Extremely delayed falx metastasis from renal cell carcinoma.

A65-year-old man was admitted because of the progressive onset of left faciobrachiocrural paresis. Twenty years previously, he underwent a right nephrectomy for renal cell carcinoma; initial diagnosis was made by CT scan, because of the onset of hematuria; after nephrectomy, no adjuvant therapy was made. Brain MRI showed an extra-axial lesion of the falx, suspicious for meningioma (figure 1). Total removal of tumor and infiltrated falx was performed. Histopathology revealed meningeal metastasis of renal cell carcinoma (figure 2). A total body CT scan and a bone scintigraphy excluded any other neoplastic lesions. We describe the first case of falx metastasis from renal cell carcinoma; the patient is in good condition after radiochemotherapy at 4-month follow-up. Dural metastases after renal cell carcinoma are very rare.1 Latency of more than 10 years after nephrectomy is unusual.2 In our case, MRI findings, such as homogeneous contrast enhancement and dural tail sign, were suggestive for meningioma. Perilesional edema can be observed in association with specific subtypes of meningioma, although it could raise the suspicion of a more malignant lesion. It has been observed that the main differential diagnosis of dural metastasis is meningioma because of the absence of definite radiologic criteria.1