Tubulocystic oncocytoma of the kidney: a case study and review of literature with focus on implications for differential diagnosis.

Renal oncocytoma (RO) can rarely present with a multilocular or tubulocystic growth pattern that may cause significant diagnostic difficulties with a variety of cystic renal cell carcinomas (RCC). Distinguishing these RO variants from their many RCC mimickers is critical because of its typical benign clinical course. Herein, we report a case of RO with extensive tubulocystic architectures on a 42-year-old female patient and discuss the clinicopathologic characterizations of this unusual RO variant with an emphasis on the wide spectrum of differential diagnoses of a variety of primary or secondary renal tumors that are featuring of both oncocytic cell changes and tubulocystic growth patterns.