Error parsing node of kind 'ERROR': {Node ERROR (0, 171) - (0, 338)} disease_tree?object=eq."An osteosarcoma that is an usually aggressive malignant bone-forming mesenchymal neoplasm arising from the bone. It may arise de novo or from a pre-existing lesion of the bone. Pain and a palpable mass are the most frequent clinical sign and symptom. It may spread to other anatomic sites, particularly the lungs." Err("Unexpected Node kind: ERROR")