Adrenocortical carcinoma can have a clinical presentation that mimics a primary renal tumor. We describe a case of a 47-year-old male who presented with flank pain, weight loss, and a 14 cm mass arising from the upper pole of the right kidney on imaging. Upon surgical resection he was found to have a 1500 gram stage II adrenocortical carcinoma. The clinical features, pathologic findings, grading criteria, and differential diagnosis of adrenocortical carcinoma are reviewed.