Devoted to diagnostic and interventional spine imaging and therapeutics


Primary Diffuse Leptomeningeal Gliomatosis (PDLG) 2005

General Spine

Christopher K Moses, MD
Jayne Seekins , DO, Non ASSR Member
Abbie Cluver , MD, Non ASSR Member
Zoran Rumboldt , MD, Non ASSR Member
Nada Besenski , MD, Non ASSR Member


A 19-year-old white male presented in the summer of 2003 with episodic, debilitating headaches starting after severe dehydration requiring IV rehydration. The headaches were worse in the morning and with sneezing or coughing. MR imaging showed small caliber transverse venous sinus thrombosis left worse than right and lumbar puncture demonstrated an increased opening pressure of 50 cm water. He was started on anticoagulation and was discharged. He then returned soon after for worsening headaches and was found to have papilledema bilaterally. Cranial nerves were intact. On catheter venogram no clot or stenosis was found; therefore, anticoagulation was stopped. All of the patient�s serum and CSF blood work was negative except for hypercellular, predominantly monocytic cells, with no malignant cells, suggesting aseptic meningitis. The patient had intermittent lumbar punctures for symptom relief. Repeat MRI demonstrated increased T1 signal intensity and diffuse thickening and contrast enhancement of the leptomeninges. The patient presented to a different institution for a second opinion and developed a third nerve palsy for which a VP shunt was placed.

After discharge he developed bilateral, left worse than right lower extremity paresis. The patient then went to another institution for a third opinion. Neuroaxis imaging was repeated and demonstrated abnormal leptomeningeal thickening and contrast enhancement within majority of the spinal cord (Images 1 and 2). The patient underwent a laminectomy from T12-L1 and biopsy was negative for all fungal, bacterial, viral and acid fast tests. Pathology showed pleomorphic cells with large hyperchromatic irregular nuclei that were GFAP immunostain positive, and the patient was diagnosed with a malignant neoplasm with glial differentiation consistent with leptomeningeal gliomatosis (Images 3 and 4). The patient was started on Temozolomide and radiation therapy for a total of 37.5 GyTD/15fx. The patient then developed near total bilateral lower extremity plegia. He had urinary retention, but no bowel dysfunction. He reported pain in the lower back and legs. Upper extremity function was normal. There was sensory level at T12. Two weeks later the patient presented with new onset tonic-clonic seizures. Brain MR imaging was consistent with posterior reversible encephalopathy and no change in the meningeal gliomatosis. The patient was placed on Dilantin, and there have been no further seizures. The clinical condition has progressed to decreased perianal sensation but maintains the urge to defecate. He no longer has headaches but at times has diplopia. Interval repeat MRI of the neuroaxis demonstrates decrease in overall leptomeningeal nodularity. The patient has been placed on a decadron and Temozolomide taper.

Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare fatal neoplastic syndrome characterized by widespread infiltration of the meninges by tumor apparently arising from heterotopic glial nests, but without evidence of tumor within the brain or spinal cord. Heterotopic glial nests occur in the subarachnoidal space in about 1% of unselected necropsies, most often affecting medulla (57%), and with a higher incidence (25%) in patients with congenital malformation of the nervous system (1,2,3).

Heterotopic cell nests in the leptomeninges can cause a clinical picture similar to chronic infectious meningitis (4,5). Headache, papilledema, neck stiffness, back pain, paresthesia, lower extremity paresis and incontinence are common symptoms. Negative cytology is a common finding in PDLG, while in secondary gliomatosis cytology is often an aid in diagnosing the etiology.

On imaging, diffuse, or less commonly, nodular meningeal enhancement involving brain, spinal cord and cauda equina with clumped nerve roots is common (3,4,6). Differential diagnosis of clumped nerve roots includes primary brain tumor (ependymoma, medulloblastoma), arachnoiditis, infection (TB, CMV, HIV, Brucellosis, and Rocky Mountain spotted fever), lymphoma, sarcoid and Dejerine-Sottas disease. Leptomeningeal gliomatosis may also simulate occlusive vasculopathy such as multifocal infarcts and cerebral vasculitis

This case serves as a reminder that diffuse leptomeningeal thickening of a glial nature can occur in the absence of a primary intra-axial tumor. The diagnosis of PDLG should be applied only when no other primary tumor is found. PDLG should not be confused with much more often occurring secondary meningeal gliomatosis due to primary CNS tumors, primary CNS lymphoma, or any other disease which may present with clumped nerve roots on imaging.


1. Cooper IS, Kernohan JW. Heterotopic nests in the subarachnoid space: histologic characteristics, mode of origin and relation to meningeal gliomas. J Neuropathol Exp Neurol 1951;10:16-21
2. Barborie A, Dunn EM, and Bridges LR, et al. Primary Diffuse leptomeningeal gliomatosis predominantly affecting the spinal cord: case report and review of the literature. J Neurol Neurosurg Psychiatry 2001;70:256-258
3. Kastenbauer S, Danek A, Klein W, et al. Primary diffuse leptomeningeal gliomatosis: unusual MRI with non-enhancing nodular lesions on the cerebellar surface and spinal leptomeningeal enhancement. J Neurol Neurosurg Psychiatry 2000;69:385-388
4. Ho KL, Hoshner SA, Wolfe DE. Primary leptomeningeal gliomatosis symptoms suggestive of meningitis. Arch Neurol 1981;38:662-666
5. Rees JH, Balakas N, Agathonikou A, et al. Primary diffuse leptomeningeal gliomatosis simulating tuberculous meningitis. J Neurol Neurosurg Psychiatry 2001;70:120-122
6. Pingi A, Trasimeni G, Di Biasi C, et al. Diffuse leptomeningeal gliomatosis with osteoblastic metastases and no evidence of intraaxial lesions. AJNR 1995;16:1018-1020