Monarch Disease Ontology term MONDO_0006232 (giant cell tumor of soft tissue) is a painless, well circumscribed tumor arising in soft tissue, usually of the upper and lower extremities. Morphologically, it is characterized by a multinodular growth pattern. The cellular infiltrate is composed of mononuclear round or oval cells and multinucleated osteoclast-like giant cells, in a rich vascular stroma. It rarely metastasizes. Also known as: GCT-ST, Osteoclastoma of soft tissue.