Central nervous system (CNS) tumors are the most common solid malignancies among children. Although some types of CNS tumors like medulloblastomas and low-grade gliomas are widespread and well-studied, there is a huge number of rare diseases that need further research. This international registry aims to establish a large multicenter database of pediatric and young adult patients with rare embryonal tumors of the central nervous system and describe the clinical presentations, diagnostics, treatment regimens, and outcomes. Embryonal tumors with multilayered rosettes (ETMR), FOXR2-activated CNS neuroblastoma, cribriform neuroepithelial tumor, and CNS tumor with BCOR internal tandem duplication are extremely rare embryonal tumors some of which were first described in the last edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System. Objectives of the registry are 1) to evaluate prognostic factors, 2) to identify diagnostic and treatment gaps, 3) to investigate the characteristics and outcome of the disease with different treatment regimens, and 4) to generate data-based prospective diagnostic and treatment recommendations.