Leiomyosarcoma of the kidney: a clinicopathologic study.

Leiomyosarcoma of kidney is a rare lesion for which limited data are available. Cases coded as leiomyosarcoma of the kidney from three institutions were reviewed. These cases comprised 3 men and 7 women, 40 to 75 years of age. Immunohistochemistry was performed where possible and clinical follow-up information was obtained. On immunohistochemical staining, 6 of 6 tumors expressed smooth muscle actin, desmin, calponin, and h-caldesmon, and epithelial membrane antigen was positive in 1 of 5. Tumors were negative for cytokeratin and S-100 protein. Follow-up information was available for 9 patients. Two patients had metastases at diagnosis, four developed metastases, and two had recurrent disease. Five of 9 died of disease. Two patients were alive with no evidence of disease after 19 and 60 months, and 2 patients were alive with disease after 48 months and 56 months. Comparing outcome with tumor grade, the one patient with grade 1 tumor was alive with no evidence of disease; of 5 patients with grade 2 tumor, 2 died of disease, 1 was alive with no evidence of disease, 1 was alive with disease, and 1 was alive with extensive disease; all 3 grade 3 patients died of disease. In summary, the majority of renal leiomyosarcomas are intermediate or high grade with correspondingly poor prognosis.