Leptomeningeal disease (LMD) occurs when cancer cells spread to the leptomeninges—the two inner layers of tissue that cover the brain and spinal cord (the arachnoid mater and pia mater). Instead of forming one solid tumor, LMD involves cancer cells circulating in the cerebrospinal fluid (CSF) and coating the surface of the brain and spinal cord.
Unlike primary brain tumors, LMD is usually a complication of another cancer, most often breast cancer, lung cancer, or melanoma, though it can also occur with some blood cancers and brain tumors.
Types and Classification
LMD is not classified by tumor type itself but rather by the cancer that has spread to the leptomeninges. For example:
Breast cancer–related LMD
Lung cancer–related LMD
Melanoma-related LMD
Hematologic cancers (like leukemia or lymphoma) with LMD
Doctors may also describe LMD by how it appears on imaging:
Linear enhancement → Cancer cells spread diffusely along the meninges.
Nodular enhancement → Small nodules or clumps of cancer cells are seen in the meninges or CSF.
Locations
By definition, LMD affects the leptomeninges and CSF pathways around the:
Brain
Spinal cord
Nerve roots
Because the cerebrospinal fluid circulates throughout the brain and spinal cord, LMD symptoms can occur in multiple areas of the central nervous system at once.
Population and Risk Factors
Primary cancer type: More common in people with breast cancer, non-small cell lung cancer, small cell lung cancer, or melanoma.
Advanced disease: Typically occurs in later stages of cancer, though it may rarely be the first sign of spread.
Age: Most often diagnosed in adults, but can occur in children with leukemia or brain tumors.
Other factors: Cancers with a tendency to spread to the brain have a higher risk of causing LMD.
Symptoms
Because LMD can affect the brain, spinal cord, and nerves all at once, symptoms are often widespread and varied:
Brain-related symptoms:
Headaches
Nausea/vomiting
Cognitive changes or confusion
Seizures
Spinal cord symptoms:
Back pain
Weakness or numbness in arms or legs
Problems with walking or balance
Nerve involvement:
Double vision or vision loss
Hearing changes
Difficulty swallowing or speaking
Symptoms often develop gradually but can become severe quickly, making early recognition critical.
Treatment
While there is no single cure for LMD, treatments aim to slow progression, control symptoms, and improve quality of life:
Intrathecal chemotherapy: Chemotherapy delivered directly into the CSF through a lumbar puncture or an Ommaya reservoir.
Systemic therapy: Certain targeted therapies or immunotherapies may cross into the CSF and help treat LMD.
Radiation therapy: Can be used to relieve symptoms in specific areas of the brain or spine.
Supportive care: Steroids, anti-seizure medications, and pain management are often part of care.
Clinical trials: New drugs and approaches are being studied to improve outcomes for LMD patients.
Questions to Ask Your Doctor
How did my cancer spread to the leptomeninges?
What are the treatment options available for my specific type of cancer with LMD?
Is intrathecal chemotherapy or targeted therapy an option for me?
What symptoms should I expect, and how can they be managed?
Are there clinical trials I may be eligible for?
What is the goal of treatment—control, symptom relief, or both?
What resources are available for me and my family to cope with this diagnosis?