Pinealoblastoma may occur in patients with hereditary uni- or bilateral retinoblastoma. When retinoblastoma patients present with pinealoblastoma this is characterized as "trilateral retinoblastoma". Up to 5% of patients with hereditary retinoblastoma are at risk of developing trilateral retinoblastoma. Prognosis of patients with trilateral retinoblastoma is dismal, only a few patients have survived more than 5 years after diagnosis; all survivors were diagnosed with small tumors in a subclinical stage. Recent advances in (high-dose) chemotherapy treatment regimens and early detection have improved survival of patients with trilateral retinoblastoma to up to 50%.
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^de Jong MC, Kors WA, de Graaf P, Castelijns JA, Kivelä T, Moll AC (September 2014). "Trilateral retinoblastoma: a systematic review and meta-analysis". The Lancet. Oncology. 15 (10): 1157–67. doi:10.1016/s1470-2045(14)70336-5. PMID25126964.