MRI manifestations of leptomeningeal metastasis.

Twenty-six cases with leptomeningeal metastasis were analyzed and Gd-DTPA enhanced MR imaging was found to be the most useful tool for making the diagnosis. The important manifestations in order of frequency were: 1) leptomeningeal enhancement; 2) ependymal enhancement; 3) plaque, nodule or mass in the subarachnoid space or ventricles; 4) nerve root thickening; and 5) ventricular dilatation not related to the obstruction of the primary neoplasm. A review of the literature has shown that intracranial leptomeningeal metastasis from spinal cord astrocytoma are very rare. In our series, 3 cases with primary brain tumors developed spinal subarachnoid involvement. This paper also reviews 1 case with thoracic cord astrocytoma which developed multiple intracranial leptomeningeal metastasis.