Primary smooth muscle tumor of kidney:a clinicopathological study of 4 cases

Objective To study the clinicopathological characteristics,etiology and differential diagnosis of primary smooth muscle tumor of the kidney by presenting four new cases and a review of literature.Methods Two cases of leiomyoma and two cases of leiomyosarcoma were studied by routine HE,immunohistochemical staining,together with review of the literature.Results Four cases of renal smooth muscle tumor showed the characteristics of smooth muscle cells by HE and immunohistochemical staining,the leiomyoma of the kidney had a moderate feature,and the leiomyosarcoma was of malignant behaviors.Follow-up showed that postoperative survival of two renal leiomyoma cases were good;one case of renal leiomyosarcoma had a recurrence,and 1 case was missed.Conclusion Primary smooth muscle tumor of the kidney is rare,which requires a combination of clinical,histological and immunohistochemical features to make differential diagnosis from other benign and malignant tumors of the kidney.The prognosis of the leiomyoma is good,but leiomyosarcoma has a poor prognosis.