Brain metastasis in renal cell carcinoma: clinical data and neuropathological differential diagnoses.

Beside lung and skeleton, renal cell carcinoma (RCC) can also metastasize to the brain. In order to collect clinical and histopathological data on these tumors, we studied the local distribution of 50 metastases of RCC in different brain regions (frontal, parietal, temporal occipital lobe and brain stem/cerebellum) and found frequencies ranging from 18.4% to 22.4% in each region. This indicates that there is no preferable site of renal cell carcinoma metastases in the brain. In 46 (92%) of the cases the primary tumor or metastases in other organs had already been diagnosed before operation of a brain metastasis. This shows that the latter mostly is a late manifestation at an advanced stage of disease. 44 (88%) of the metastases showed the typical clear cell pattern. In case of unknown primary tumor, these have to be distinguished from other potentially intracranial neoplasms with similar histologic features. These are chordoma, germinoma, paraganglioma, alveolar sarcoma of soft tissue and the epitheloid variant of malignant peripheral nerve sheath tumor.