Monarch Disease Ontology term MONDO_0005462 (primitive neuroectodermal tumor) is a malignant neoplasm that originates in the neuroectoderm. The neuroectoderm constitutes the portion of the ectoderm of the early embryo that gives rise to the central and peripheral nervous systems and includes some glial cell precursors. Also known as: PNET, neuroectodermal neoplasm, neuroectodermal tumor, neuroectodermal tumour, primitive neuroectodermal neoplasm, primitive neuroectodermal tumor (PNET), primitive neuroectodermal tumour (PNET).