Sarcomatoid renal cell carcinoma.

Sarcomatoid renal cell carcinoma (SRCC) is an aggressive tumor variant thought to arise predominantly from differentiation of clear cell carcinoma. A few reports of SRCC associated with non-clear cell tumors led to the presumption that SRCC may arise from any renal cell carcinoma, although direct evidence of this is lacking. We report a case of a 70-year-old male patient, who presented with acute left upper quadrant abdominal pain and was diagnosed to have SRCC after pathological examination. The patient is on high dose interleukin (IL-2)-based immunotherapy and is apparently free of disease six months after surgery.