oligodendroglioma (MONDO_0016695, a Monarch Disease Ontology term) is a well-differentiated (WHO grade II), diffusely infiltrating neuroglial tumor, typically located in the cerebral hemispheres. It is composed predominantly of cells which morphologically resemble oligodendroglia. The neoplastic cells have rounded homogeneous nuclei and, on paraffin sections, a swollen, clear cytoplasm ('honeycomb' appearance). (Adapted from WHO). Also known as: WHO grade II oligodendroglial neoplasm, WHO grade II oligodendroglial tumor, WHO grade II oligodendroglial tumour, well differentiated oligodendroglial tumor, well differentiated oligodendroglial tumour, well differentiated oligodendroglioma.