Grossly, the fairly well-circumscribed, vaguely lobulated, fusiform tumor measured 6.0 cm in greatest diameter and consisted of soft to firm, tan-white tissue with a focally gelatinous cut surface. Focal areas of cystic hemorrhage were present (Figure 2). Microscopically, the tumor was composed of strands of epithelioid to spindle-shaped cells with uniform, round to oval, hyperchromatic nuclei and variably clear to eosinophilic cytoplasm embedded in a fibromyxoid matrix. Densely cellular areas were separated by thick bands of fibrous stroma, and loosely cellular clusters of cells were embedded in a more abundant myxoid matrix (Figure 3) that was reactive with Alcian blue (pH 2.5) in the presence or absence of hyaluronidase. Well-differentiated hyaline cartilage was not identified. The mitotic activity was generally low. No necrosis was observed. The tumor cells were reactive immunohistochemically with vimentin and epithelial membrane antigen in a focal pattern. Results of staining for S100 protein and cytokeratins were negative.