Collision tumor of meningioma and metastatic renal clear cell carcinoma: a case report.

Distinct tumors in direct contact with one another are known as collision tumors and collision tumors of meningioma and metastatic renal cell carcinoma have not been previously reported. We report a 71-year-old female with a history of renal cell carcinoma who was presented with slow response and gait imbalance for 4 months. Brain MRI showed a mass in the base of right middle cranial fossa. The mass was completely removed. Histopathologic and radiographic findings provided evidence for a collision composed of meningioma and metastatic renal clear cell carcinoma.