Spinal leptomeningeal neoplastic disease. Evaluation by MR, myelography and CT myelography.

Out of 16 patients, spinal leptomeningeal neoplastic disease was diagnosed by MRI in 4 patients, myelography in 14 patients and CT myelography in 12 cases. MR was superior to myelography in 2 patients, in another 2 patients MRI was equally diagnostic. The cerebrospinal fluid of every patient contained malignant cells. Histological evidence for primary central nervous system tumors was found in 5 cases. In 10 cases, non-neuraxial malignancy consisted of small cell carcinoma of the lung (7 cases), and leukemia and lymphoma (3 patients). In 1 patient, primary leptomeningeal malignant melanoma was confirmed at autopsy. Preferential thoracolumbar neoplastic morphologic manifestation correlated with the presence of conus and cauda equina syndrome in 9 patients, low back pain, paresthesia and spinal root signs in 7 patients. False-negative interpretation of myelography in 2 patients with positive MR findings, and the impressive sensitivity of gadolinium Dota to improve visualization of subarachnoid spread, favor MRI as an alternative imaging technique in the assessment of patients with suspected intradural extramedullary malignancy.