Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare cause of leptomeningeal enhancement. Here, we describe the clinical features, neuroimaging findings, and course of a unique case of spinal predominant PDLG.

A 52-year-old woman presented to the emergency department with 12 weeks of progressive lower extremity paresthesias. MRI of the spine demonstrated longitudinally extensive T2 hyperintensity throughout the cervical, thoracic, and lumbar spinal cord with diffuse leptomeningeal and subpial enhancement. A lumbar puncture showed a lymphocytic pleocytosis of 22 total nucleated cells and elevated protein of 280 mg/dL. Other infectious and inflammatory studies, as well as cytology and flow cytometry, were unremarkable. FDG-PET of the body demonstrated hypermetabolic activity throughout the spine. Biopsy of the spine was performed and confirmed a diagnosis of PDLG.

PDLG is a rare cause of diffuse spinal cord leptomeningeal enhancement. The initial differential is broad, including infectious (e.g., tuberculous meningitis), inflammatory (e.g., sarcoidosis), and neoplastic considerations. Symptoms and signs at presentation are non-specific but can indicate increased intracranial pressure, cranial nerve palsies, seizures, and/or spinal cord pathology, as in our case. Diagnostic evaluation includes imaging of the neuroaxis and lumbar puncture, with nonspecific CSF profiles typically revealing pleocytosis, elevated protein, and occasionally hypoglycorrhachia. MRI will classically demonstrate diffuse leptomeningeal enhancement. tissue biopsy is required to make the diagnosis. PDLG often has a genetic profile identical to primary glioblastomas and the reasons for immediate involvement of the CSF are not understood.  PDLG is associated with a poor prognosis and there is no standardized treatment at this time.