The patient went on to have CT guided core biopsies of the lesion 

Histology

Microscopic Description: Sections show several core biopsies involved by malignant spindle cell neoplasm. The tumor cells are arranged in a vaguely fascicular pattern. Mitotic figures are easily identified. A subendothelial infiltrative arrangement of tumor cells is evident in some areas. 

Final Diagnosis:  malignant peripheral nerve sheath tumor