Sacrococcygeal chordoma with a malignant spindle cell component. A report of two autopsy cases with a review of the literature.

Two autopsy cases of sacrococcygeal chordoma which showed sarcomatous components in the primary and metastatic tumors are reported. Case 1 was a 48-year-old female who died 9 years after the development of the initial symptoms. Autopsy findings showed metastatic tumors consisted of malignant tumor cells similar to fibrosarcoma and osteosarcoma. Case 2 was a 63-year-old male who died 11 years after the development of the initial symptom. At autopsy only sarcomatous tumors resembling malignant fibrous histiocytoma (MFH) were observed in the metastatic lesions. Both cases were treated with irradiation. It is suggested that the appearance of sarcomatous tumor in current two cases of chordoma might be due to the phenomenon of tumor progression closely associated with irradiation therapy. These two cases can be categorized as "chordoma with a malignant spindle cell component" in a sense that highly malignant sarcomatous components existed in conjunction with chordoma in the primary tumors.