Intermediate
Technical
IVT
leptomeningeal dissemination
Spread of tumor cells throughout the subarachnoid space via cerebrospinal fluid circulation.
Full Definition
Leptomeningeal dissemination refers to the spread of malignant cells throughout the subarachnoid space and cerebrospinal fluid pathways, involving the pia mater and arachnoid membranes. This process occurs when tumor cells gain access to CSF and circulate throughout the neuraxis, potentially forming secondary deposits along nerve roots, ventricular surfaces, and cortical sulci. It is particularly common with certain brain tumors such as medulloepitheliomas, ependymomas, and choroid plexus carcinomas, and significantly worsens prognosis.
Usage
Usage note: Distinguish from pachymeningeal (dural) involvement; specify imaging or CSF findings when present.
In Context
- "MRI revealed extensive leptomeningeal dissemination with nodular enhancement along the spinal cord surface." — Neuroimaging report
- "CSF cytology confirmed leptomeningeal dissemination of the primary ependymoma." — Cerebrospinal fluid analysis
Also known as
CSF dissemination
meningeal carcinomatosis
leptomeningeal metastasis
Contrasted with
localized tumor
Don't confuse with
dural metastasis
pachymeningeal involvement