原發性顱內骨肉瘤（Primary intracranial osteodarcoma, PIOS)是一個臨床上非常罕見的疾 病，僅少數病例曾經在文獻中被報告。由於其罕見性，對於其根治性治療方式、輔助治療之角 色、以及治療後追蹤的方式並沒有一定的標準。我們在此報告一位59歲女性之PIOS病患，其初始治療包括了根除性手術，以及術後60 Gy之原發部位的輔助放射治療。治療後其局部控制效果良好並無局部復發現象，但在手術4個月後卻在顱內發生異時性非局部復發。復發後我們再次安排根除性手術並輔以輔助性放射治療。由我們的經驗看來，根除性手術並輔以局部補助性放射治療是一個對於PIOS有效的局部控制治療模式，但對於此疾病之病患，須注意其非局部異時性顱內復發之可能。

Primary intracranial osteosarcoma (PIOS) is a rare intracranial malignancy, only a few case reports have been published in the literature. The curative treatment, the role of adjuvant treatment, and follow-up protocol is not well standardized due to its rarity. We present a 59-year-old woman with PIOS treated with radical surgery followed by adjuvant radiotherapy (RT) to the tumor bed for 60 Gy. Good local control was achieved but she experienced metachronous recurrence 4 months after the initial surgery. A second course of treatment was carried out for her recurrence tumor as radical surgical removal and second course adjuvant RT. The treatment including radical surgery and adjuvant RT seems to be effective for local control but cautions should be taken for possible aggressive metachronous recurrence.