[Two autopsied cases of radiation-induced gliosarcoma].

Two autopsied cases of radiation induced gliosarcoma are presented in detail with a review of the literatures. Case 1 was that of a 36-year-old female who was found to have a metastatic choriocarcinoma in the right occipital lobe and received radiation therapy of 45 Gy. Four years later CT scan showed a new enhanced tumor in the cerebellum within the previously irradiated field. Total removal was performed and histological diagnosis of the tumor was a gliosarcoma. She died 12 months after the operation. Case 2 was that of a 63-year-old male who had a protoplasmic astrocytoma in the left temporal lobe and received radiation therapy of 60 Gy after surgery. The tumor recurred in the left temporal base after 9 years. Histological finding of the surgical specimens showed gliosarcoma. The patient died 2 months after he was operated on. The tumors had obviously two defined neoplastic components. One was gliomatous features with anaplastic glial cells which stained for glial fibrillary acidic protein. The other was malignant mesenchymal features with spindle shaped fibrosarcoma cells which contained numerous reticulin fibers. Postmortem examination revealed these similar features. Criteria for identifying a tumor as a radiation induced neoplasm have been proposed by Fajado. The main criterion is that the induced tumor should occur in the previously irradiated field. Secondly, it should appear after a latent period. Thirdly, the pathology should be different from the initial neoplasm. Our cases fulfil these criteria.(ABSTRACT TRUNCATED AT 250 WORDS)