Metastatic Renal Cell Carcinoma With Sarcomatoid Features.

A previously healthy woman, aged 38 years, presented with a 3-month history of fatigue, dyspnea on exertion, significant weight loss, and severe left flank pain; her symptoms restricted any work activities. Laboratory test results were notable for hypercalcemia (corrected serum calcium, 12.8 mg/dL), anemia (9.