Pineoblastoma

Pineoblastomas typically occur at very young ages. One study found the average age of presentation to be 4.3 years, with peaks at age 3 and 8. Rates of occurrence for males and females are similar, but may be slightly more common in females. This difference was most apparent in patients aged 5 to 9 years old. == Pathophysiology ==

The pineal gland is a small organ in the center of the brain that is responsible for controlling melatonin secretion. Due to the pineal gland's location at the center of the brain and the rapidly growing nature of this disease, obstruction of CNS fluid is a common symptom. The exact cause of pineoblastoma is unknown. MicroRNA dysregulation has been found to be associated with many cases of pineoblastoma, specifically, mutations in DICER1 and DROSHA genes. DICER1 germline mutations cause a tumor predisposition syndrome, and should be considered in patients with pineoblastoma. Pineoblastoma may occur in patients with hereditary uni- or bilateral retinoblastoma. When retinoblastoma patients present with pineoblastoma this is characterized as "trilateral retinoblastoma". Up to 5% of patients with hereditary retinoblastoma are at risk of developing trilateral retinoblastoma. This tumor combination is more aggressive than an isolated pineoblastoma. Recent advances in (high-dose) chemotherapy treatment regimens and early detection have improved survival of patients with trilateral retinoblastoma to up to 50%. Additionally, various mutations or deletions in chromosomes 1, 9, 13, 16 and 22 have been associated with pineoblastoma incidence. == Clinical features ==

The most common symptoms to occur with pineoblastoma are headache, behavior changes, and cognitive disturbances. These masses also often cause obstructive hydrocephalus, leading to increased intracranial pressure. This can result in vision changes and Parinaud's syndrome. Pineoblastomas often invades locally, with spread to the head and spine seen in 25–41% of patients. == Diagnosis ==

Several imaging methods can be used to diagnose pineoblastoma. Initially, urgent CTs are recommended, followed by MR imaging. == Treatment ==

Initial treatment for pineoblastoma often includes a shunting procedure to redirect accumulated cerebrospinal fluid secondary to obstructive hydrocephalus. This shunt can help manage increased intracranial pressure and relieve some symptoms. Surgery to remove the tumor is associated with better outcomes, however, this is not always possible due to the proximity of the pineal gland to neurovascular structures. Complete tumor resection is only seen in about 30% of cases. Following surgery, radiation therapy to the brain and spinal cord can increase survival. However, radiation can only safely be used in patients over 3 years old due to the risk of significant neurological impairment. Chemotherapy treatment can also be used, either before or after surgery; its optimal use is still under investigation. == Prognosis ==

Pineoblastomas are very aggressive tumors. 5-year survival for patients with pineoblastomas is around 58%. Prognosis for patients under 5 years old is lower, between 15 and 40%. Disseminated disease at diagnosis is also associated with worse outcomes. When pineoblastomas occur with retinoblastomas, the prognosis is typically worse, and these patients require more aggressive treatment. When stratified by molecular subtype, localized, microRNA-altered pineoblastomas are in contrast associated with superior outcome when treated with radiation and chemotherapy. Complete gross tumor resection is associated with improved prognosis, but is difficult and rare to achieve. Radiation therapy after surgery is also linked to improved survival. == References ==