一位60歲女性病人於二年前健康檢查中發現一右腎腫瘤，然病人並未積極處理。該腫瘤在近日門診追蹤時出現變大的情況，電腦斷層顯示右腎門區域有一1.5x2.0公分腫瘤。在懷疑腎細胞癌下執行右側根除性腎全切除術；病理診斷為一罕見源自腎包膜的平滑肌瘤，特提出來報告，並作文獻上的回顧。

A 60-yr-old female patient was a victim of right renal tumor disclosed in January 1996. Recently, an increased size of the tumor mass was noted during OPD ultrasonographic follow up. Computed tomography revealed a mass 1.5 x 2.0 cm occupying the right middle pole near the hilar region. Under the suspicion of renal cell carcinoma, she was treated with radical nephrectomy. The histology of the tumor showed a picture of leiomyoma arising from the renal capsule. We present this case and review the literature.