Sarcomatoid renal cell carcinoma: a case report and literature review.

Renal cell carcinoma (RCC) is the most common malignancy of the kidney and consists of multiple subtypes. The sarcomatoid variety, while previously considered a distinct histologic subtype, is now categorized as a form of dedifferentiated carcinoma. When present, it is associated with a significant decrease in patient survival due to its rapid growth and intrusive behavior. Preoperative knowledge of this diagnosis may be beneficial to clinicians in order to modify treatment options and follow-up protocols. This report describes a case of sarcomatoid renal cell carcinoma in which the patient initially presented with flank pain. We then discuss the clinical features of sarcomatoid renal cell carcinoma and its imaging appearance on computed tomography (CT), and succinctly review the subtypes of renal cell carcinoma and their imaging characteristics.