Monarch Disease Ontology identifier MONDO_0006145 (chondroid chordoma) is a slow-growing malignant bone tumor arising from the remnants of the notochord and occurring in the base of the skull. The tumor is characterized by a lobulated growth pattern, myxoid stroma formation, and the presence of physaliphorous cells and cartilage. Also known as: chondroid chordoma (morphologic abnormality).