secondary neoplasm metastatic neoplasm metastatic disease A tumor that has spread from its original (primary) site of growth to another site, close to or distant from the primary site. Metastasis is characteristic of advanced malignancies, but in rare instances can be seen in neoplasms lacking malignant morphology. NCIT:C3261 metastatic tumor UMLS:C2939420 MEDGEN:422476 EFO:0009709 MONDO:0024883 ICDO:8000/6 metastatic neoplasm metastatic tumour obsolete_metastatic neoplasm