Polar spongioblastoma with cerebrospinal fluid metastases.

We presented a rare case of polar spongioblastoma occurring in a 12-year-old boy with cerebrospinal fluid (CSF) spread in the basal cisterns and contralateral ventricle, as well as metastases to the spinal dura. Apart from the typical palisades of elongated cells, immunohistochemically, the tumor cells stained for neuron-specific enolase and synaptophysin, and ultrastructural examination revealed features of neuronal differentiation. Our case adds to the small number of cases of polar spongioblastoma with clinicopathologic features and ultrastructural appearance described and confirms the neuronal nature of the tumor. It also represents the second documented case with CSF metastases.