Monarch Disease Ontology id MONDO_0002528 (synovium neoplasm) is a benign or malignant soft tissue neoplasm arising exclusively from the synovial membrane. Examples include the diffuse giant cell tumor of tendon sheath, localized giant cell tumor of tendon sheath, and malignant giant cell tumor of tendon sheath. Also known as: neoplasm of synovial membrane of synovial joint, neoplasm of synovium, neoplasm of the synovium, synovial membrane of synovial joint neoplasm, synovial membrane of synovial joint neoplasm (disease), synovial membrane of synovial joint tumor, synovial membrane of synovial joint tumour, synovial neoplasm.