Diagnostic exam results for case 3. Chest enhanced CT (A) and T2-weighted MRI (B) showed a well-defined and ovoid mass located in the paravertebral sulcus. The tumor extended into the spinal canal. Six months after initial detection of the tumor, chest enhanced CT (C) showed a huge, heterogeneous mass extending into the intraspinal canal with involvement of adjacent vertebrae. The microscopic appearance of the tumor is shown (D). The tumor was a highly cellular malignant spindle cell neoplasm that contained alternating cellular and more myxoid areas (low-power view). The tumor cells had eosinophilic cytoplasm, wavy hyperchromatic nuclei, and high mitotic activity (high-power view).