location, and type of tumor. Smaller tumors often don’t cause any symptoms. As they grow, tumors can press against nearby structures, leading to increased skull pressure.

Symptoms of a larger pinealoma include:

Precocious puberty

Pinealomas can disrupt children’s endocrine systems, which control hormones. When this happens, children can go through precocious puberty. This is when girls begin puberty before the age of 8 and boys before the age of 9.

Symptoms of precocious puberty include:

  • breast growth in girls
  • testes growth in boys
  • rapid increase in height
  • changes in body size and shape
  • pubic or underarm hair
  • changes in body odor

In addition, girls may have their first menstrual cycle. Boys may notice facial hair and changes in their voice.

Researchers aren’t sure what causes pinealomas. But mutations to the RB1 and DICER1 genes can increase someone’s risk of developing a pineoblastoma. Mutations are inherited from parents, which suggests pinealomas may be at least partly genetic.

Other potential risk factors include exposure to radiation and certain chemicals.

To diagnose a pinealoma, your doctor will review your symptoms and ask questions about when they started. They’ll also review your medical history and ask whether you know of any family members with pinealomas.

Based on your symptoms, your doctor may give you a neurological exam to check your reflexes and motor skills. You might be asked to complete a few simple tasks for the exam. This will give them a better idea of whether something’s putting extra pressure on part of your brain.

If your doctor thinks you might have a pineal tumor, they’ll likely do some additional testing to figure out what kind it is, including:

  • Visual field exam: This exam checks your central and peripheral vision. Your doctor will also check your eyes for swelling of the optic nerve, which can be a sign of increased pressure in your skull.
  • Imaging scans: Head MRI and CT scans can give your doctor a detailed view of your pineal gland. They’ll also help your doctor determine the location, shape, and size of a tumor.
  • Biopsy: A biopsy entails taking a tissue sample from the tumor to determine the type and grade. This will also help to determine whether it’s benign or malignant.
  • Lumbar puncture: For this test, a needle is inserted into the spinal cord to collect a sample of cerebral spinal fluid (CSF) to be examined for tumor cells.
  • Blood tests: Your blood may be drawn to check for certain hormones and substances released into the blood by organs, tissues, or tumor cells. Unusual levels may be signs of disease, including a pineal tumor.

The treatment for a pineal tumor varies depending on several factors, including:

  • whether it’s benign or malignant
  • its size and location
  • whether it’s spread
  • if it’s new or has come back after treatment

Radiation is the standard treatment for most types of pineal tumors.

Benign tumors

Benign pineal tumors may be surgically removed. If your pineal tumor has caused a buildup of fluid causing intracranial pressure, you may need to have a shunt, a thin tube implanted to drain excess cerebral spinal fluid (CSF).

Malignant tumors

Surgery can also remove or decrease the size of cancerous pinealomas. You may also need radiation of the entire brain and spinal cord, especially if your doctor can remove only part of the tumor. If the cancer cells have spread or the tumor is rapidly growing, you may also need chemotherapy in addition to radiation treatment.

Following treatment, you’ll need to regularly follow up with your doctor for imaging scans to ensure the tumor doesn’t return.

If you have a pinealoma, your prognosis depends on the type of tumor and how large it is. Most people fully recover from benign pinealomas and even many types of malignant ones. But if the tumor grows quickly or spreads to other body parts, you may face additional challenges.

The relative 5-year survival rate for all types of pineal tumors is 69.5 percent. An individual’s survival rate depends on many factors, including a person’s age and health and their response to treatment.

Your doctor can give you more specific information about what to expect based on your unique situation.