1) A benign neoplasm derived from connective tissue, consisting chiefly of polyhedral and stellate cells that are loosely embedded in a soft mucoid matrix, thereby resembling primitive mesenchymal tissue. It occurs frequently intramuscularly where it may be mistaken for a sarcoma. It appears also in the jaws and the skin. (From Stedman, 25th ed)

2) A benign soft tissue neoplasm characterized by the presence of spindle and stellate cells, lobulated growth pattern, and myxoid stroma formation.

3) A benign soft tissue neoplasm characterized by the presence of neoplastic spindle and stellate cells in a myxoid stroma.