Sigmoid Colon Metastasis from Sarcomatoid Renal Cell Carcinoma

The sarcomatoid histological type of renal cell carcinoma is a clinically aggressive variant of parenchymal tumor, typically resistant to systemic treatment. We report the case of a 65-year-old female patient who had undergone a left radical nephrectomy for a sarcomatoid renal cell carcinoma together with enucleation of a mass of the right kidney and a contralateral nodule diagnosed as clear cell carcinoma. One year later lung, adrenal and sigmoid colon metastases from sarcomatoid renal cell carcinoma were detected and the patient was started on systemic immunotherapy with interleukin-2 and interferon-alpha. Computed tomography showed marked disease progression and the patient died 3 weeks later. Sigmoid colon metastasis from a primary sarcomatoid renal cell carcinoma has never been described in the literature.