Solitary left ventricle metastasis by renal cell carcinoma with sarcomatoid features

A 64 year-old male presented with a mass of the left kidney, 9 cm across. A radical nephrectomy was performed and the pathological examination of the surgical specimen revealed a large papillary renal cell carcinoma (RCC). Five weeks after surgery, the patient died because of progressive cardiac failure. At autopsy, a whitish-gray subendocardial mass, measuring 6 cm in its main diameter, was discovered in the left ventricle. Histologically, the tumour, consisted of interlacing bundles of spindle cells, showing large vesicular nuclei, with prominent nucleoli. Rare gland-like structures lined by neoplastic cells were occasionally found. Neoplastic cells were focally immunoreactive to anti-cytokeratin and anti-epithelial membrane antigen antisera. The diagnosis was that of cardiac involvement by RCC with sarcomatoid features. Cardiac metastases by RCC are rare and their incidence ranges from 1.3% to 4.2%. In the present case, the sarcomatoid appearance of the cardiac lesion raises the problem of the differential diagnosis with primary cardiac sarcoma. The clinico-pathological features of this case are discussed and the literature on this topic is reviewed.