Pineoblastomas

ALSO KNOWN AS: Pinealoblastomas

RELATED CONDITIONS: Supratentorial primitive neuroectodermal tumors, pineocytomas

DEFINITION: Pineoblastomas, made up of immature cells in the pineal gland (a small organ near the center of the brain), are fast-growing, cancerous tumors that primarily affect young children and people between twenty and forty years of age. The pineal gland is made up of two main cell types: glial cells, which give it its form, and pinealocytes, neural cells with photosensory and neuroendocrine functions that produce several hormones, including melatonin, which helps to control the sleep-wake cycle. Pineoblastomas are invasive tumors that spread to nearby areas of the brain and cerebrospinal fluid and can cause bleeding into the brain’s ventricles. Pineoblastomas should not be confused with pineocytomas, slow-growing, benign tumors that primarily develop in middle-aged and older adults.

Risk factors: The risk factors for pineoblastoma are unknown; however, some researchers believe gene mutations may be involved.

Etiology and the disease process: The cause of pineoblastomas is unknown, but it is believed to be related to gene abnormalities. Researchers studying other diseases have noticed an increased incidence of pineoblastoma in patients with hereditary, bilateral retinoblastoma caused by the retinoblastoma gene (RB1). They believe this gene may play a role in the development of pineoblastoma and affect its response to treatment. However, because of the rarity of pineoblastoma, research is limited, and this theory needs to be investigated sufficiently.

As pineoblastomas grow, they cause increased pressure in the brain and block the flow of cerebrospinal fluid, causing many neurologic symptoms. Because cells in the pineal gland produce hormones needed for normal body functions, pineoblastomas also cause changes in other body systems. In a process called seeding, they tend to produce multiple, initially small, tumors that are deposited into the cerebrospinal fluid early in the disease process. Pineoblastomas then spread through the brain and spinal cord via the cerebrospinal fluid. When they spread to other body areas, the most common sites are the bones and lungs.

Incidence: Brain tumors are the second most common type of childhood cancer. However, pineoblastomas are extremely rare among these brain tumors, with only about 0.2 percent incidence out of all brain tumors. Each year, cancer of the brain and spinal cord occurs in about 4,000 children younger than age fifteen in the United States. Of that number, less than fifty will be diagnosed with pineoblastoma.

Symptoms: Pineoblastomas cause symptoms related to an increase in pressure inside the brain and blockage of cerebrospinal fluid. They can vary depending on the size of the tumor, its location, and the child’s age. Most symptoms of pineoblastomas are similar to those of other brain tumors, including nausea and vomiting, seizures, changes in personality or behavior, unusual sleepiness, headaches, double vision, and developmental delays or failure to thrive. Hydrocephalus, an excessive accumulation of fluid in the brain, and hormonal abnormalities may also occur.

Screening and diagnosis: Screening for abnormal brain function takes place whenever a medical practitioner makes a physical examination of a child and takes a growth and development history. When abnormalities appear, the practitioner will typically order laboratory tests and possibly imaging studies. Laboratory tests usually include a complete blood count, electrolyte levels, and liver, thyroid, and kidney function tests. Imaging studies include a chest X-ray, bone scan, magnetic resonance imaging (MRI), and computed tomography (CT) scanning. An examination of the cerebrospinal fluid, called a lumbar puncture, will be performed to look for cancer cells as well as to rule out other diseases. If the child’s condition permits, a definitive diagnosis of pineoblastoma is made during surgery, after a pathologist examines the tumor cells.

For pineoblastoma, the extent of the cancer is usually described as risk groups instead of stages. The tumor is called “average risk” when the child is older than age three, most or all of the tumor was removed by surgery, and the cancer has not spread beyond the pineal gland. It is called “poor risk” when the child is younger than age three, the tumor was near the center of the brain, some of the tumor was not removed by surgery, or the cancer has spread to other parts of the brain or body, including the spinal cord.

Treatment and therapy: Treatment for pineoblastoma is based on the child’s age and risk group. When the child is younger than age three, surgical removal of most or all of the tumor is performed. Microsurgical techniques have been developed that can better target the tumor, leaving healthy tissue intact. Stereotactic radiosurgery is an additional surgical method undergoing clinical trials, which may increase positive prognosis and lessen the side effects of treatment. If the child is considered a poor risk, chemotherapy is used after surgery. When the child is older than age three, surgery is followed by radiation treatment of the entire brain and spinal cord. Any child considered a poor risk might also be given chemotherapy. In the twenty-first century, doctors have discovered genetic and molecular differences in pineoblastomas in children and adults. This discovery has led to more targeted treatments based on the patient.

Prognosis, prevention, and outcomes: There is no known prevention for pineoblastoma. The prognosis for pineoblastomas varies with the child’s age and risk group, but it is typically poor, with an estimated survival time of sixteen to twenty-five months. Although some children do survive five years or more, the tumors commonly recur or develop in other parts of the body. When they do, they are almost always fatal. The five-year survival rate is between 60 and 70 percent, but it is much less when the child is younger than five years old. The survival rate is also dependent on the age of the patient, the severity of the tumor, and the treatment used.

Bibliography

Amendola, B. E., et al. “Pineal Tumors: Analysis of Treatment Results in Twenty Patients.” Journal of Neurosurgery, vol. 102, 2005, pp. 175–79.

Bruce, J. N., and A. T. Ogden. “Surgical Strategies for Treating Patients with Pineal Region Tumors.” Journal of Neurooncology, vol. 69.1–3, 2004, pp. 221–36.

“Cancer in Children and Adolescents.” National Cancer Institute, 27 Sept. 2023, www.cancer.gov/types/childhood-cancers/child-adolescent-cancers-fact-sheet. Accessed 25 June 2024.

Grisham, Julie. “Research Advances the Genetic Understanding of Pineoblastoma, a Rare Brain Cancer.” Memorial Sloan Kettering Cancer Center, 20 July 2018, www.mskcc.org/news/new-research-advances-genetic-understanding-pineoblastoma-rare-brain. Accessed 25 June 2024.

Gururangan, S., et al. “High-Dose Chemotherapy with Autologous Stem-Cell Rescue in Children and Adults with Newly Diagnosed Pineoblastomas.” Journal of Clinical Oncology, vol. 21.11, 2003, pp. 2187–191.

Hansford, Jordan R., et al. "Pediatric Pineoblastoma: A Pooled Outcome Study of North American and Australian Therapeutic Data." Neuro-oncology Advances, vol. 4, no. 1, 2022, doi.org/10.1093/noajnl/vdac056. Accessed 25 June 2024.

“Key Statistics for Brain and Spinal Cord Tumors in Children.” American Cancer Society, 12 Jan. 2023, www.cancer.org/cancer/types/brain-spinal-cord-tumors-children/about/key-statistics.html. Accessed 25 June 2024.

Lacruz, César R., Javier Saénz de Santamaría, and Ricardo H. Bardales. Central Nervous System Intraoperative Cytopathology. New York: Springer, 2014.

Nandoliya, Khizar R., et al. "Post-Surgical Prognosis of Patients with Pineoblastoma: A Systematic Review and Individual Patient Data Analysis with Trends over Time." Cancers, vol. 15, no. 13, 2023, doi.org/10.3390/cancers15133374. Accessed 25 June 2024.

“Pineoblastoma.” St. Jude Children's Research Hospital, www.stjude.org/disease/pineoblastoma.html. Accessed 25 June 2024.

Raghavan, Derek, et al. Textbook of Uncommon Cancer. 4th ed., Chichester: Wiley, 2012.

Yachnis, Anthony, and Maria Rivera-Zengotita. Neuropathology. Philadelphia: Elsevier, 2014.