Cystic leiomyosarcoma of the kidney: an unusual clinical presentation

Primary sarcomas of the kidney are rare, accounting for 1-3% of all renal malignancies. We describe an unusual case of renal leiomyosarcoma in a 41-year-old white woman who presented with a large smooth mass, which was mobile to the overlying structures and which occupied the right hypochondria and flank. Radical nephrectomy was carried out and the patient is well, without symptoms of relapse, 1 year after surgery. Leiomyosarcomas of the kidney have an aggressive and rapidly progressive natural history, with 5-year survival rates of 29-36%. Size <5 cm, low histological grade, absence of lymph node metastases and radical surgical treatment are all associated with a better prognosis. Irradiation and chemotherapy do not appear to alter the clinical course.