Infantile suprasellar tumor diagnosed as a pineoblastoma RB1 subgroup and treatment challenges: A pediatric SNO Molecular Tumor Board

Pineoblastomas are rare CNS embryonal tumors, accounting for 30% of pineal tumors, and often affecting infants and young children. 1–3 Historically, tumors were grouped with supratentorial primitive neuroectodermal tumors and treated on high-risk brain tumor protocols with intensive multimodality treatments, often including craniospinal irradiation (CSI). 2 Four distinct molecular subgroups of pineoblastoma have recently been identified (PB-miRNA1, PB-miRNA2, PB-MYC/FOXR2, and PB-RB1). 1,3 PB-miRNA1 and PB-miRNA2 affect older children (median 8.5-11.8 years) while PB-RB1 and PB-MYC/FOXR2 affect younger children (median 1.4-2.1 years). Patients <3 years old have a 5-year overall survival (OS) of 24.2% compared with 77.0% in older children. 1,2 We present a diagnostically challenging case of an infant with a suprasellar tumor found to be a pineoblastoma, PB-RB1 subgroup. This case illustrates challenges in treating PB-RB1, which harbor a poor prognosis and limited radiation options due to pa-tients’ young age. We discuss strategies to limit treatment-related toxicities while improving outcomes for young children with PB-RB1. throughput genetic and epigenetic studies identified increased expression in epidermal growth factor receptors (EGFR) in the RB subgroup of pineoblastoma. Endersby demonstrated the erythro-blastic leukemia viral oncogene homolog inhibitor (pan-ERBB inhibitor) Dacomitinib inhibited EGFR signaling in in vitro models of pineoblastoma and had efficacy in orthotopic models of pediatric brain Many EGFR inhibitors have been tested in children. We treated our patient with Gefitinib given the extensive safety data in pediatric patients and efficacy in treating pediatric brain tumors. Newer agents like lapatinib EGFR signaling require further clinical