Trilateral retinoblastoma (TRB) occurs in 3% of patients with unilateral or bilateral germline retinoblastoma.1 This midline malignant neuroectodermal tumor arises commonly in the pineal gland (77%-83% of patients) and less frequently in the parasellar region (17%-23% of patients).2,3
Trilateral retinoblastoma is difficult to treat and usually fatal.3 Complete resection is seldom possible for tumors in the pineal or parasellar locations.4 Craniospinal irradiation is too damaging to the growth, intellectual, cognitive, and endocrine functions, particularly for children younger than 3 years of age.5-7 Chemotherapy alone rarely cures young children with other intracranial neuroectodermal tumors, such as medulloblastoma.8 Trilateral retinoblastoma often presents with dissemination in the cerebrospinal fluid (CSF) (leptomeningeal TRB or neoplastic meningitis) and is extremely difficult to cure because most intrathecal drugs are ineffective for solid-tumor CSF metastases.9