A pinealoma, sometimes called a pineal tumor, is a rare tumor of the pineal gland in your brain. The pineal gland is a tiny organ located near the center of your brain that secretes certain hormones, including melatonin. Pinealomas account for only 0.5 to 1.6 percent of brain tumors.

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 one being the slowest growing grade, and 4 being the most aggressive.

The are several types of pinealomas, including:

  • pineocytomas
  • pineal parenchymal tumors
  • pineoblastomas
  • mixed pineal tumors

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

Symptoms of a larger pinealoma include:

  • headaches
  • nausea
  • vomiting
  • vision problems
  • feeling tired
  • irritability
  • trouble with eye movements
  • balance issues
  • difficulty walking
  • tremors

Precocious puberty

Pinealomas can disrupt children’s endocrine systems, which control hormones, triggering something called precocious puberty. This condition causes girls to start going through puberty before the age of eight, and boys before the age of nine.

Symptoms of precocious puberty in both girls and boys include:

  • rapid growth
  • changes in body size and shape
  • pubic or underarm hair
  • acne
  • changes in body odor

In addition, girls may have breast growth and their first menstrual cycle. Boys may notice enlargement of their penis and testicles, facial hair, and changes in their voice.

Researchers aren’t sure what causes pinealomas. However, mutations to the RB1 gene can increase someone’s risk of developing a pineoblastoma. This mutation is inherited from a parent, 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 start by reviewing your symptoms and asking questions about when they started. They’ll also review your medical history and ask if 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 as part of 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 some kind of 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 scans and CT scans can give your doctor a detailed view of your pineal gland. They’ll also help your doctor determine location, shape, and size of a tumor.
  • Biopsy. A biopsy entails taking a sample of tissue from the tumor to determine the type and grade of the tumor. 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. Blood tests may be used to check the levels of certain hormones and proteins, such as melatonin. If any of these levels are unusual, there may be a problem with your pineal gland, including a tumor.

The treatment for pineal tumors varies depending on whether they’re benign or malignant as well as their size and location.

Benign tumors

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

Malignant tumors

Surgery can also remove or decrease the size of malignant pinealomas. You may also need radiation treatment, especially if your doctor can only remove part of the tumor. If the cancer cells have spread or the tumor is rapidly growing, you may also need chemotherapy on top of radiation treatment.

Following treatment, you’ll need to regularly follow-up with your doctor for imaging scans to make sure 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 make a full recovery from benign pinealomas, and even many types of malignant ones. However, if the tumor grows quickly or spreads to other body parts, you may face additional challenges. Your doctor can give you more specific information about what to expect based on the type, size, and behavior of your tumor.