Differential Diagnosis for Leptomeningeal Enhancement
- Single Most Likely Diagnosis
- Meningitis (infectious or inflammatory): This is the most common cause of leptomeningeal enhancement, which can be due to bacterial, viral, or fungal infections, as well as inflammatory conditions such as sarcoidosis or rheumatoid arthritis. The enhancement pattern is typically diffuse and symmetrical.
- Other Likely Diagnoses
- Leptomeningeal metastases: Cancer cells can spread to the leptomeninges, causing enhancement on imaging. This is more common in patients with a history of cancer, particularly breast, lung, or melanoma.
- Neurosarcoidosis: This condition can cause leptomeningeal enhancement due to granulomatous inflammation.
- Multiple sclerosis: Although more commonly associated with white matter lesions, multiple sclerosis can also cause leptomeningeal enhancement, particularly in the context of active disease.
- Do Not Miss Diagnoses
- Subarachnoid hemorrhage: Although often diagnosed clinically and with non-contrast CT, subarachnoid hemorrhage can cause leptomeningeal enhancement on contrast-enhanced imaging, particularly in the subacute phase.
- CNS vasculitis: Conditions like giant cell arteritis or primary CNS vasculitis can cause leptomeningeal enhancement and require prompt diagnosis to prevent further complications.
- Lyme disease (neuroborreliosis): In endemic areas, Lyme disease can cause leptomeningeal enhancement, particularly in the context of meningitis or radiculitis.
- Rare Diagnoses
- Chronic lymphocytic inflammation with pontine atrophy (CLIP): A rare condition characterized by leptomeningeal enhancement and pontine atrophy.
- Histiocytosis: Conditions like Langerhans cell histiocytosis or Erdheim-Chester disease can cause leptomeningeal enhancement, although this is relatively rare.
- Whipple disease: A rare systemic bacterial infection that can cause leptomeningeal enhancement, among other neurological symptoms.