We present a case of synchronous, bilateral renal cell carcinoma with osseo
us metaplasia. In renal cell carcinoma, bone can originate th rough two dif
ferent processes: osseous differentiation or osseous metaplasia. The case w
e report here represents the second process. We discuss pathological differ
ential diagnosis and prognosis of the infrequent tumor. Copyright (C) 2001
S. Karger AG, Basel.