Renal cell carcinoma occurring with contralateral adrenal metastasis: a clinical and pathological trap.

Because renal cell carcinoma occasionally occurs in manifestations referable to a single metastatic lesion, there is a risk that a metastasis will be mistaken for the primary tumor. Histologic examination can compound the confusion, particularly when a clear cell carcinoma of the kidney metastasizes to an organ, such as lung, liver, adrenal, or skin, where clear cell tumors may occur as primary lesions. Although advanced renal cell carcinoma not infrequently involves the adrenal gland, the clinical and pathologic setting establishes the tumor in the adrenal as a metastasis. Two patients are described to illustrate what is to our knowledge the heretofore undescribed occurrence of renal cell carcinoma as a metastasis to the contralateral adrenal gland.