Table 1.
Summary of the key imaging features of a collection of cases with leptomeningeal masses and their mimics.
| Category | Condition | Imaging Characteristics |
|---|---|---|
| Malignant Tumors | Leptomeningeal Carcinomatosis | Nodular, thick, or linear enhancement of pia, ependyma, sulci, folia, cranial nerves |
| CNS Lymphoma | Leptomeningeal enhancement with parenchymal mass on contrast-enhanced MRI | |
| Pineal Region Tumors | Leptomeningeal metastases with drop metastases along the spinal canal, enhancement | |
| Benign Tumours | Schwannoma | Nodular enhancement of nerve roots, can mimic leptomeningeal enhancement |
| Myelomatosis | Diffuse leptomeningeal and pachymeningeal enhancement with bony involvement | |
| Tumour Mimics | Intracranial Hypotension | Diffuse pachymeningeal enhancement, slit ventricles on MRI |
| Epidural Lipomatosis | Fat accumulation in epidural space, high signal intensity surrounding cauda equina | |
| Subarachnoid Hemorrhage | FLAIR hyperintensity in cerebral sulci, corresponding susceptibility on MRI | |
| Syringomyelia | Congestion of epidural venous plexus | |
| Sturge-Weber Syndrome | Cortical atrophy, gyriform calcification with serpentine leptomeningeal enhancement | |
| Meningoencephalitis | Linear or nodular leptomemingeal enhancement | |
| Cerebral ischaemia / infarction | Congested leptomeningeal vessels |