A malignant neoplasm arising exclusively from the soft tissues. The disease is malignant soft tissue neoplasm (Monarch Disease Ontology term MONDO_0024637). Also known as: malignant neoplasm of soft tissue, malignant neoplasm of the soft tissue, malignant soft tissue tumor, malignant soft tissue tumour, malignant tumor of soft tissue, malignant tumor of the soft tissue, malignant tumour of soft tissue, malignant tumour of the soft tissue.