From the Guidelines
Leptomeningeal enhancement is primarily caused by neoplastic infiltration, infection, or inflammation affecting the leptomeninges, with common causes including bacterial meningitis, viral meningitis, fungal infections, and leptomeningeal carcinomatosis, as well as autoimmune conditions like sarcoidosis and vasculitis 1.
Causes of Leptomeningeal Enhancement
The causes of leptomeningeal enhancement can be broadly categorized into:
- Infection: bacterial meningitis, viral meningitis, fungal infections, and tuberculosis meningitis
- Malignancy: leptomeningeal carcinomatosis, which is the spread of cancer to the meninges, with the most common solid tumors associated with meningeal dissemination being breast cancer, lung tumors, melanoma, and cancer of the gastrointestinal system 1
- Autoimmune conditions: sarcoidosis, vasculitis, and multiple sclerosis
- Other causes: subarachnoid hemorrhage, recent surgery, and certain medications or contrast agents
Diagnosis and Treatment
The enhancement occurs due to increased blood-brain barrier permeability, allowing contrast material to leak into the subarachnoid space during imaging studies, appearing as abnormal brightness or enhancement of the meninges on contrast-enhanced MRI or CT scans 1. Proper diagnosis requires correlation with clinical symptoms, laboratory findings from cerebrospinal fluid analysis, and sometimes meningeal biopsy to determine the specific underlying cause and guide appropriate treatment. Treatment is often palliative, involving radiotherapy and chemotherapy, with the goal of stabilizing neurologic status and prolonging survival 1.
From the Research
Causes of Leptomeningeal Enhancement
The causes of leptomeningeal enhancement can be diverse, including both neoplastic and non-neoplastic conditions. Some of the possible causes include:
- Malignant conditions such as leptomeningeal carcinomatosis, myelomatosis, schwannoma, CNS lymphoma, and pineal region tumors 2
- Inflammatory conditions such as neurosarcoidosis 3, meningoencephalitis 2, and IgG4-related hypertrophic meningitis 4
- Infectious conditions such as tuberculous meningitis 5
- Other conditions such as intracranial hypotension, cerebral ischemia/infarction, epidural lipomatosis, syringomyelia, Sturge-Weber syndrome, and subarachnoid hemorrhage 2
- Rare conditions such as diffuse leptomeningeal glioneuronal tumor (DLGNT) 5
Neoplastic Causes
Neoplastic conditions can cause leptomeningeal enhancement, including:
- Leptomeningeal carcinomatosis, which is a rare cancer complication occurring in ~5% of cases 6
- Myelomatosis, which is a type of blood cancer that can affect the central nervous system 2
- Schwannoma, which is a type of tumor that arises from the nerve sheath 2
- CNS lymphoma, which is a type of cancer that affects the central nervous system 2
- Pineal region tumors, which are rare tumors that occur in the pineal gland 2
Non-Neoplastic Causes
Non-neoplastic conditions can also cause leptomeningeal enhancement, including:
- Neurosarcoidosis, which is an inflammatory condition that can affect the central nervous system 3
- Meningoencephalitis, which is an inflammation of the brain and meninges 2
- IgG4-related hypertrophic meningitis, which is a rare inflammatory condition that affects the meninges 4
- Intracranial hypotension, which is a condition characterized by low pressure in the brain 2
- Cerebral ischemia/infarction, which is a condition characterized by lack of blood flow to the brain 2