Acute acalculous cholecystitis in patients with clear cell renal cell carcinoma treated with sunitinib: report of two cases.

Although sunitinib is associated with a variety of adverse events, cases of sunitinib-related acute cholecystitis have rarely been reported. We herein report two cases of sunitinib-related acute acalculous cholecystitis in patients with clear cell renal cell carcinoma. In both cases, the gallbladder was surgically removed because it was difficult to improve the patient's condition with the cessation of sunitinib and non-surgical treatment only. Attention must be paid to the possibility of sunitinib-related acute cholecystitis, which, although uncommon, can be life-threatening.