DIFFUSE CRANIOSPINAL SEEDING FROM A BENIGN 4TH VENTRICLE CHOROID-PLEXUS PAPILLOMA - CASE-REPORT

Choroid plexus papillomas can metastasize to the subarachnoid space, b ut extensive metastasis has only been reported when the tumors are mal ignant. The authors report a case of diffuse, extensive metastasis to the craniospinal leptomeninges from a benign fourth ventricular choroi d plexus papilloma in an adult. This 19-year-old woman presented with a 2-year history of headache, blurred vision, diplopia, and ataxia. Ma gnetic resonance imaging of the brain and spinal cord revealed obstruc tive hydrocephalus caused by a 4-cm, partially calcified, inhomogeneou sly enhancing tumor of the fourth ventricle that was displacing the pe ns, medulla oblongata, and cerebellum. Innumerable cystic lesions of v arying size were also seen in the cranial and spinal leptomeninges. Hi stological examination of the resected fourth ventricular tumor and of a few of the leptomeningeal lesions revealed a benign choroid plexus papilloma and leptomeningeal choroid plexus cysts. This singular case of diffuse and extensive metastasis to the craniospinal leptomeninges from a histologically benign fourth ventricular papilloma adds to the available information about the biological potential of these tumors a nd expands the differential diagnosis of posterior fossa lesions with subarachnoid metastasis.