Primary diffuse leptomeningeal gliomatosis in children: a clinical pathologic correlation.

PURPOSE: To describe a rare case of primary diffuse leptomeningeal gliomatosis (PDLG) presenting with progressive proptosis and direct involvement of the optic nerve sheath in a child and review of the relevant literature.

METHODS: Retrospective review of a single case and systematic literature review of 26 biopsy-proven cases reported in the MEDLINE-indexed English literature. A 10-year-old girl developed proptosis and progressive visual loss associated with thickening of the optic nerve sheaths and dilation of the subarachnoid spaces with multilobulated appearance of the brain meninges and thickened peripheral nerve root sheaths. Biopsy of the optic nerve sheath was diagnostic. The patient underwent chemotherapy combined with oral temozolomide and conformational radiotherapy to the brain and spine. She died 3 years after the onset of the disease. An extensive review of the published literature using the key words "primary diffuse leptomeningeal gliomatosis" and "optic nerve" confirmed the case herein reported to be the first case of primary diffuse leptomeningeal gliomatosis in which direct optic nerve infiltration was demonstrated during the course of the disease.

RESULTS: Immunohistochemistry demonstrated expression of CD56 and glial fibrillary acidic protein, and an elevated level of Ki-67; all the other markers were negative.

CONCLUSIONS: According to a comprehensive literature review, we report the first case of PDLG that presented with bilateral proptosis and direct involvement of the optic nerve during the course of the disease. These new findings may explain an alternative mechanism of visual loss and proptosis in PDLG. We emphasize the importance of close collaboration between neurologists and ophthalmologists in all cases of visual symptoms associated with a neurologic condition. In case of optic nerve involvement, ophthalmologists could provide an easier route to achieve tissue specimen early in the course of this rare and fatal disease.