Primary leptomeningeal anaplastic oligodendroglioma with a 1p36-19q13 deletion: report of a unique case successfully treated with Temozolomide.

Primary leptomeningeal oligodendroglioma occurs very rarely and in only one patient a deletion of chromosome 1p has been reported. We describe a 60-year-old man with a prior history of an epileptic seizure three years earlier, who was referred because of depression and a rapid evolving cognitive impairment. Brain MRI showed a diffuse right parieto-occipital subarachnoid enhancing lesion without intra-axial extension. The diagnosis of an anaplastic oligodendroglioma (WHO grade 3) was made on pathological examination. Molecular analysis using the FISH technique revealed a combined deletion of chromosomes 1p36 and 19q13. A rapid progression of the lesion was shown on MRI with leptomeningeal spinal metastases. The patient was treated with Temozolomide (TMZ) 150 mg/m(2) for 5 days every 4 weeks and showed a marked clinical recovery. Serial MRI disclosed a near complete regression of the lesions with no residual enhancement left after 6 cycles of chemotherapy. At progression following 8 cycles of TMZ the patient underwent craniospinal radiotherapy with complete response of his disease. To our knowledge this is the first report of a patient with a primary leptomeningeal anaplastic oligodendroglioma with diffuse spinal seeding bearing a 1p36/19q13 deletion. Our patient achieved a durable clinical and radiological remission following TMZ treatment. Molecular analysis with determination of chromosome 1p/19q deletions should be performed in all cases of leptomeningeal gliomas to select those patients who might benefit from TMZ chemotherapy.