leptomeninges
Pronunciation: lep-toh-meh-NIN-jeez
The two innermost layers of the meninges (pia mater and arachnoid mater), commonly involved in inflammatory and neoplastic processes.
Full Definition
The collective term for the pia mater and arachnoid mater, which together form the inner two layers of the meningeal covering of the brain and spinal cord. The leptomeninges are separated from the outer dura mater by the subdural space and contain the subarachnoid space through which cerebrospinal fluid circulates. These delicate membranes are frequently involved in pathological processes including meningitis, carcinomatosis, and hemorrhage. In neuropathological examination, leptomeningeal pathology often presents as thickening, inflammation, or tumor infiltration that can significantly impact cerebrospinal fluid dynamics and neurological function. Editorial attention should focus on proper anatomical terminology and accurate description of leptomeningeal versus pachymeningeal involvement.
Usage
Usage note: Always plural; distinguish from pachymeninges (dura mater) in pathological descriptions.
In Context
- "Chronic leptomeningeal inflammation was characterized by lymphocytic infiltration and fibrosis." — Autopsy report
- "Leptomeningeal carcinomatosis showed extensive involvement of the basal cisterns and sylvian fissures." — Diagnostic report